Neuroscience and Biobehavioral Reviews 128 (2021) 199–217

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Neuroscience and Biobehavioral Reviews

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From many to (n)one: Meditation and the plasticity of the predictive mind
Ruben E. Laukkonen a, b, *, Heleen A. Slagter a, b, *
a
Vrije Universiteit Amsterdam, Netherlands
b
University of Amsterdam, Netherlands

A R T I C L E I N F O A B S T R A C T

Keywords: How profoundly can humans change their own minds? In this paper we offer a unifying account of decon­
Meditation structive meditation under the predictive processing view. We start from simple axioms. First, the brain makes
Predictive processing predictions based on past experience, both phylogenetic and ontogenetic. Second, deconstructive meditation
Plasticity
brings one closer to the here and now by disengaging anticipatory processes. We propose that practicing
Sense of self
Brain
meditation therefore gradually reduces counterfactual temporally deep cognition, until all conceptual processing
Attention falls away, unveiling a state of pure awareness. Our account also places three main styles of meditation (focused
Predictive brain attention, open monitoring, and non-dual) on a single continuum, where each technique relinquishes increas­
Insight ingly engrained habits of prediction, including the predicted self. This deconstruction can also permit certain
Consciousness insights by making the above processes available to introspection. Our framework is consistent with the state of
Non-dual awareness empirical and (neuro)phenomenological evidence and illuminates the top-down plasticity of the predictive mind.
Experimental rigor, neurophenomenology, and no-report paradigms are needed to further understanding of how
meditation affects predictive processing and the self.

1. Introduction entropy and the dissolution of its boundaries, Karl Friston’s Free Energy
Principle (2010) and predictive processing more broadly, is gaining
Thousands of meditation practitioners going back at least three scientific traction as an all-encompassing account of living organisms. It
millennia have reported accessing states far outside the ordinary mind. recharacterizes organisms as fundamentally anticipatory—as continu­
Meditators, even in laboratory settings, report that aspects of experience ously inferring or predicting the outside world based on prior experi­
that we often take to be stable and unchanging, such as time, space, and ence. This framework supposes to explain everything from the behavior
self, can be modulated in profound ways (Ataria et al., 2015; Berko­ and computations of unicellular organisms to the complex cognitive and
vich-Ohana et al., 2013; Dor-Ziderman et al., 2013, 2016; Fingelkurts emotional inner landscapes of homo sapiens, including the self (Apps
et al., 2020; Travis and Pearson, 2000; Wahbeh et al., 2018). Moreover, and Tsakiris, 2014), through one and the same mechanism: free energy
according to many of these meditation traditions attaining such changes minimization (Bruineberg et al., 2018). Due to the fact that the brain
in experience are desirable and permit one to lead a happier and more lacks direct access to the external world, it must ‘guess’ or predict the
compassionate life. Mindfulness meditation-based interventions are also hidden causes of sensory input based on past experience in order to
now a conventional treatment for mental disorders in some countries adaptively interact with it. To improve its predictions, the brain is
(Rycroft-Malone et al., 2017) and downloads of mindfulness apps are proposed to minimize the difference between its top-down predictions and
well into the tens of millions. The scientific study of meditation is also the sensory input (i.e., free energy or prediction error). Prediction error
growing exponentially (Van Dam et al., 2018). But as yet, there does not minimization is proposed to operate at all levels of the neural hierarchy,
exist a unifying account of how meditation generates its manifold including those detached from the present environment in service of
empirical and phenomenological effects. The lack of a general theory of future adaptive behavior. Thus, in this framework, perception, action
meditation may be partly owing to a lack of a unifying scientific account and everything in between, are constructed through predictive models
of the mind, brain, and behavior, which has been missing until relatively that have previously come to reliably reduce errors in prediction.
recently. Therefore, past experience is a pervasive factor underlying all mental
Beginning with the simple axiom that an organism must resist activity (Bruineberg et al., 2018; Limanowski and Blankenburg, 2013).

* Corresponding authors.
E-mail addresses: r.e.laukkonen@vu.nl (R.E. Laukkonen), h.a.slagter@vu.nl (H.A. Slagter).

https://doi.org/10.1016/j.neubiorev.2021.06.021
Received 23 April 2021; Received in revised form 7 June 2021; Accepted 9 June 2021
Available online 14 June 2021
0149-7634/© 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
R.E. Laukkonen and H.A. Slagter Neuroscience and Biobehavioral Reviews 128 (2021) 199–217

Obviously, having a mind that is constructed through past experi­ awareness rests in the here and now, all conceptualization including the
ences is advantageous in many situations, as it is organized to align the sense of agency should also dissipate, which ultimately is said to reveal a
individual’s needs with the possibilities in its environment. Yet, a mind “pure awareness” that contains no phenomenological model of either
that is too restricted—that too often occupies habitual modes of thinking self or world (Metzinger, 2020). And finally, the broad-scale emphasis
and feeling—and is not flexibly adapted to changing situations, can be on ‘stillness’ in body and mind may set the scene for pruning of coun­
maladaptive. Crucially, within the free energy framework, the brain terfactual models that elicit insights through what is known as ‘fact free
does not simply undergo influences from the outside, but continuously learning’ (Friston et al., 2017).
generates its own model of the environment from within based on past This paper is organized in the following way: we will begin with an
experience, a reality that is continuously tested against the outside outline of predictive processing and its key components, including views
world. This also turns the typical notion of brain plasticity—the capacity on the nature of self, insight, and fact free learning (Friston, 2018;
to undergo change (Buonomano and Merzenich, 1998; Feldman, Friston et al., 2017). We then describe the three meditation styles:
2009)—on its head (Boonstra and Slagter, 2019). That is, plasticity is not focused attention, open monitoring, and non-dual meditation (Josi­
simply the result of outside influences (or the capacity to receive form), povic, 2010; Lutz et al., 2008, 2015). We next put forward the novel
but very much about the capacity to produce form from within (Boonstra neurobiologically informed proposal that there is a single mechanism
and Slagter, 2019). This raises important questions about the plasticity which puts each of these practices clearly on a continuum. That is, each
of the predictive mind. If our inner mental landscape is determined by practice gradually reduces temporally deep processing in the brain. We will
models that through past experience have come to reliably minimize then reformulate the different meditation techniques, and associated
uncertainty, to what extent are these models still plastic or capable of changes in phenomenology, and key neural and cognitive effects of
revision based on new experiences? In other words, are there ways of meditation in terms of our model. This will cast some seminal findings in
deconstructing and reconstructing the generative models that under­ a new light, as we also discuss. Finally, we will make several testable
write our predictive mind? And, if so, can we understand the ensuing predictions that derive from our novel account and outline important
deconstruction in terms of predictive processing? avenues for future research. For example, we make state-specific and
In this paper, we argue that this new understanding of the brain as a technique-specific predictions about how meditation may affect
predictive organ coincides well with meditation, which, in some cases, habitual responding, learning, and the sense of self.
explicitly and in other cases implicitly aims at deconstructing the mind For our theory, we have chosen the name many-to-(n)one to depict
from within, in order to allow one to experience things anew, no longer the reduction in counterfactual or temporal depth1 (Corcoran et al.,
wholly determined by acquired mental habits. Therefore, here we aim 2019)—the tendency to abstract away from the present moment (Gilead
to, 1) provide a unifying account of empirical and phenomenological et al., 2019)—that occurs during meditation. There is widespread
effects of intensive deconstructive meditation practice that is grounded agreement that information is represented hierarchically in the brain,
in predictive processing, and 2) to demonstrate how scientific research with early levels of the hierarchy being more temporally precise and
on meditation can reveal novel insights into the plasticity of the pre­ concrete, and higher levels being more temporally thick and abstract
dictive mind. (Fingelkurts et al., 2010;Friston, 2008; Huntenburg et al., 2018). The
Here we use Buddhist meditation techniques as a paradigmatic quintessence of many meditation styles is also being in the present
framework. Moreover, given the rich variety of Buddhist meditation moment to the degree possible at any given time. Thus, as a heuristic
traditions and practices, for the sake of scope, we focus on three styles of version of our model, we suggest that meditation reins in the mind’s
meditation that are widely practiced within the major Buddhist tradi­ habitual tendency to abstract (many) away from the here and now until
tions (Zen, Theravada, Tibetan Buddhism), and that so far have received all phenomenological distinctions stop ((n)one).2 Metaphorically, we
the most scientific attention: focused attention (FA), open monitoring suggest that meditation prunes3 the counterfactual tree (see Fig. 1).
(OM), and non-dual (ND) meditation (Josipovic, 2010; Lutz et al., 2008,
2015). We also focus on these meditation techniques because our ac­ 2. Predictive processing
count makes the novel neurobiologically informed (Cahn and Polich,
2006) proposal that there is a single mechanism which puts each of these What does the brain do? What is the basic imperative of a living
practices clearly on a continuum. In this sense our model is about the organism? Evolution and gene selection theory were able to provide
practices and associated states and not about the ultimate goals of answers to core questions at the level of biology, explaining how life can
meditation, which can greatly vary across traditions. Our account also emerge and adapt over time through natural selection (Ashburner et al.,
aims to capture the general structure underlying these meditation styles, 2000). However, a unifying account of life within the living has yet to take
and therefore necessarily cannot account for all the nuance of every hold. Organisms in their relatively short life spans also change, adapt,
individual FA, OM and ND meditation techniques. behave, think, and feel and seem to possess some inner imperative to
The essence of our theory is quite simple. Our main contention is that survive beyond procreation. What is at the heart of this compulsion?
FA, OM and ND meditation gradually bring the practitioner more and According to the free energy principle (Friston, 2010), the basic
more into the present moment, thereby progressively abating hierar­ imperative is not pleasure seeking, or any kind of simple reinforcement
chically (i.e., temporally) deep predictive processing in the brain. We scheme. The imperative is to maintain a boundary between oneself and
contend that this not only reduces temporally extended processes, such the world, or in other words, to resist the second law of thermodynamics
as episodic future thinking and decision making, but can also explain (i.e., the tendency for isolated systems, including the human organism,
more unusual kinds of experiences reported by meditators, including to become more entropic over time). If an organism loses its boundaries,
loss of self-other distinction and the cessation of time as in non-dual it becomes more entropic as its constitution and the world become
awareness (Josipovic, 2010; Lindahl and Britton, 2019). That is, if
awareness rests in the here and now, all mental processes that involve
abstract and temporally deep processing should logically fall away, 1
including sense of self, time, space, and body representation (Fingelkurts Throughout this paper we use temporal depth, counterfactual depth, and
abstraction, rather interchangeably. They are each different characteristics of
et al., 2020). Even seemingly direct experiences, like that of a teacup,
hierarchically deep processing, and are often used interchangeably in the
demand a complex process of construction from past experience and
literature.
include anticipation of possible changes in sensory input (e.g., propri­ 2
Here ‘one’ should be understood as ‘not-two’, or non-dual (i.e., one without
oceptive and sensory changes related to drinking from the cup). More­ the concept of one).
over, experience is inherently enactive, to experience something is to 3
As the horticulturist shears away overgrown branches, meditation trims
respond to its affordances, as an agent of that response. Thus, if away the habitual conceptualization of experiences.

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Fig. 1. Here we use the Pythagoras Tree to provide an intuitive

illustration of how organisms represent the world with
increasing counterfactual depth or abstraction.24 The tree is
√̅̅̅
constructed using squares that are scaled down by 2/2 and
placed such that the corners of the squares meet and form a
triangle between them, recursively. Analogously, the brain
constructs experience from temporally precise and unimodal
models of present-moment sensory representations and input
(e.g., pixels on a screen), into ever more abstract, transmodal,
and temporally deep models (e.g., a theory paper). Meditation
brings one increasingly into the present moment, thus reducing
the tendency to conceptualize away from the here and now,
akin to observing the pixels rather than the words. This
reduction of conceptualization ought to also have profound
effects on the sense of self, which also relies on abstract model
building, and ultimately is said to reveal an underlying seem­
ingly “unconditioned” state of consciousness as such (like the
white background underlying the pixels).

increasingly inseparable. In order to avoid the dissolution of its expectations of one’s bodily volume of water via osmolality. It is not
boundaries, what the organism does is make predictions across many difficult to see then that an organism that does not aim to minimize
timescales to produce autopoietic4 actions that minimize the tendency prediction errors over time would not survive for long.
towards entropy (Friston and Buzsáki, 2016). This ensures that the or­ In order to keep our discussion focused, below we review five core
ganism continuously revisits the limited set of states conducive for its features of predictive processing that are relevant in the context of
survival. It is perhaps these relatively uncontroversial axioms on which meditation: hierarchical predictions, active inference, precision-
the free energy principle is founded that has made it so appealing to weighting, self-consciousness, and fact free learning.
philosophers and scientists alike (Allen and Friston, 2018; Clark, 2013;
Milliere and Metzinger, 2020; Wacongne et al., 2011).
The organism’s survival depends on high fidelity predictions. But 2.1. A hierarchy of expectations
how can the organism and its brain, which has no direct access to the
outside world—only to the often ambiguous and noisy sensory signals it It is a key tenet of the free energy principle that the brain models the
receives via the senses—improve its predictions? In vision, for example, world hierarchically (Friston and Stephan, 2007). Early basal levels of
the size of the image on the retina is influenced by the size of the object processing are temporally precise and concrete (e.g., sensory and
and how far it is from the observer (Proffitt, 2006). How then does the interoceptive input) and deeper levels are temporally thick and abstract
brain know merely based on the sensory activation how large or far (e.g., thoughts and concepts, Limanowski and Friston, 2020). Each level
away an object is? The computationally efficient solution to this prob­ of the hierarchy aims to predict the input of the level below, and in­
lem is for the brain to prune its models using prediction errors. By pro­ consistencies between predictions and the input (i.e., prediction errors)
cessing the difference between model predictions and sensory input the are propagated further up the hierarchy. The hierarchical nature of the
organism can indirectly quantify the accuracy of its predictions to brain is not controversial (Badcock et al., 2019; Friston, 2008; Hun­
improve the models that generated them (Friston, 2010). Focusing on tenburg et al., 2018; Kumar et al., 2007; Lee and Mumford, 2003; Taylor
minimizing prediction errors (entropy in the long-term) is computation­ et al., 2015; Vidaurre et al., 2017). We will unpack the nature of this
ally much less expensive than processing a complex temporally layered hierarchy and how it relates to self-processing and meditation in later
gamut of interoceptive and exteroceptive input in every instance. sections.
To illustrate how predictive processing works, consider the following Predictive processing accounts such as Friston’s free-energy princi­
example of drinking water. Picking up a glass of water, while avoiding ple have roots in Bayesian Brain theories (Friston and Stephan, 2007).
tipping over the dishwashing detergent, and drinking the water, entails That is, in order to answer the difficult question of, “how should I update
successful modelling of one’s body, movements, immediate visuo- my beliefs given new evidence” the brain is proposed to follow hierar­
spatial environment, as well as the internal mechanisms that prevent chical Bayesian inference. This means that the brain computes the ‘new
the water from entering the trachea. Moreover, if one is subsequently hypothesis’ (posterior probability) by considering the ‘old hypothesis’
“surprised” by the sensory input (e.g., what is meant to be water), then it (prior probability) and the likelihood of the new evidence given the ‘old
is likely that one is drinking something dangerous. Indeed, the very hypothesis’ or prior. Clearly, in this scheme, priors—intuitively analo­
desire to drink fluids is itself a prediction error arising from appropriate gous to beliefs—play a key role in what the organism ends up experi­
encing and believing, at every level of the hierarchy. These priors are
conditioned by past experience, and not just developmentally but also
phylogenetically (Badcock et al., 2019). Thus, some priors may be
4
Autopoietic actions are those that allow an organism to reproduce, regen­ deeply resistant to change (i.e., stubborn). Examples of stubborn pre­
erate, and therefore maintain itself (Maturana and Varela, 1991). dictions are expectations that critical physiological variables are within

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some range (e.g., a bodily temperature of ~37 degrees Celsius), and the may spend considerable time and energy in ruminating about such
expectation that one has a body (Yon et al., 2019). Predictions estab­ possibilities (Nolen-Hoeksema et al., 2008; Rimes and Watkins, 2005).
lished ontogenetically are conceivably less stubborn than predictions
that are necessary for survival and developed phylogenetically, but an 2.3. Attention
important outstanding question is to what extent these predictions once
established, e.g., after sensitive periods in development, can still be Simply revising beliefs whenever prediction errors occur is ulti­
modified based on new experiences and learning (Yon et al., 2019). mately not beneficial, as incoming signals are often unreliable or noisy
or not representative of the larger world. Hence, the reliability or pre­
cision of prediction errors ought to also play a role. That is, not only the
2.2. Perceptual and active inference
upcoming sensory input needs to be estimated, but also its precision
(second-order prediction), which requires integrating information over
Prediction errors can be minimized in two ways: an organism can
time (Friston, 2009). In predictive processing, attention is equated with
change its models, or it can act in ways that are consistent with expecta­
precision-weighting and plays a key role in contextualising prediction
tions. Put differently, one can revise (perceptual inference) or confirm
errors (Feldman and Friston, 2010). Intuitively, attention partly de­
(active inference): like a scientist who either changes their theory in
termines whether one changes their beliefs (priors) in light of new in­
light of new evidence, or turns a blind eye, and instead conducts ex­
formation. The quintessential example is that of perception in either
periments (makes actions) that produce expected results (Friston and
dark or well-lit contexts. In the dark, visual input tends to be awash with
Frith, 2015). Under this account, actions are reflex arcs that unfold to
inconsistency and low definition, and thus prediction errors have low
create an experience that is consistent with an expected state of sensory
precision and are more likely to be ignored. On the other hand, in
affairs. Returning to our earlier example, organisms have certain stub­
daylight the sensory input is clear and reliable, and thus even a sur­
born expectations regarding fluid levels. If those expectations are not
prising visual event will be registered because it has high precision. And
met, a strong prediction error is incurred in the form of thirst. Once a
paying attention to a blurry object in our periphery (is it a mug?) can
certain threshold is reached, the organism generates a prediction
incur more precision to any incoming surprises (a teacup!). Mechanisti­
regarding a series of sensory and proprioceptive states that eventuate in
cally, paying attention to a particular sensory event is proposed to in­
an appropriate fluid to weight ratio. By reducing the difference (pre­
crease the synaptic gain of the cells that are encoding the prediction
diction error) between this prediction and the current sensory input, the
error (Feldman and Friston, 2010; Smout et al., 2019). Thus, attention is
organism will find water and regain its balance.5 Like the imperative to
said to turn up the “volume” (Clark, 2013, p. 22) of the input.
stay hydrated, modeling of the world is primarily in the service of utility
To risk over-stretching the function of attention slightly: the more
rather than fidelity: “The brain is in the game of predicting the world,
attention that an event receives, the more real it is. If a change in belief
but only as a means to the end of embodied self-preservation” (Allen and
occurs, it is because new information is believed to be veridical and can
Friston, 2018, p. 12).
be trusted (i.e., has high precision). And since attention is expected
It should be noted that active inference, although directed at con­
precision, then attention modulates reality-correspondence, ‘realness’,
firming predictions, is also critical for model revision because action
or “felt confidence” in input (Carhart-Harris and Friston, 2019). This
allows the brain to generate its own sensory input to test hypotheses.
reality-shaping effect of attention may be one reason that it plays such a
Crucially, the hierarchical and temporally deep nature of generative
key role in most meditation traditions. Preempting later sections, it is
models in the human brain permits that we can also think about actions
interesting to note that in certain meditations, attention must eventually
and their potential consequences without performing them (Friston, 2018).
be released in favor of a form of bare or non-preferential attention, and
Thinking, decision-making, and guided attention are thus kinds of
in yet other meditation practices of the non-dual category, attention is
mental actions (Metzinger et al., 2017; Spratling, 2016). They allow us to
released altogether (Dunne, 2011).
disembody from the present moment flow of sensory data in order to
covertly entertain possible, but non-existent states, i.e., counterfactual
hypotheses (Metzinger et al., 2017). This counterfactual cognition is 2.4. The inferred hierarchical self
thought to be in the service of allostasis—of predicting future states that
minimize expected free-energy under different scenarios (Corcoran Predictive processing accounts of the self are in the early stages
et al., 2019).6 And since all predictive processes are driven by past ex­ (Milliere and Metzinger, 2020), and there is still not widespread
periences, then higher cognition is similarly conditioned by past mental agreement among scientists on a definition of the self (Fingelkurts et al.,
experiences. That is, learning is also a pervasive feature of thought 2020). Nevertheless, assuming a predictive brain, we can draw some
(Perlovsky and Ilin, 2010). tentative conclusions. First, like all other aspects of mind, the self must
This perhaps uniquely human ability (Suddendorf and Corballis, also be a construction, built out of hierarchical models driven by past
2007) to project into the distant past and future is the creative force experience. Indeed, according to Friston (2018) and others (e.g., Deane,
behind the complex counterfactual trees that make up higher cognition. 2020) possessing a self-model is a natural consequence of active infer­
It may be humanities greatest asset in the service of survival (Bulley ence and prospection: One cannot predict the sensory outcomes of future
et al., 2016), but it may also underlie much of human suffering as it actions without representing oneself in those actions as a hidden cause
allows us to think about what is not happening (Killingsworth and of changes in sensory input. For example, picking up a glass of water
Gilbert, 2010). We may imagine many possible future scenarios—e.g., requires that we have a model of our body as an intentional agent who
being unsuccessful, or of ill-health—that we want to explicitly avoid and can pick up a glass of water. And indeed, we must have a model for the
fact that we are an agent that needs such a thing as water.7 This

5
Clearly, thirst is a rather high-level construct used to explain our intero­
7
ceptive signals and dispositions to drinking something. One can read "thirst" Note that picking up a glass of water entails the realization of a complicated
here as interoceptive signals, such as hyperosmolality of blood. course of action or plan that unfolds over several seconds. It is this planning
6
Heuristically, planning under deep temporal models means that you have that provides the evidence for - or is most parsimoniously explained by - the
your eye on the future. Imagine driving a car and think about where you are hypothesis that "it is me pursuing this course of action". This can be contrasted
looking, and how you are driving. Invariably, you will be looking - and steering with an autonomic reflex to dehydration, such as the release of antidiuretic
- pre-emptively, with a focus many meters in front of you and seconds (in some hormone. Later, we will consider the fundamental difference between low-level
cases minutes) into the future. Contrast this with being a passenger, passively homeostatic reflexes - that do not involve anticipation - and allostatic behav­
enjoying the passing scenery in the moment. iors, which do.

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self-modeling further endows the organism with the ability to consider caused by the environment), by comparing the incoming sensory input
itself in different future scenarios (i.e., entertaining counterfactuals: I’m to action-based predicted sensory input. Thus, self-awareness neces­
thirsty, but I could drink water, or tea). Changes to the sense of self, as sarily relies on models with temporal depth, that are capable of inferring
seen in virtual reality, psychopathology (Sterzer et al., 2018) or as the (not yet present) consequences of actions.
induced by drugs (e.g., psychedelics (Millière et al., 2018; Timmermann
et al., 2018), are usefully accounted for in predictive processing by 2.5. Fact free learning and insight
aberrant priors and precision-weighting (Adams et al., 2013; Corlett
et al., 2016; Sterzer et al., 2018), although the mechanisms may vary In the above we discussed the different roles that attention (i.e.,
depending on the specific case. If subjective experience—including precision weighting) and active inference (i.e., mental/physical actions)
therefore any self-models (Blanke and Metzinger, 2009)8—is inferred play in the revision of beliefs (priors). However, there is another way to
through Bayes-optimal inference under the predictive processing refine generative models that does not involve active inference or novel
scheme, the existence of aberrant self-perceptions is not surprising. sensory input, known as fact free learning (Friston et al., 2017). Aha!
The second implication is that the self is itself hierarchical in nature, moments or insights instantiate fact free learning because they involve
a prospect recently substantiated in a neurophenomenological study in the discovery of a solution, idea, or perspective without new informa­
meditators (Fingelkurts et al., 2020). Gallagher (2000) made the now tion. For example, we might unexpectedly discover a solution while
well-known distinction between a narrative and an experiencing self. The taking a shower or while engaged in another task (Laukkonen and
narrative self is embedded in our thoughts and includes our stories about Tangen, 2017; Laukkonen et al., 2021a; Metcalfe and Wiebe, 1987;
the past, the future, and all our self-referential knowledge and beliefs. Ovington et al., 2018). Moreover, experiments show that such insights
On the other hand, the experiencing self refers to our awareness of are usually correct (indicative of refinement, Salvi et al., 2016) and can
bodily sensations and events occurring in the present moment. The change subsequent beliefs (Laukkonen et al., 2018, 2020a, 2021b).
narrative self is perhaps neurally instantiated by the Central to the idea of fact free learning is that insights arise because
default-mode-network (DMN; Raichle, 2015), which is associated with the brain continues to refine and compress models through Bayesian
key features of high-level cognition, especially mental time-travel model reduction (Friston et al., 2016). Bayesian model reduction entails
(Østby et al., 2012) or more basic forms of counterfactual thinking finding simpler and more parsimonious models using only prior beliefs
(Van Hoeck et al., 2013). Indeed, Carhart-Harris and Friston (2019) (i.e., not using sensory outcomes, Friston and Penny, 2011). This process
propose that “…the human DMN can be considered to sit at the top of refinement is comparable to the “…physiological processes in sleep,
end—or center—of a uniquely deep hierarchical system…”. The expe­ where redundant (synaptic) model parameters are eliminated to mini­
riencing self is likely instantiated by task-positive and interoceptive mize model complexity” (Friston et al., 2017, p.2638). As models un­
networks (that are anti-correlated with the DMN), including executive dergo refinement and selection—thus making them more parsimonious
and control areas in the prefrontal cortex and anterior cingulate cortex explanations of sensory experience—they can also engender new dis­
(Fox et al., 2016) as well as the anterior insula (Seth, 2013) and other coveries, such as the discovery of a new perspective (generative model)
subcortical regions associated with homeostatic functions (Damasio, that permits a novel insight (or inference, Friston et al., 2017).
2012). Friston et al. (2017) suggest that fact free learning may not only
Within the predictive processing account, temporally thick processes occur during sleep but also result from reflection (or introspection), both
and therefore the narrative self is placed higher in the predictive hier­ explicit and implicit: “…Having acquired data, the “good scientist” re­
archy (Carhart-Harris and Friston, 2010). On the other hand, sensory flects on what she knows (and perhaps sleeps on it), implicitly testing
and interoceptive input and therefore the experiencing self would be plausible hypotheses of a progressively simpler (less complex and less
lower in the hierarchy (temporally thin, Friston, 2008). There may also be ambiguous) nature that could provide an accurate account of the data at
a minimal form of self even lower in the hierarchy, such as the hand” (p. 2666). The connection between fact free learning, insight, and
first-person perspective itself, but this is still debated (Blanke and Met­ meditation is therefore straightforward. Meditation is in many ways the
zinger, 2009; Sebastian, 2020). Moreover, in recent years experiments embodiment of fact free learning, by virtue of its emphasis on stillness
and a growing database of personal accounts are leading many re­ (both in body and mind) or in-active inference, which may trigger some
searchers to accept the existence of self-less states (see Milliere and analogous physiological and synaptic processes as sleep (Friston et al.,
Metzinger, 2020 for a special issue). It is also worth mentioning how a 2017). Moreover, meditation can induce extraordinary, novel mental
minimal or basal form of self might arise. As alluded to earlier, experiences (“input”), that cannot easily be accounted for by existing
self-modeling may be intimately tied to action, because one cannot models, increasing their uncertainty and necessitating revision. Thus,
model one’s own action pathways without modeling oneself as a hidden although we argue that meditation practice in essence reduces coun­
cause in the world. Simply put, the brain needs to model a ‘self’ in order terfactual abstract processing, it is simultaneously an opportune
to predict future states that the ‘self’ might inhabit. Along this line of moment for model revision and selection as the brain—despite the
thought, Friston (2018) suggested that self-awareness arises whenever reduced activity of body and mind—may continue its prerogative of
an organism generates predictions about the consequences of its actions, hierarchical prediction-error minimization via internal hypothesis
and thus aims to minimize the expected surprise resulting from those testing: “…much like a sculpture is revealed by the artful removal of
actions. In this view, the mind comes into being when self-evidencing stone” (Friston et al., 2017, p. 2669). The prospect that meditation en­
has temporal thickness or counterfactual depth. Similarly, it has been genders insight is also at the very foundation of (for example) classical
proposed that self-experience arises from self-specific processes that are Theravada Buddhism and vipassanā (insight) meditation practice, which
intrinsically related to the organism’s own actions (Christoff et al., aim to permit specific insights into the workings of one’s mind, dis­
2011). That is, only through action can the organism dissociate between cussed further below.
self (sensory changes caused by oneself) and non-self (sensory changes
3. Meditation

8 It is now worthwhile to return briefly to our central thesis in light of

In the vast literature on ‘the self’, there are important differences between
for example Gallagher’s (2000) experiencing self, Blanke and Metzinger (2009)
the previous sections. Our core proposal is that meditation gradually
minimal self, Seth’s (2013) embodied self, and yet other conceptions (e.g., reduces the temporal depth of processing9 in the predictive hierarchy by
Zahavi, 2017). Nevertheless, for the purpose of our model each of these con­
ceptions represent a clearly more basal form of self than that which is related to
9
our self-narratives. See Section 2.1: A hierarchy of expectations.

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bringing the practitioner more and more into the here and now. This meditation increases the precision-weighting of one source of present
process gradually prunes the counterfactual tree, reducing the brain’s moment sensory experience, and thereby reduces the frequency of mental
tendency to abstract temporally thick predictive models. Ultimately, processes that rely on deep temporal models. By confining experience as
since self-specific processes imply temporal depth of processing (Friston, much as possible to one prediction (e.g., breath sensations), FA auto­
2018), being fully immersed in the here and now may also occasion a matically encourages less habitual ‘grasping’ of other predictions (such
radical shift in one’s ordinary sense of self-consciousness. Moreover, as thoughts), and reduces their appearance (as their relative precision-
meditation may also foster fact free learning (insights), where one’s weighting is diminished). Novice practitioners may have trouble sus­
models are refined without active inference. taining their attention at one point of focus, reducing the precision
To prepare for a more nuanced overview of our model, in this section assigned to the corresponding sensory signals, providing space for
we briefly describe three categories of meditation most studied in mental distractions (e.g., mind wandering). Advanced practitioners may
contemplative science, that also represent three main classes of decon­ reach a kind of ‘focused homeostasis’ once distracting counterfactual
structive meditation in Buddhism (for much more detailed reviews of hypotheses become sufficiently infrequent. Another natural conse­
these practices see, Dahl et al., 2015; Dunne, 2011; Lutz et al., 2007; quence of restricting awareness to one “object” of experience is that with
Lutz et al., 2008, 2015). These three categories (FA, OM, and ND) are more advanced practice, one is no longer engaged primarily in the
umbrella terms that do not capture the full diversity found in Buddhist narrative self, and instead is in a less abstracted, present moment mode
theories and practices. Therefore, our model should be seen as an um­ of experiencing.
brella framework that integrates three widely practiced styles of medi­ As noted earlier, expected precision prescribes reality-
tation. Moreover, similar practices are found outside of Buddhism, for correspondence, ‘realness’, or “felt confidence”, so the up-weighting of
example in Advaita Vedanta and Sufism (Dahl et al., 2015). The prac­ precision for the input of the FA object (e.g., the breath) should also lead
tices are also not always clearly distinct and multiple techniques may be to a relative down-weighting of predictions higher in the hierarchy (e.g.,
used throughout one’s training (Lutz et al., 2008). In the Buddhist thoughts), and this in turn may reduce the subjective realness of dis­
tradition, ND meditation (Lutz et al., 2006) is particularly emphasized tracting thoughts and feelings and provide a first step towards der­
within Mahayana and Vajrayana Buddhism (so-called non-dual tradi­ eification necessary for more advanced practices (Lutz et al., 2015).
tions). So far, most research on ND meditation has focused on Maha­
mudra and Dzogchen from the Vajrayana tradition (Antonova et al., 3.2. Open monitoring
2015; Josipovic, 2010).
As we describe each meditation technique, we also highlight key Open monitoring (OM) meditation may follow after one’s mind is
ways in which they may affect predictive processing, though these notes sufficiently anchored in the present moment through FA. The practi­
will be made more formally in the next section. Our central hypothesis tioner may then begin to gradually open the scope of attention to the
here is that each meditation style gradually draws predictive processing broader field of experience: A kind of ‘open monitoring’. Particularly in
closer and closer to the here and now (i.e., less abstract hierarchically Theravada Buddhist schools of meditation, FA practice is often used to
deep processing).10 prepare the meditator to practice OM, which is believed to permit
deeper insights into the nature of the mind (Lutz et al., 2007), namely:
impermanence (aniccā), non-self (anattā), and suffering (dukkha).
3.1. Focused attention
During OM, one does not sustain attention to an explicit object of
experience. Instead, in an open and receptive way one allows whatever
Focused attention (FA) meditation is often practiced when one be­
arises in experience to come and go: sensations, thoughts, or feelings, or
gins meditation. It involves the explicit focus on a particular aspect of
other states of mind, without judgement or evaluation. The focus of this
one’s present moment sensorium to the exclusion of everything else. The
practice is in the cultivation of meta-awareness and in dereification from
target of one’s attention is often the breath, but ultimately any object in
the contents of experience. In other words, everything that appears in
present moment experience, like one’s feet while walking, can serve the
experience is treated equally from the perspective of a non-judgmental
same purpose. The primary aim of this practice is to stabilize one’s
observer. OM may initially require some effort to maintain awareness
attention in the present moment. When thoughts or mind-wandering
in the here and now, and explicit attention may be briefly given to the
episodes arise, attention is guided back to the sense object. Thus, FA
different events that appear in experience (e.g., through a practice of
also involves monitoring or meta-awareness of the quality of attention
labeling the contents of experience). Advanced practitioners are said to
on the object. With practice and the development of meta-awareness it is
be able to effortlessly observe experience as a whole, without being
said to become easier and eventually effortless to sustain attention on
‘caught’ by thoughts, emotions, or anything else that arises in one’s
one point of focus in the present moment. Crucially, FA may help to
sensorium. This way, mental events “lose their representational integrity
develop the first steps of dereification that are foundational for more
and are experienced simply as mental events, situated and embodied
“advanced” practices: the ability to discover that all of one’s experience
within a field of sensory, proprioceptive, affective, and somatic feeling
is a process rather than a true reflection of reality (Lutz et al., 2015). The
tones” (Lutz et al., 2015). Thus, in OM, awareness of the background of
development of meta-awareness and dereification permit an easier
experience further comes to the foreground, as one develops the ability
transition to more advanced practices in which these aspects are further
to rest in a stable sense of “pure” experiencing.
developed (Lutz et al., 2015), as discussed further below. Yet, experi­
Although oscillation between FA and OM may often occur during
enced practitioners may continue to practice FA at the beginning of a
practice, unlike the directed focus of FA, OM treats all arising signals
meditation period to initially stabilize attention, and indeed may
non-preferentially (e.g., a thought, an emotion, or a sensation). Thus,
continue to practice FA for other reasons, such as the achievement of
from a predictive processing perspective, any content of experience is
deep states of tranquility (Wallace, 1999).
assigned equal precision, and consequently low precision in relative
From a predictive processing perspective, we propose that FA
terms. Crucially, the goal of OM is not to stop experiences from arising.
Instead, one reduces ‘grasping’ by quickly letting arising experiences
10 (predictions) go without confirmation, by maintaining a restful but alert
Later, we will see that increasing the precision in the lower (sensory) levels
of a hierarchy necessarily entails a decrease in (relative) precision deep within state of non-judgmental observing. Thus, OM continues to reduce the
the hierarchy. In other words, meditation re-balances the hierarchical deploy­ precision and temporal span of predictions arising in experience. As
ment of attention or precision - from higher to lower levels of hierarchal pro­ restful non-judgmental observing increases, the system may begin to
cessing. Advanced stages of meditation may release precision-weighting experience a kind of ‘pure’ sensing without evaluation. This ‘pure
altogether. experiencing’ is conceivably temporally prior to evaluations of the

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sensory experience. For example, sensations in the knees or back during component of this practice is that one aims to discover an awareness that
sitting meditation may occur prior to the evaluation of the experience as is unchanging regardless of what happens in experience. Metaphorically
“painful”. This is what is believed to allow practitioners to sit for the “ground of all experience”. Some historians propose that this style of
extended (sometimes many hours) at a time without moving.11 Thus, meditation was developed later in time than FA and OM meditation,
non-judgmental experiencing could be said to be the natural state of the based on emphasizing the idea that there is an awareness that is
system at a lower level of the hierarchy. We therefore propose that as the “beyond” the subject observing experience that is implicated in FA and
frequency and temporal span of predictions such as thoughts, emotions, OM (Dunne, 2011; Gyatso, 2010). From the perspective of the ‘non-dual’
and sensations, decreases, then a hierarchically lower level of the pre­ discovery, the duality between subject and object is itself a conceptual
dictive hierarchy (experiencing prior to evaluation of experiencing) model constructed from past experience. Clearly FA and OM still have
dominates. This state is different from FA since no experience is given embedded within the practice the duality between an (unconditional)
preferential precision-weighting, and thus ‘attention’ becomes ‘bare’ observer and objects that are observed. Thus, as a final ‘release’ of any
rather than ‘object-oriented’. abstraction away from the here and now, in ND meditation the idea that
Under this scheme, the novice OM practitioner experiences more there is a distinction between self and objects of experience also falls
frequent and temporally extended predictions with higher average preci­ away, for example, by realizing that subject and object always arise
sion than the experienced OM meditator. The more precision the prediction together in experience. This results in a state of awareness in which there
errors are assigned, the more likely the corresponding content is to ‘eclipse’ is no background or foreground of experiencing, that is hence devoid of
one’s mindful (non-judgmental) observation. As expertise increases, the concepts (self, objects), intentionality or the experience of time and
temporal span, precision, and frequency of predictions decreases, making space, i.e., a state in which even the most basic constructs of cognition
more ‘room’ for background awareness. With even further practice, expe­ allegedly no longer persist.
riencing may lose its evaluative quality entirely. The expert OM practitioner It is against this awareness that all cognition is said to arise. It is
therefore should eventually come to rest in a non-judgmental experiencing somewhat paradoxical then to talk about a ‘non-dual practice’, since the
that we propose is earlier in the predictive hierarchy. term ‘practice’ itself implies a duality (someone who is practicing
It is also plausible that the practice of non-judgmentally observing and something). Thus, one way to understand the nature of non-dual prac­
releasing arising predictions could permit epistemic changes to the system, tice is as follows: creating the conditions that reduce ordinary cognition that
in line with classical Buddhism (Bodhi, 2011a, 2011b) and fact free normally ‘hides’ non-dual awareness. Such a practice is exemplified in
learning (Friston et al., 2017). If all generated predictions (thoughts, “open presence” and Dzogchen styles of practice within Tibetan Bud­
feelings, sensations) are continually seen as appearing and disappearing, dhism (Dahl et al., 2015) and Shikantaza or “just sitting” within the Zen
it would be logical to conclude—have the insight—that they are imper­ Buddhist tradition (Leighton, 2004). There are also other even older
manent (aniccā).12 Moreover, if one sees that all predictions are quickly practices with Hindu origins such as self-enquiry in Advaita Vedanta
interpreted by the system as pleasant or unpleasant leading to craving or (Dahl et al., 2015) that utilizes questions such as “who am I?” that point
aversion respectively (i.e., later in the hierarchy), then one would see the attention towards the ‘subject’ of experience so that its absence may be
suffering (duhkha) inherent in much of experience. Finally, if arising discovered (Nisargadatta Maharaj, translated talks by Frydman,
predictions are not under control (i.e., appearing spontaneously), then it is 1973).14 For a collection of case-studies describing non-dual experiences
also perhaps recognizable that they—including all embodied sensations see Metzinger (2020), and for a detailed review see Josipovic (2019).
and narrative self-centered thinking that are usually ascribed self-­ Non-dual meditation, and particularly the qualities of the non-dual
hood—are not self-induced, i.e., do not have any consistent unchanging experience, is perhaps the most challenging to characterize within the
self-like character (anattā). In other words, OM by making earlier levels of predictive processing framework.15 However, since all mental experi­
the predictive hierarchy perceptible may reveal that the embodied and ences are constructed through a process of abstraction away from the
narrative self are just processes rather than concrete entities. Buddhist here and now, then if one were truly to be in the present moment—i.e.,
insights may therefore be seen as new priors engendered by OM practice not constructing models with temporal thickness—then something akin
possibly as a result of Bayesian Model Reduction or fact free learning. to a non-dual experience would logically arise. That is, any mental ac­
tivity that relies on active inference should disappear, including activity
related to self-awareness (Friston, 2018; Limanowski and Friston, 2020;
3.3. Non-dual
Metzinger, 2020) and time (Berkovich-Ohana, 2017). To draw this
conclusion, we must assume that some minimal form of experience is
Non-dual (ND) meditation is of growing interest to scientists (see for
still possible without contents or sense of self, though it may16 raise
example, Dunne, 2011; Josipovic, 2010; Metzinger, 2020).13 The key
certain philosophical conundrums. As noted by Limanowski and Friston
(2020, p. 2), “How could one have a conscious experience – and able to
11
report on it afterwards – in the absence of any awareness of oneself (as
This continued ‘in-active inference’ induced by physical stillness may also
having the experience)?”.
gradually reduce any sensory evidence that one is a skilled actor or agent,
In search for a naturalistic explanation of ND experiences, Metzinger
which may begin to deconstruct the very notion of one’s self.
12
Evan Thompson (2020) has also argued that meditation involves the
(2020) developed the concept of minimal phenomenal experience and
development of new concepts, such as ‘moment-to-moment arising’, ‘not-self’, proposed that non-dual experiences are a Bayesian representation of
and ‘impermanence’, concepts that then restructure one’s experience. From the
perspective of fact-free learning, novel priors such as ‘impermanence’ may cast
a simpler and more parsimonious account of the behavior of thoughts, feelings,
14
and sensations, thereby reducing model complexity. See also Ashtavakra Gita (Byrom, 1990 translation), perhaps the oldest
13
The non-dual state was also described early on in Western Psychology. In non-dual text with Hindu origins.
15
1890 William James coined the term ‘sciousness’, which he described as an It is worth noting that progression from FA, to OM, to ND is not guaranteed
awareness preceding con-sciousness that is without subject or object (Bricklin, for individuals embarking on meditation practice. It is quite possible that there
2003). Other descriptions of non-duality are present in Hinduism as well as exists a ‘talent’ for meditation that may mediate whether one is capable, or how
western neo-Platonic and Christian traditions. James also described an expe­ quickly one is capable, of passing through the stages of meditation. Determining
rience that has non-dual qualities as follows: “During the syncope, there is such talent is a fruitful path for future research.
16
absolute psychic annihilation, the absence of all consciousness; then at the Whether this is a genuine philosophical conundrum is questionable (since
beginning of coming to, one has at a certain moment a vague, limitless, infinite it’s not inherently paradoxical that memories should form without selfhood, e.
feeling – a sense of existence in general without the least trace of a distinction g., semantic memories). Moreover, it’s possible that transition periods away-
between the me and the not-me.” (James, 1890/1950, p. 273) from and into non-dual states afford memory encoding.

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intrinsic arousal. Indeed, maintaining an optimal level of arousal or 4. A unifying framework: the many-to-(n)one model
alertness is central to many meditation practices and may support the
maintenance of appropriate sensory precision estimates. This proposal Having now laid most of the groundwork for our model, in this
fits with work showing that arousal levels causally determine one’s level section we provide two illustrations and with them aim to capture the
of consciousness and critically enable cortical activity and therefore key components of the theory. In Fig. 2 below, we illustrate the effects of
cognition (Laureys et al., 2009). According to Metzinger (2020), an FA, OM, and ND meditation specifically as they relate to the depth of
inner representation of arousal would be expected to possess the char­ processing in the predictive hierarchy. Then, in Fig. 3, we illustrate with
acteristics of non-dual awareness described by practitioners, including: more nuance how the different meditations may affect the time-course
“…a complete absence of time-representation and any form of sensori­ of prediction and precision at different levels of the hierarchy.
motor or high-level cognitive content. Further, there would be an The above figure provides a broad illustration of how each medita­
absence of low-level embodiment in the sense of spatiotemporal tion technique gradually decreases abstraction in the predictive hierar­
self-location, interoception, and affective background, as well as of chy. Although we have delineated three levels of the hierarchy to
higher levels of selfhood like attentional control and cognitive agency.” correspond to the three meditation techniques, the hierarchy is of course
(p. 36). Although there is an absence of representations of self, space, far more multilayered. For instance, within sensations there is also a
and time, there would nevertheless remain an experience of wakefulness hierarchical constructive process, whereby two-dimensional impres­
and the potential for cognition. The described model is as yet speculative, sions are built into more complex shapes through learned statistical
and further research is necessary to test this hypothesis. regularities grounded in past experience (Friston, 2005; Serre, 2014).
Theoretically, the ND state ought to be “empty” even of the very Thus, intensive and prolonged FA practice may also be able to break
possibility to attain conscious insights that characterize OM meditation, down sensations into its earlier stages of construction in the hierarchy.
assuming that the system is no longer constructing temporally deep Thinking is also likely hierarchical, ranging from simple conceptuali­
models. This appears consistent with perhaps the most popular zation of an object (e.g., noting the observation of a cup), to
Mahāyāna (ND) Buddhist scripture, known as the Heart Sutra, which for task-unrelated and disembodied mind-wandering.
example states—seemingly transcending the insights of OM practi­ We also intentionally did not specify the nature of the subject-object
ce—that there is “…no truth of suffering, of the cause of suffering, of the distinction because what precisely constitutes the ‘subject’ of experi­
cessation of suffering, or of the path. There is no wisdom and there is no ence, whether it be a unified proprioceptive model (Friston, 2005; Serre,
attainment whatsoever… And, thus, he passes far beyond confused 2014), or something more basal like witness consciousness (Albahari,
imagination. And reaches Ultimate Nirvana.” (To et al., 2000). The 14th 2009),17 is still debated. Nevertheless, drawing on Friston (2018), we
Dalai Lama also noted that the Mahāyāna tradition emphasizes empti­ suggest that the experience of being a subject as separate from objects
ness (śūnyatā) of all phenomena (including Buddhist teachings and laws, (that is self-consciousness but not consciousness per se, see Deane, 2020;
or Dharmas, Gyatso, 2010) whereas classical Theravada Buddhism em­ Metzinger, 2020) occurs due to predictive models aiming to reduce
phasizes the cessation of suffering, or insight. While we maintain that expected uncertainty. Thus, by being truly present, it may be possible
during non-dual awareness conscious insights seem logically impossible, that there occurs a release of any expectations of future states, and thus a
discovering that everything is empty is a consistently reported insight, ‘non-activation’ of the most basal self-model and duality itself. Also, if
that allegedly qualitatively alters one’s subsequent experience of reality. the current moment is no longer situated with respect to the previous
This may suggest that model reduction can also occur during states of and the next moment in time, the experience of timelessness is a logical
minimal temporal depth (cf. in sleep) or happens relatively quickly after consequence.
coming out of the non-dual state. Despite ‘experiential emptiness’ some Strikingly consistent with the continuum of decreasing abstraction in
forms of fact free learning may continue (e.g., selecting between model x our framework, in a recent meta-bioinformatics study of 17,000 exper­
and equally probable model y because model x is likely to lead to the iments and approximately 1/4 of the fMRI literature, Taylor et al. (2015)
least surprising outcomes, Friston et al., 2017). used connectivity models and a data-driven approach to reveal “…an
It is important here to note that, although we have placed FA, OM, objective hierarchical landscape of cognition in the brain, with awareness
and ND practice on a continuum of reducing counterfactual or deep at its structural core, and all results defined solely by a computational
temporal processing, we are not claiming that any particular practice or analysis, largely devoid of human bias” (p. 11, emphasis ours). More­
tradition is superior. The interconnectedness and progression of practice over, ~500 subjects intuitively ranked the behavioral tasks used in the
highlights that they are in many ways inseparable, and may have analysis on a spectrum from concrete to abstract, and this ran­
different effects that might be perceived as valuable or not depending on king—somewhat astonishingly—mirrored the objective
the tradition. For example, whether self-less states are beneficial or physiologically-based ranking. Thus, indicating that the brains func­
detrimental has long been and still is debated within Buddhism tional hierarchy can be considered a process of abstraction further away
(Thompson, 2020), as well as in the scientific literature (Britton, 2019). from the core (awareness) followed by direct sensory input, and then
In classical Buddhism, subject-object orientation is not considered further abstraction in the hierarchy from there (e.g., conceptual
problematic (Dunne, 2011). Only in later non-dual Buddhist traditions, thought).
the aim became to eliminate the duality of a knowing subject and known An outstanding question following Fig. 2 is how precisely each
object. Generally, it is important for researchers to realize that Bud­ meditation technique reduces abstract processing. To this end, in Fig. 3
dhism is not monolithic. As a final caveat, the term non-dual has been below illustrates how each meditation type may change the frequency
used with some variability in the literature (Dunne, 2011; Fucci et al., and precision of predictions over time.
2018; Josipovic, 2010, 2019; Travis and Pearson, 2000). Our conception To our knowledge, what we have described is the first integrated
here is of the most ‘radical’ kind, wherein all possible distinctions in predictive processing account of FA, OM, and ND meditation styles.
experience have fallen away. There are likely many phenomenological
states that are less dualistic (e.g., mindful observation) and some that
feel non-dual (e.g., reflexive awareness, Josipovic, 2019). But by virtue 17
Albahari (2009) proposes that the Eastern construct of
of these states containing subjectivity and even the ability to know some
witness-consciousness “captures the essence of subjectivity”. The concept is
separate thing (e.g., reflexive awareness is believed to be recognizable
originally derived from the contemplative tradition of Advaita Vedãnta, and
even during normal states of activity) there is inherently some duality was described as follows by Gupta (1998) in his book The Disinterested Witness:
built into the experience that permits categorisation, perception, and A fragment of Advaita Vedãnta Phenomenology: “[it is] the basis for all knowing
action. [but] different from the object known. It is implied in every act of knowing. It is
the ultimate subject; it can never become an object of knowledge.”

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Fig. 2. In this schematic we illustrate two aspects of the many-to-(n)one model. The first and most foundational proposal is that meditation gradually flattens the
predictive hierarchy or ‘prunes the counterfactual tree’, by bringing the meditator into the here and now, illustrated in the left figure. Thus, meditative depth is defined
by the extent that the organism is not constructing temporally thick predictions. In the right figure, we dissect the predictive hierarchy into three broad levels. We
propose that thinking (and therefore the narrative self [NS]) sits at the top of the predictive hierarchy (Carhart-Harris and Friston, 2010, 2019). Sensing and
perceiving and therefore the embodied experiencing self [ES] sits below it (Gallagher, 2000; Seth, 2013). Finally, a basal form of self-hood characterized by the
subject-object [S/O] duality sits at the earliest level. FA brings the practitioner out of the narrative self and into a more experiencing and embodied mode of being.
Then, through dereification from present moment experience (including bodily sensations) OM brings the practitioner more into a state where contents of experience
are treated equally, and one is able to experience non-judgmentally (sensing without appraisal), but even in very advanced states, a subject-object duality remains.
During OM, certain epistemic discoveries or insights about the nature and behavior of generative models may occur. Finally, through ND practices the subject-object
distinction may fall away and the background or “groundless ground” of all experience—awareness itself—can be uncovered. Another way to characterize this
process is as follows: FA employs regular (conditional) attention to an object of sensing, OM employs bare (unconditional) attention, and ND practice employs reflexive
awareness that permits the non-dual witnessing of the subject-object dichotomy and finally pure or non-dual awareness by releasing attention altogether.

Although each meditation is proposed to uniquely modulate predictive inherited through evolution about physiological allostasis ought to ‘kick
processes, they nevertheless exist on a continuum where each strategy in’ and drive behavior towards survival, albeit in extreme cases.18
gradually breaks down increasingly ingrained expectations. Yet, one
may wonder if true present-momentness is ever possible, given that also
in the ND state, vital bodily parameters must remain within bounds. 4.1. Predictive processing & meditation: A nascent field
Thus, we propose that the ND state is characterized by a collapse of
predictive processes that possess temporal depth and involve minimi­ “…it is easy to see that the FEP [Free Energy Principle] framework
zation of expected surprise. If one is no longer making any predictions appears optimally suited for the scientific investigation of contem­
about the next moment in time, then there is also no reference for time plative practices. In fact, it ties together in a coherent theoretical
(i.e., past or future within which to define the present) or a continuous scaffold the core meditative notions of attention (top–down
sense of self (i.e., no construct of self that was, is, and will be). Under this deployment of precision weighting), the conditioning power of
view, vital homeostatic predictive processes that operate at low levels of habitual self-related patterns of thought and behavior (priors), and
the hierarchy and do not elicit subjective experiences may continue, the embodied nature of cognition and emotion (interoceptive infer­
such as the maintenance of body temperature and blood circulation ence).” (Lutz et al., 2019, p. 167)
within necessary bounds. Yet, obviously, if one would stay in the ND
Several theoretical proposals have been put forward in recent years
state too long (as in the dark room), one would naturally end up dead.
about how meditation may affect predictive processing, although none
Ultimately, humans, like any living creature, have evolved to occupy a
of these distinguished between effects of different styles of meditation
specific econiche that allows them to maintain their boundary, to not fall
(although the existence of possible differences were acknowledged by
into entropy, which requires for example expectations to eat or drink.
both Lutz et al., 2019 & Pagnoni, 2019). In a published conversation on
Expert meditators report that it is possible not to experience hunger or
predictive processing and meditation between Pagnoni (a neuroscien­
thirst (indeed any bodily experience whatsoever) during meditation,
tist) and Guareschi (an Abbot of a Zen monastery, Pagnoni and Guar­
which makes sense from our perspective given the counterfactual nature
eschi, 2017), the role of attention and bodily posture was emphasized as
of allostatic processing in hierarchical models. To illustrate with the
important ingredients to make generative models more susceptible for
example of hunger, “…hunger does not simply reflect an inference about
revision in light of new input. More recently, Lutz et al. (2019) framed
hypoglycaemia but the belief that if I act in this way, I will avoid (sur­
FA meditation in predictive processing terms as corresponding to “the
prising) interoceptive (low blood sugar) cues. This reflects the quintes­
selection of a policy that includes the mental action of setting a high
sentially counterfactual nature of allostatic processing in hierarchical
precision for the sensory prediction errors associated to the chosen
models.” (Pezzulo et al., 2015, p. 26). As we experience the world not
attentional target and the prescribed bodily posture”. They furthermore
just with our bodies, but because of our bodies, ultimately, expectations
describe the shift from a state of focus to mind wandering as involving

18
In the famous case of Ramana Maharshi, it is said that he was so absorbed in
ND awareness that “…he was completely oblivious of his body and the world;
insects chewed away portions of his legs, his body wasted away because he was
rarely conscious enough to eat and his hair and fingernails grew to unman­
ageable lengths… [a return to a normal physical condition] was not completed
for several years.” (Godman, 2017). When he was discovered, food had to be
placed in his mouth to prevent him from starving.

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Fig. 3. Here we illustrate the precision and frequency of predictions at different levels of the predictive hierarchy during mind wandering, FA, OM, and ND. Blue
rectangles represent levels of the predictive hierarchy, with counterfactually deeper and later levels represented at the top (e.g., mind wandering and the narrative
self), task-relevant thinking in the middle, and the bottom rectangles represent earlier, temporally thin levels (e.g., present moment sensory experience). Ovals
represent the predictions active in one’s experience. The redder the oval the higher the precision-weighting of the prediction. The location of the oval in a specific
rectangle represents a different prediction of the same level of the hierarchy. For example, during FA meditation, one engages attention (increases precision) of a
specific prediction at earlier levels of the predictive hierarchy (e.g., the breath). With practice, one can sustain attention on the same prediction for a longer period of
time while decreasing the frequency and relative precision of predictions higher in the hierarchy. When one practices OM, different predictions will still arise in
experience but are assigned lower precision, as illustrated by smaller and lighter ovals. With ongoing practice of OM, predictions arise less frequently and become less
‘sticky’, thus also disappearing faster. Increasingly experiencing without appraisal (an earlier level of the predictive hierarchy) dominates as predictions, or contents
of experience, become less relevant and capture attention less. Finally, during ND meditation, the awareness inherent in experience becomes the foreground. In FA
and OM, predictions within experience are still the prominent event in experience. However, in the ND state, all contents of experience, as well as the subject of
experience, fall away, and only awareness (without background or foreground) remains. This is represented by the background of the rectangle becoming red instead
of blue. Note that for the FA, OM, and ND categories we have exemplified a relatively advanced practitioner. For a more novice meditator one can generally expect
longer, more frequent, and more variable predictions at higher levels of the hierarchy.25

two processes: a change in prediction from sensory input (e.g., breath) to of counterfactuals post-meditation by down-weighting the precision of
mental events (e.g., thought), and a corresponding shift in expected ingrained habits of mentation. Put simply, the state of meditation de­
precision higher in the hierarchy (e.g., from sensing to thinking). This creases counterfactual processing (as we propose), but the enduring
characterization is largely consistent with our account of FA meditation, result or trait of meditation may permit a more flexible and rich coun­
where the goal is to bring attention away from thoughts (predictions terfactual processing in daily life.
high in the hierarchy) via increasing expected-precision of a sensory To date, no distinctions were made regarding the way that different
object (lower in the hierarchy). styles of meditation may change predictive processing. Moreover, our
Lutz et al. (2019) further proposed that FA meditation is character­ model takes an important step by proposing a single mechanism that can
ized by inaction at multiple levels: the level of behaviour (sitting still), account for the effects of FA, OM, and ND: They progressively reduce
vision (e.g., keeping one’s eyes centrally directed), and thought (by abstract processing in the brain. We also suggest that when viewed as a
maintaining attention on a specific object). This non-action radically continuum of ‘hereness and nowness’, the purpose of these practices go
restricts active inference, and thus reduces the influence of prior beliefs beyond the regulation of cognition, attention, and emotion (as typically
and upweights the influence of sensory evidence. Indeed, past theorizing emphasized in the literature, e.g., Slagter et al., 2011) and instead
emphasizes that the strict bodily posture adopted in meditation is not emphasize the reduction of habitually generating predictions based on
arbitrary (Pagnoni and Guareschi, 2017; Pagnoni, 2019; Lutz et al., past experience. Like previous work, we also acknowledge the crucial
2019). Lutz et al. (2019) suggested that the posture aids focus by alerting role played by the embodied, holistic in-active inference of meditation
the meditator to mind-wandering whenever one “slouches”, thus elic­ that we think serves to prevent habitual predictions from arising in
iting a prediction error that brings the meditator back to the sensory experience. Our model also goes further to propose how the three main
object, functioning as a kind of bio-feedback device (Pagnoni, 2019). meditation techniques may gradually deconstruct self-related pre­
Pagnoni also recently connected another specific meditation technique dictions, unraveling increasingly basal forms of self-hood, until that
to predictive processing known as Shinkantaza, a form of Japanese (ND) which is even prior to self-modeling can be experienced. And finally, we
Zen meditation. Interestingly, and at first glance in contrast to our also provide a framework for understanding how certain key insights
model, Pagnoni suggests that this meditation practice increases the may arise through fact free learning, which may cascade a radical
counterfactual richness of processing. Noting that this is “paradoxical” revision of one’s generative model and key priors.
given the meditators focus on the here and now, the idea is that medi­
tation weakens ingrained prediction loops and this in turn permits one to 5. Key empirical predictions and support
entertain a broader set of counterfactuals (particularly outside of formal
meditation). Thus, while we propose that meditation itself “prunes the In this section, we delineate key empirical predictions that can be
counterfactual tree”, this pruning may be precisely what allows the derived from our many-to-(n)one model. As yet few studies have spe­
system to then embody a more flexible and variable—or more rich—set cifically examined how meditation may modulate predictive processing.

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Also, so far, most research has focused on the effects of FA and OM of an inferential process. Thus, being fully immersed in the here and
meditation on brain and mental functioning, possibly because these now—i.e., not constructing temporally deep models—it would theoreti­
meditative states can be applied to an external task more easily than the cally be possible for meditation to modulate the construction of painful
ND state. Therefore, we here selectively review some seminal studies for experiences. Consistent with this idea, Perlman et al. (2010) found that
initial evidence in support of our model and to illustrate how existing OM (but not FA) meditation leads to significantly lower ratings of un­
findings can be reevaluated within our framework. Given the nascent pleasantness for painful stimuli, but not of intensity. This finding also
field, our model is also forward looking and we hope that it will inspire makes sense under our framework where OM works to reduce the
many new directions for empirical work. temporal depth of processing to a more direct experiencing prior to
appraisal/judgment.19
Finally, in ND meditation, even processes that are temporally prior to
5.1. Meditation reduces the temporal depth of generative models and
appraisal/judgement, e.g., related to perceptual categorization or se­
corresponding mental processes
mantic processing, should disappear. Yet, what is exactly left in the ND
state is unclear (Srinivasan, 2020). Stimuli (e.g., a spoken word) may
Our core proposal is that the temporal depth of mental activity re­
still evoke responses in early sensory regions in a bottom-up manner, as
duces from FA to OM to ND meditation (Fig. 3). This first of all leads to
in coma patients (Morlet and Fischer, 2014; Qin et al., 2008), but they
the key prediction that (neural) activity should decrease across the
may no longer be responded to in a top-down manner by regions further
temporal hierarchy across meditation styles. This should ultimately
up the processing hierarchy (e.g., that bind features or derive word
affect any temporally thick mental process, including conceptualization
meaning). This would be in line with proposals that the ND state is
and the sense of self.
devoid of conceptual representational content, as even the conceptual­
First, as FA meditation brings about a shift from thinking to sensing
ization of e.g., a cup relies on past experiences with a cup and in­
by increasing the expected precision of one source of present sensory
corporates counterfactual elements regarding its future use (Dunne,
experience, engagement with temporally thick counterfactual pre­
2015; Metzinger, 2020). Yet, so far, few studies have examined the ef­
dictions (e.g., mind wandering, planning for the future) higher in the
fects of ND meditation, likely because one cannot ask meditators to
hierarchy should naturally be reduced. Indeed, one seminal study by
engage in an external task while in the ND state, since this would
Lutz et al. (2009) found that practitioners of a three-month meditation
immediately disrupt this state of in-active inference. Most studies have
retreat exhibited an increase in the temporal consistency with which the
looked at changes in “resting state” fMRI and EEG activity during ND,
brain responded to auditory tones presented in the attended ear during
reporting changes in rhythmic neural activity and connections between
FA meditation, that was accompanied by a reduction in reaction time
brain networks (Berman and Stevens, 2015; Josipovic, 2014).
variability, suggestive of a more stable focus of attention. Other studies
Yet, there is some evidence that meditation may affect even basic
have accordingly associated FA meditation with reduced
perceptual predictions from a study by Carter et al. (2005), which
mind-wandering (Levinson et al., 2014; MacLean et al., 2010; Mrazek
examined effects of extensive meditation experience on binocular ri­
et al., 2012), and decreased default mode network activity typically
valry. Binocular rivalry is the fascinating phenomenon that when two
associated with self-referential processing and offline thoughts (Fox
images are presented separately to each eye (e.g., a face and a house),
et al., 2016) proposed to lie at the top of the processing hierarchy
the observer perceives an alternating face or house image (and some­
(Carhart-Harris and Friston, 2010, 2019). These findings align with the
times a mix). Under the predictive processing framework (Hohwy et al.,
notion that FA enhances present-moment awareness of one source of
2008), the rivalrous perception occurs because the input violates the
sensory input, thereby logically reducing temporally thick processes
brains expectations that two different images can occur in the same
detached from the current environment.
spatio-temporal location. Thus, past experience prevents the perception
Next, OM meditation withdraws selective attention in favor of a
of the ‘true’ input, i.e., a coalesced face-house image. Moreover,
broad scale dereification from the contents of experience. Such non-
perception continues to switch between percepts because the unper­
judgmental experiencing, we have proposed, equates to a reduction in
ceived stimulus continues to trigger prediction errors until it leads to a
the relative expected precision of all contents of experience, resulting in
revision in the posterior hypothesis (and the cycle continues). Intrigu­
non-reactive awareness of whatever rises in experience. This should be
ingly, when Carter et al. presented binocular rivalry stimuli to Tibetan
reflected in reduced mental acting on events (e.g., judging, evaluating).
monks with extensive meditation experience, they found that one-point
In line with this, Slagter et al. (2007) found that after 3 months of OM
meditation (an advanced form of FA) reduced perceptual switch rates
practice under intensive retreat conditions, participants showed an
(including three monks who experienced a stable stimulus for the whole
enhanced ability to notice the second of two target stimuli (T1 and T2)
five-minute period!). From the predictive processing perspective, this
presented in close temporally proximity (i.e., a reduced attentional
makes sense if the meditators, through FA, increase the precision of the
blink). Moreover, this increase in T2 perception was brought about by a
prediction errors of the attended stimulus (thus, overpowering predic­
reduction in attentional clinging to the first target stimulus, as reflected
tion errors from the unperceived stimulus). Yet, more strikingly, the
by a smaller T1-evoked P3b, a brain potential associated with higher-
authors also found something highly unusual: One of the monks re­
order stimulus processing. These results make sense within our frame­
ported experiencing a prolonged so-called ‘mixed percept’. Under the
work: if each passing stimulus is assigned lower precision, then the first
predictive processing framework this suggests that the stubborn pre­
target is less likely to capture attention (be temporally deeply pro­
diction ‘two images cannot appear in the same spatio-temporal location’
cessed), permitting better detection of T2. Further evidence that OM
meditation reduces the construction of temporally deep models comes
from meditation studies on painful experiences. The experience of pain
is also a highly automatic inference. But, like other subjective experi­ 19
In the present framework, evaluation, appraisal and judgement can be read
ences, under the predictive processing framework, pain is the outcome as synonyms for inferring the most plausible policy to enact. Crucially, a sus­
pension of evaluation requires a loss of precision of policy selection. On this
view, OM meditation precludes precision at higher levels responsible for eval­
uating the affordances of an action; namely, any predictive processing that
could realize the self as agent.

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was broken down.20 Carter et al. (2005) concluded that “These results these negative experiences, as we further discuss in the Discussion.
contrast sharply with the reported observations of over 1000 medi­ To summarize, we discussed key findings in the literature in support
tation-naïve individuals tested previously”. Since it is difficult to main­ of our hypothesis that the temporal thickness of mental activity reduces
tain deep states of meditation while providing responses, participants from FA to OM to ND meditation. These findings also provide initial
were not comfortable in responding during the experiments, and thus evidence for the notion that mental processes of corresponding temporal
the results were dependent on post-hoc self-reports. An important di­ thickness disappear along the way, including eventually basic self-
rection for meditation research is to develop paradigms that do not evidencing.
interrupt the meditation, but can track neural representations and
perceptual experience, which we address further below. The findings by 5.2. Meditation reduces prediction formation and prediction error
Carter et al. also highlight the fact that effects of different meditation signaling
styles can overlap, and that non-dual awareness can also be realized
through FA and OM meditation practices (Wallace, 1999). We will also If experience is more and more reduced to the present moment across
return to this topic in our Discussion. meditation styles, this should also modulate novel prediction formation
Reductions in the temporal depth of processing should also logically and prediction error signaling. Consistent with this idea, Valentine and
lead to changes in the sense of self, as noted above. As meditation Sweet (1999) found that OM meditators were less biased by past tem­
‘prunes the counterfactual tree’ (flattening the predictive hierarchy), it poral regularities than FA meditators. That is, when a stream of auditory
necessarily also prunes one’s sense of self, from a narrative form of tones that participants had to count, suddenly shifted from a slow rate
selfhood all the way to selfless awareness. In line with this, a seminal (0.25hz) to a much faster rate (7hz), the OM group performed better.
neuro-phenomenology study by Dor-Ziderman et al. (2013), 12 experi­ These results may suggest that the OM meditators previously did not
enced vipassana meditators were instructed to enter 3 states of “self-­ develop strong temporal expectations that biased subsequent percep­
awareness”, while MEG recordings were made. The three states—similar tion, in line with the notion that OM induces a state of present-moment
to our characterization—were: the narrative self, the minimal self (or awareness in which experience is less influenced by what just happened
experiencing self), and the “self-less”. Consistent with extensive fMRI or may happen in the future. Another not mutually exclusive explana­
research on self-related processing (Gusnard et al., 2001), attenuation of tion is that, because the unexpected condition was also faster, the OM
the narrative self was supported by decreases in gamma oscillations meditators were better able to ‘release’ each appearing stimulus in order
source localized to frontal and particularly medial prefrontal cortices. to count the subsequent sound (see also Hanley and Garland, 2019 for
Self-less experiences were consistently self-reported to lack agency or evidence that mindfulness training can reduce Pavlovian conditioning).
ownership and emotions (negative, positive, and mixed). Notably, some Whether or not FA meditation reduces novel prediction formation
of the highly experienced meditators who reported the most vividly may depend on whether the inducing stimulus is the object of FA
self-less experiences showed additional attenuation of beta-band activity meditation. Prediction formation may be accelerated when the object of
in the inferior parietal lobule and left dorsomedial thalamus (Dor-Zi­ FA contains predictable sensory variance, given that attention reduces
derman et al., 2013). As noted by Dor-Ziderman et al. (2013), the the relative influence of prior expectations by increasing the gain of
inferior parietal lobule has been implicated as a key region associated sensory prediction errors hence promoting model revision and new
with the sense of agency and subjective control (Nahab et al., 2011). In learning. In line with this, several studies have reported a larger
another study with a similar design, Dor-Ziderman et al. (2016) the mismatch negativity, an event-related potential evoked by an unex­
transition from a minimal form of self-experience to a self-less state in pected stimulus, during FA meditation (Fucci et al., 2018; Srinivasan
ND meditation was associated with changes in beta oscillations localized and Baijal, 2007), indicative of the development of more precise sensory
to the temporo-parietal junction (TPJ, including the inferior parietal expectations through FA. Yet, for events that occur outside of the focus
lobule (as in the previous study) as well as the medial parietal cortex of FA meditation, prediction formation and error signaling should be
including the precuneus (a key node for self-representation). Another reduced, as those are not assigned precision, decreasing prediction
study using functional magnetic resonance imaging (fMRI) in 24 Tibetan formation.
Buddhist meditation practitioners suggests that ND meditation may lead ND meditation has also been associated with reduced prediction
to alterations in interactions between intrinsic networks involved in formation. For example, a study by Antonova et al. (2015) found
self-referential processing, of which the precuneus is a central node, and reduced habituation of the startle response to unexpected, startling
extrinsic networks involved in external, task-related processing (Josi­ sounds. Normally, this phylogenetically primitive defense reflex (Koch,
povic et al., 2011). This finding is consistent with the idea that ND 1999) reduces in strength after repeated presentation of the inducing
practice particularly influences the habitual organization of cognition stimulus. However, this study reported no evidence of startle response
along a subject-object dichotomy. Thus, neuroimaging studies combined habituation in 12 expert meditators who were instructed to rest in a
with phenomenal reports in some cases support radical changes in the non-dual state while being presented with startling sounds. This may
sense of self as a function of meditation. Yet, more work is necessary to suggest that in the ND state, the brain does not develop predictions
directly test our prediction that the sense of self is hierarchically pruned based on new experiences. Interestingly, participants with moderate
away across meditation styles. Also, achieving advanced states of meditation experience showed more habituation than control subjects,
meditation is not a process that is always experienced positively, and highlighting that expertise or depth of meditation may not be a linear
challenging and even impairing experiences can arise (Fingelkurts et al., process, but something more akin to an inverted U-curve (see also
2015; Lindahl, 2017; Lindahl and Britton, 2019). In some cases alter­ Brefczynski-Lewis et al., 2007). Similarly, Levenson et al. (2012) found
ations to the sense of self are also experienced as distressing or resem­ that a highly experienced meditator (40 years of practice) showed a
bling psychopathology (Lindahl and Britton, 2019). Thus, the outcomes smaller startle response when meditating compared to 12 control sub­
of (especially) more intensive meditation may not coincide with the jects, as shown by several physiological markers. Notably, ND medita­
goals of mindfulness practice for many lay practitioners (e.g., reducing tion resulted in the smallest startle response (relative to FA), consistent
stress, being more productive), and more work is necessary to address with our framework. Yet, in another study, the mismatch negativity
generated by an unexpected stimulus was not smaller during ND
meditation compared to a control (reading) condition (Fucci et al.,
20
The Carter et al. (2005) findings also highlight the fact that very advanced 2018). This null finding may suggest that developing predictions based
FA practices may also be able to break down stubborn predictions. Indeed, it is on simple sensory regularities is an automatic process (stubborn), which
believed that some practitioners are able to discover non-dual awareness is corroborated by the fact that the mismatch negativity is still observed
through advanced FA, thus bypassing OM (Wallace, 1999). in comatose patients (Boly et al., 2011). The above studies suggest that

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during more advanced meditative states, the development of new pre­ that would otherwise be out of scientific reach, and their effects on
dictions and prediction error signaling is reduced during some forms of predictive processing. Future studies should also include measurements
meditation, as our model also predicts. They also highlight the potential of physiological activity, such as bodily arousal, that may critically
of meditation to reveal which predictions may be stubborn to change. change during meditation (Britton et al., 2014; Metzinger, 2020).
Yet another major methodological challenge in the scientific study of
5.3. Methodological considerations meditation concerns the fact that participants cannot be blinded to the
nature of the study (i.e., meditation) and hence may have certain ex­
In the above, we discussed main empirical predictions that can be pectations on how meditation should affect e.g., their cognitive perfor­
derived from our model and selectively reviewed key findings from mance that can (implicitly) bias results (i.e., the well-known placebo
meditation studies in light of our many-to-(n)one model. This selective effect; Wampold et al., 2005). A recent study, for example, found that
review also brought up some general challenges inherent to the scientific participants that were recruited using a suggestive flyer, advertising a
study of meditation, that the field of meditation research needs to “brain training and become smarter” study, scored 5–10 IQ points higher
(continue to) address to grow into a mature field of science (Davidson on an intelligence test after performing a 30-min cognitive “training”
and Kaszniak, 2015; Slagter et al., 2011; Van Dam et al., 2018). First, than participants that were recruited using a non-suggestive flyer that
meditation practice is inherently a subjective endeavor, and the number simply advertised a psychological study for monitory reimbursement
of hours of meditation experience does not necessarily indicate how (Foroughi et al., 2016). This example illustrates the profound effects that
advanced someone is in their practice. Thus, developing better methods expectations can have on study outcomes. Participants in a meditation
to determine the quality of meditative states and track meditation study may also be more motivated to do well because they believe
experience is of utmost importance for understanding the physiological meditation has positive effects or because they think the experimenter
and psychological effects of meditation. Neurophenomenology, the expects them to do well. It is therefore critical that meditation re­
combination of brain imaging with micro-phenomenology—detailed searchers try to control for these non-specific effects that can confound
reports about one’s mental experiences—provides one fruitful approach results by including active control groups. Active control groups could
(Petitmengin et al., 2019; Varela, 1996). This could for example clarify if consist of experts in some other domain (e.g., athletes; Andreu et al.,
a practitioner was truly able to induce a ND state in an experimental 2017) that are also invited to participate because of their specific
setup. But much further progress is still possible and necessary. It is expertise, or of participants that undergo a different intervention that is
particularly important that a systematic and validated set of first-person matched to the meditation intervention in the extent to which both the
methods is developed, that is also specifically tailored towards different participants and teachers believe in the effectiveness of the intervention
styles of meditation, but also treats them as lying on a continuum with and on other important variables, such as number of contact hours
partially overlapping effects. While the three styles of meditation are (MacCoon et al., 2014). Yet, an issue here is that it does not make much
here proposed to lie on a continuum, gradually reducing the temporal sense to ask a meditation-naïve person to induce an advanced meditative
depth of processing, their effects also greatly overlap. Present-moment state. One solution is to compare expert to novice meditators. Another
awareness and dereification are for example conceivably higher dur­ possibility is to use meditators as their own controls, for example, by
ing advanced states of FA than during novice OM states (Lutz et al., comparing their brain activity or task performance during different
2015). It is even possible to realize non-dual awareness through FA in states of meditation that are expected to induce differential effects (e.g.,
exceptional cases (Wallace, 1999). This emphasizes the importance of Josipovic et al., 2011; van Vugt and Slagter, 2014). This would not only
being able to quantify and track individual meditation experiences. allow for a better understanding of how different styles of meditation
In developing methods to track stages of meditation advancement, it may differentially affect the predictive brain, and testing of our
is also very important to acknowledge that different meditation tradi­ many-to-(n)one model, but may also better control for potential
tions may have different aims. For instance, classical Buddhism em­ pre-existing differences between expert meditators and controls, e.g., in
phasizes insight into the three characteristics of experience: sleep habits or personality characteristics.
impermanence (aniccā), non-self (anattā), and suffering (dukkha). Thus, Besides proper controls for non-specific effects, it will be important
while we may be able to scientifically determine a meditators capability that the field of meditation research moves in the direction of a-priori
to enter ‘deep states of meditation’ based on our framework, what specification of study predictions and analysis plans through preregis­
exactly constitutes “progress” is also determined uniquely by different tration, to counter experimenter biases during data collection and
meditation traditions and involves factors well beyond the meditation analysis. This is particularly important given that many meditation re­
practice, such as ethical action. In general, researchers should be well searchers are themselves meditators, and believe in the value of
aware of the many different meditation practices and Buddhist tradi­ meditation.
tions that exist, and the historical context in which they developed To summarize, despite much promise of meditation as a powerful
(Dunne, 2015). intervention for neuro-cognitive change, and its potential contributions
Another methodological challenge is that some very advanced to science, progress critically depends on methodological rigor and the
meditative states may make it difficult to provide any useful self-reports development of novel approaches that allow for more objective and/or
whatsoever (during meditation or post-hoc) given the inherently non- non-intrusive assessment of the effects of meditation. Neuro­
conceptual nature of the meditation states. Moreover, one cannot ask phenomenology and no-report paradigms in particular provide fruitful
meditators to engage in typical experimental tasks that require them to avenues for future research. Embracing Open Science is another
respond to stimuli during more advanced meditative states either, as this important step towards scientific progress.
would automatically force them to engage in active inference. Yet, the
consequence of this is that there is very little systematic data about the 6. Discussion
mind during more advanced meditation practices, such as ND. One
promising approach that may reveal the nature and neural basis of “The senses perceive the object, which then the mental consciousness
phenomenal experience during advanced meditative states without instantly conceptualizes in a manner conditioned by all of our past
relying on reports is to combine so-called no-report paradigms with experience, and superimposes this conceptualized version back onto
brain imaging (Tsuchiya et al., 2015). Specifically, machine learning the originally neutral data of our senses—all of this occurring so fast
methods that utilize neural activity as representational information, for that we don’t even notice the process, and are only left in the end
example multivariate pattern analysis or “decoding” techniques—in with the mind’s conceptual version of things that we take to be re­
concert with the delivery of stimuli through so-called no-report para­ ality.” (Thrangu, 2011)
digms—could be used to learn more about advanced states of meditation

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Cognitive neuroscience is undergoing a kind of Gestalt switch, from 6.1. From many to (n)one: Novel insights from a unifying framework
an understanding of the brain as a vessel that ‘drinks in’ the world, to an
organ that repeatedly regurgitates the world through predictions There is a growing body of work investigating how meditation can
derived from the past. This view of experience—as deeply contrived change cognitive, emotional, and neural functioning (Berkovich-Ohana
through past learning—is remarkably similar to Buddhist ideas of the et al., 2013; Dahl et al., 2015; Dor-Ziderman et al., 2013; Fingelkurts
conditioned nature of experience, as the above quote illustrates. More­ et al., 2020; Hölzel et al., 2011; Josipovic, 2014; Raffone et al., 2019;
over, the gradual breaking down of concepts in Buddhist meditation Vago and David, 2012; Vago and Zeidan, 2016). This work has also
maps on strikingly well to the notion of the predictive model-building related specific styles of meditation to changes in predictive processing
brain. (Lutz et al., 2019; Pagnoni, 2019). Here, we extend this work by
Previous research has often focused on how meditation can improve delineating how predictive processing may change from FA to OM to ND
cognitive performance or emotion regulation in one way or another meditation, providing a more unified account of meditation. While our
(Kabat-Zinn, 2003; Lutz et al., 2008; Slagter et al., 2011; Tang et al., many-to-(n)one framework integrates three widely practiced styles of
2015). However, many contemplative traditions from which these meditation, it naturally does not capture the full diversity in meditation
practices emerge suggest that meditation can go much deeper, focusing techniques, particularly more constructive practices such as
instead on understanding one’s “true nature”, “the nature of the self”, or loving-kindness and compassion (Nash et al., 2013).23 Yet, our frame­
attaining certain insights about the nature of reality (Bodhi, 2011a; work could be extended to include other styles of meditation, for
Suzuki, 1961; Wallace, 1999).21 These seemingly esoteric aspects of example, practices that construct mental content and use perspective
meditation have been largely washed out of modern science perhaps for taking and reappraisal as methods to strengthen mental patterns and
easier integration within a secular vision of mind, body, and brain. Yet, conceptions of self that foster well-being (Dahl et al., 2015). It is also
from the perspective of predictive processing, these facets of meditation important to emphasize again that Buddhism is not monolithic. Different
suddenly become less mysterious and instead—we propose—the logical meditation practices were developed at various moments in history
consequence of being truly “at one” with the present moment. That is, within different cultural contexts, and ideas and aims shifted along the
simply being present enough would naturally reduce abstract predictive way (Dunne, 2011). For example, although FA (samatha) is common to
modeling within the brain, and this in turn would naturally give rise to many Buddhist traditions, in non-dual traditions that developed his­
the phenomenology reported at various stages of practice. torically later (e.g., Mahamudra), subject-object orientation is consid­
More specifically, we have put forward the novel hypothesis that the ered problematic and hence the aim became to quickly move beyond
habitual modus operandi of hierarchical predictive processing is pro­ focus on an object and to cultivate non-conceptual sustained attention
gressively broken down by three main styles of meditation (FA, OM, and from the outset (Dunne, 2011; Wallace, 1999). Researchers should be
ND). We postulated that: (1) FA meditation reduces the precision and well aware of the many different meditation practices and Buddhist
frequency of deep temporal models by up-weighting the precision of one traditions that exist, and the historical context in which they developed
input lower in the predictive hierarchy (e.g., the breath). (2) OM (Dunne, 2015).
meditation further reduces counterfactual processing by balancing ex­ In Section 5, we derived several key empirical predictions from our
pected precision, thus permitting non-judgmental experiencing. Finally, novel framework and reviewed existing scientific evidence in their
(3) ND meditation creates the conditions for the final subject-object support. Here we outline the larger scientific value of our framework,
abstraction to fall away. In the ND state, all expected22 error- with implications to our understanding of mental plasticity, psychopa­
minimization and thereby conceptualization (including self and time) thology, and self. We then discuss how our many-to-(n)one framework
ceases. may specifically help address several main outstanding questions within
We also proposed in Section 4 (see also Fig. 2) that FA, OM, and ND contemplative science, including how meditation practice may induce
may gradually abate the construction of self-processing at different enduring or trait changes in brain and mental functioning, how to
levels of the predictive hierarchy, from the narrative self (i.e., thinking), determine meditation expertise, and how to approach negative
to the embodied experiencing self (i.e., sensing), to non-self (i.e., meditation-related experiences.
awareness). We also showed how key insights—as targeted in classical
Buddhism—can occur through meditation (Section 3.2). We proposed
that reducing abstract processing in the predictive hierarchy may reveal
certain insights about one’s mind by increasing the transparency of
predictive processes (e.g., discovering the impermanent or ‘conditioned’
23
nature of one’s predictions as they are constructed and deconstructed). We certainly do not seek to devalue constructive practice, and in many
Further insights may arise through fact free learning (Friston et al., traditions, they play a most central role (e.g., Vajrayana Buddhism). It is pri­
2017)—the internal revision and refinement of models supported by the marily for the sake of scope that we have omitted a discussion of constructive
meditation practices, however, by simply reversing the causal arrow within our
holistic non-action of meditation (i.e., in-active inference, Section 2.5).
model (from deconstruction of the predictive hierarchy to reconstruction), one
Below, we first discuss the scientific value of understanding meditation
can see how these practices could fit naturally within our framework in a
as pruning the counterfactual tree and outline important avenues for complementary fashion to deconstructive meditation.
future research. We then review how our framework may also help 24
As soon as one is ‘away’ from the present moment, one has made an
address current challenges within the field of contemplative science ‘abstraction’. For example, there are the wavelengths of light that represent the
specifically. shape of a ‘teacup’. However, once it has been conceptualized as a teacup there
is a new level of abstraction that demands further inference from past experi­
ence than simply representing the wavelengths of light (i.e., more temporally
deep processing). And yet, experiencing a ‘tea cup’ first necessitates the rep­
21
As noted by Britton et al. (2014): “In his Science and Buddhism: A Guide for resentation of the wavelengths of light contacting the retina (thus, hierarchical
the Perplexed, Buddhist studies scholar Donald Lopez [(Lopez, 2009)] laments processing). Representing the teacup then permits further hierarchically deep
“Where is the insistence that meditation is not intended to induce relaxation but processing: Such as recalling the time you drank green tea with brown rice
rather a vital transformation of one’s vision of reality?” Others warn how “a kernels in a Japanese garden.
25
practice that only relaxes the mind might eventually prove harmful.” [(Lutz In Fig. 3 we have used different levels of the hierarchy than Fig. 2 in order
et al., 2006)]” to emphasize the behaviour of generative models. In lower levels in the hier­
22
As discussed in section 2.4 & 4, expected free-energy minimization involves archy (i.e., “pure witnessing” or the subject/object divide shown in Fig. 2) there
predictions about states in the next moment (thus, counter-facts to the present is no longer phenomenology of sensory objects, and if there are, they are arising
moment, Friston, 2018). in later levels.

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6.1.1. The scientific value of meditation states of selfless awareness. It can also well explain the alleged clinical
Meditation, as conceptualized as deconditioning the predictive effects of meditation-based interventions.
mind, may provide a unique method to scientifically investigate the
plasticity and automaticity of predictive processing by revealing what is 6.1.2. Insights for contemplative science
amenable to change from within, and what is not. Yon et al. (2019) Next to its scientific value, our many-to-(n)one framework may
recently coined the term ‘stubborn’ prediction, to emphasize that some specifically help address several main outstanding questions within
predictions may be so deeply engrained in the structure of our minds contemplative science, including how meditation practice may induce
that they are not amenable to change. They for example suggested that enduring or trait changes in brain and mental functioning, how to
the sense of agency is a stubborn prediction, but as now suggested by determine meditation expertise, and how to approach negative
multiple studies, the sense of agency can fall away during meditation meditation-related experiences.
(Dor-Ziderman et al., 2013, 2016; Fingelkurts et al., 2020; Lindahl and As state-level meditation changes are known to lead to longer-term
Britton, 2019; Metzinger, 2020). Thus, meditation studies may reveal trait-level changes (Cahn and Polich, 2006), one may also expect that
what predictions are evolutionary or phylogenetically constrained in meditators should display differential functioning of the predictive
human beings, and what structures of experience are amendable to processing machinery ‘off the cushion’. Drawing on our framework, and
change. earlier suggestions (Pagnoni, 2019), we propose that meditation may
Our framework may be particularly useful for gaining an under­ increase the counterfactual richness of processing outside of formal
standing of the plasticity of mental processes at levels of the hierarchy meditation by weakening ingrained prediction loops during meditation.
that are detached from the current environment, and involved in The broadscale loosening of beliefs may permit more flexibile and
counterfactual cognition. Building on the notion put forward within multidimensional processing (a prospect there is already some evidence
predictive processing that our inner mental landscape too is dominated for, Moore and Malinowski, 2009). More advanced meditators may also
by generative models that through past experience have come to reliably be expected to naturally reside in a state where, over time, there is less
minimize uncertainty, we propose that by assigning less precision to abstract counterfactual cognition. This does not mean that a meditator is
predictions that normally habitually arise in experience, meditation may incapable of abstract processing, but that the habitual tendency to
in the long term ‘decondition’ the mind. This may have beneficial ef­ engage with deep temporal models ought to decrease, and be more
fects, for example reducing excessive rumination. Although rumination easily attenuated. Indeed, there is fMRI evidence that meditators
can have adaptive value when it is not excessive (Baird et al., 2012; Vago (regardless of tradition) may “…transform the resting state into one that
and Zeidan, 2016), pruning these high-level counterfactual cognitions resembles a meditative state” (Brewer et al., 2011, p. 20,255; see also
through meditation may be one way to revise the immense multiplicity Fingelkurts et al., 2016). Some well-known adepts of non-dual medita­
of thoughts to those that are adaptive to one’s goals. Counterfactual tion have even claimed that perceptions, sensations, and hence ‘the
pruning may also explain the clinical effects of mindfulness-based in­ world’ does not exist for them, because the appearance of sensing and
terventions in treating depression, anxiety, stress, and more (Chiesa and high-level thinking may be highly infrequent or barely noticeable
Serretti, 2009; Hofmann et al., 2010) although more work is still (Maharshi, 2004; Nisargadatta, 1973). Long-term practice may hence
necessary (Van Dam et al., 2018). Such clinical outcomes may also reduce the frequency of arising predictions in experience and their
conceivably follow from an initial deconstruction of problematic habits expected precision over time. In general, meditators should experience
of prediction, and then a ‘healthier’ reemergence. This healthier less habitual grasping onto passing experience i.e., they should display a
reconstruction may be achieved particularly through model selection, decrease of salience and stickiness of arising predictions (see for
optimization, and compression mechanisms (described in Section 2.5) or example, van Leeuwen et al., 2009). Thoughts and feelings may also
through active reconstruction of alternative modes of thinking and become less self-related, which may foster an enduring sense of psy­
feeling. Many meditation traditions also include ‘constructive’ practices chological well-being (Dambrun and Ricard, 2011).
that for example target maladaptive self conceptions and replace them Our many-to-(n)one model can also mechanistically explain the
with more adaptive conceptions of self (Dahl et al., 2015). These prac­ occurrence of insights in meditation, and how these may penetrate
tices likely provide important ingredients for guiding ‘change’ in a subsequent experience (which has not been addressed by any theory of
positive direction. meditation to our knowledge). In our model, meditation-induced in­
Our framework also generates testable predictions about the plas­ sights simply reflect another way in which the brain revises its predictive
ticity of self or how meditation may gradually break down the self across models, through Bayesian model reduction through fact free learning.
the predictive processing hierarchy. So far, science has gained most of its Fact free learning allows the brain to construct new, simpler models with
insights about the constructed nature of self-processing through clinical greater explanatory power (Friston et al., 2017), which may drive the
populations, such as depersonalization disorder and schizophrenia, that transition of meditation from state to trait. Meditation is a unique
display alterations in the sense of self that are highly debilitating and practice in the sense that it reduces typical active inference processes
accompanied by several comorbidities and other symptoms. The scien­ (including mental actions) and may thereby accelerate the revision or
tific study of ND meditation in particular may be crucial for better un­ refinement of existing models.
derstanding the nature and neural basis of the so-called minimal Our model also has implications for what might constitute markers of
phenomenal experience, consciousness without self-location in space, meditation expertise. Currently, expertise in meditation is notoriously
time representation or self-consciousness (or ‘sciousness as William difficult to pin down and there has been much inconsistency on what
James termed it) (Metzinger, 2020). This state of awareness is currently counts as an experienced meditator in the literature (Van Dam et al.,
not included in any major cognitive neuroscience theory of conscious­ 2018). According to our account, meditative expertise could be partly
ness, yet, proposed by some to lie at the core of all conscious experi­ captured by the extent to which the meditator is able to voluntarily
encing, as discussed above. Some expert ND meditators can allegedly modulate objective markers of stubborn predictions. For example,
reliably induce the non-dual state in laboratory settings, rendering this Antonova et al. (2015) found that startle habituation discriminated in­
basic self-less awareness accessible to scientific investigation. Yet, as tensity of meditation practice better than self-report, dispositional, and
elaborated on in Section 5.3, this will require the development of novel practice-related measures. Thus, they proposed that habituation to the
methodological approaches, that include neurophenomenology and startle response could be used as an objective marker of expertise. We
no-report paradigms. suggest that the startle response represents one of many possible
To summarize, approaching meditation as a method to deconstruct objective markers of meditation expertise because it is a highly auto­
hierarchical predictive processing can provide unique insights into the matic response (i.e., a stubborn prediction). Many other measures could
plasticity of the predictive mind, the construction of experiences, and foreseeably be used, ideally in combination, to test whether a

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practitioner is able to enter states that are free from such habitual re­ able to experience oneself outside of the meditation context as a boun­
sponses. Crucially, the more automatic the prediction, the more exper­ ded individual that unifies experience from within, across time, and that
tise would be required to prevent the habitual response. is capable of exerting effects on the world, to function in this world.
To provide a few new directions for research on meditative depth, we Changes to the narrative self often occurred even during daily practice
suggest the following automatic responses are worthwhile investigating (33 %), whereas the vast majority of more profound changes to one’s
further, (1) implicit learning, statistical learning, and conditioning, (2) basic embodied self happened while on a meditation retreat (93 %).
conceptual processing, such as the automatic formation of words from Under an ‘emotion and attention regulation’ view of meditation, such
sounds, (3) visual illusions, such as perception of illusory shapes, and (4) experiences seem surprising. However, within our framework, a
the volitional modulation of wakefulness and arousal (Britton et al., deconstruction of self-related processing naturally arises from being
2014). Intriguingly, since many decisions and tasks require abstract, immersed in the here and now, and changes to more basal forms of
self, time, and space related processing, it is also possible that perfor­ self-hood are expected with more prolonged and advanced practices,
mance on some tasks would be impaired due to meditation. For example, like those employed on meditation retreats. Thus, our framework is able
while some mindfulness-based interventions might improve learning by to also account for the negative side effects of meditation, especially as
enhancing the ability to focus attention (Laukkonen et al., 2020b), other they pertain to changes in self-related processing.
meditation practices may reduce the ability to learn and retain new The prospect of severe negative side effects that outlast the actual
information or extract statistical regularities. Indeed, a study in meditation, including depersonalization and dissociation (Lindahl and
non-meditators showed that individuals scoring high on self-reported Britton, 2019) certainly demands further research. One possibility
mindfulness displayed impaired artificial grammar learning (Whit­ drawn from our framework is that if during meditation one’s sense of
marsh et al., 2013). Thus, just as meditation may not always improve self does not fully abate, but instead is partially altered, this may then be
performance, it may not always lead to positive experiences. Impair­ experienced as distressing. Many aberrant experiences of self that may
ments in predictive learning based on regularities in the environment occur during for instance psychosis and schizophrenia, may indeed
could thus provide a useful marker of meditative depth. represent changes to self-modeling processes rather than the explicit
It is also possible for future experiments to directly test the contin­ absence that may arise through carefully guided and personalized (Fin­
uum of deconstruction that we proposed, wherein FA, OM, and ND gelkurts et al., 2015, 2020) meditation training. Similarly, as counter­
gradually reduce predictive processing at deeper levels (see Figs. 2 and factual processing is deconstructed and early levels of the predictive
3). For example, linguistic processing requires multiple levels of inte­ hierarchy become perceptible, what is discovered may not coincide
gration at different temporal scales and levels of abstraction (indeed strongly contradict) one’s models at higher more abstract levels
(Bekinschtein et al., 2009; Dehaene et al., 2015; Ding et al., 2017; Gilead of the hierarchy, which may cause uncertainty and distress, particularly
et al., 2019; Henin et al., 2019). Thus, we would expect that relative to a if these changes persist outside of the meditation session. Meditation
non-meditative state, FA reduces markers of higher order processing and thus may engender enormous prediction errors that can demand sig­
conceptualization (e.g. later components in the ERP) but possibly in­ nificant support and integration. As the popularity of meditation grows,
creases processing at early stages (e.g., earlier components in the ERP). more attention is needed within the secular meditation movement about
This pattern of decreased later ERP components and therefore dimin­ the side-effects that practitioners may unwillingly encounter, and what
ished higher order processing would be expected to increase with ‘priors’ may be necessary to integrate surprising experiences in a healthy
meditative depth. Thus, in response to linguistic stimuli, OM ought to way. We stress that being present is not just an easy way to feel better
lead to decreased differentiation in later components than FA, and ND but can in fact profoundly change how we view ourselves.
the least of all. Besides ERPs, multivariate methods such as decoding
could also be used to disentangle early versus late conceptualization 6.2. Conclusion
(Grootswagers et al., 2017). For example, as with the ERPs described
above, we would expect decoding of linguistic representations from We have taken on the daunting task of providing a theory for un­
neural activity to become increasingly ‘short’ and show less temporal derstanding the effects of meditation within the predictive processing
generalization as meditative depth increases from FA to ND. The above, framework. Contemplative science is a young field and predictive pro­
in concert with markers of hierarchical prediction-error processing cessing is a new theory, although both have roots going much farther
(Wacongne et al., 2011), and learning statistical regularities over time back. All theories are subject to change, but perhaps particularly so for
(Dehaene et al., 2015), provide concrete ways to test the continuum of such new domains of enquiry. Nevertheless, we think the conditions are
deconstruction proposed in the many-to-(n)one model. Of utmost suitable for a more overarching theory that may also thwart further
importance for such studies is carefully identifying expertise (e.g., using siloing and fragmentation of scientific research, as has been common­
multi-pronged methods) and tracking trial-by-trial phenomenology (e. place among the mind-sciences. A strength of our framework is its
g., using experience sampling) so that state meditative depth can be simplicity: Being in the here and now reduces predictive processing. And
measured with fidelity. yet, this basic idea can explain how each meditation technique uniquely
Finally, within our framework, which considers the self an inferred deconstructs the minds tendency to project the past onto the present,
model that is hierarchically deconstructed by meditation, negative how certain insights may arise, the nature of hierarchical self-
meditation-induced changes in the sense of self can also be understood processing, and the plasticity of the human mind. There is scope here,
in a novel way. As already briefly mentioned, meditation-induced we think, to eventually reveal what makes a meditator an expert, why
changes in self are not always positive, and can in fact be debilitating meditation has such broad clinical effects, and how we might begin
in daily life when they persist (Britton, 2019; Lindahl et al., 2017; Lin­ mitigating some of the negative consequences of meditation. Last but
dahl and Britton, 2019). Of particular relevance is a study conducted by not least, our framework seems to bring ancient Eastern and modern
Lindahl and Britton (2019) on changes to sense of self. They found that scientific ideas closer together, showing how the notion of conditioned
72 % of meditators—many of which were meditation teach­ experience in Buddhism aligns with the notion of the experience-
ers—reported experiencing changes to their sense of self as a conse­ dependent predictive brain.
quence of practice, and 55 % of these were accompanied by distress, and
45 % with impairments in functioning. Changes to sense of self included Acknowledgements
changes to the narrative self, loss of ownership, loss of agency, changes
to embodiment, changes to self-other or self-world boundaries, and the This work was supported by an ERC starting grant (679399) to H.A.S.
most debilitating experiences tended to accompany a loss of one’s ‘basic’ We would like to thank several colleagues and meditation teachers who
self or sense of ‘being’. These findings emphasize the necessity of being provided insightful comments on our paper, including Henk Barendregt,

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