The body in the extra-personal space
Perception is for action
Chiara Fini
The body in the extra-personal space
The space categorization
The body in the extra-personal space
Should I
stay or
Should I go?
• Body
• Motor Potential
• Intention
The body in the extra-personal space
• The unites used to scale the space are action specific
• The motor potential and the action intention affect the space categorization
Proffitt et al., 2003; Witt et al., 2004; Sugovic et al., 2013; Schnall et al.,2013
The body in the extra-personal space
Studies Overview:
Which processes drive our space representation when considering another acting body?
• How the presence of another person affects the Extrapersonal space categorization
• How we categorize the Extrapersonal Space when the other person is adopted as allocentric reference frame
• How the observation of biological movement impacts the Extrapersonal space categorization
• The role of belief about the animacy of the reference frame in the Extrapersonal space categorization
• A tDCS study about the Extrapersonal Space categorization
The body in the extra-personal space
• How the presence of another person affects the Extrapersonal space categorization
TASK: dicotomic categorizarion “ Near”/“Far” of a target distance respect with
different reference frames
Limit Method: measures the perceptual threshold in which stimuli with increasing
or decresing intensity are presented until the subject changes the perceptual
judgment
JUDGMENT TRANSITION’S THRESHOLD (JTT)
Study 1
• How the presence of another person affects the Extrapersonal space categorization
Egocentric Egocentric with Other Egocentric with Object
NES (m)
Ego Ego (Other) Ego (Object) Fini, Costantini & Committeri, 2015 Plos One
F(2,28)=14.89, p<0.001
Study 1
NES (m) F=(2,46)=3,64, p<0.03
Ego(Dummy) Ego (Other) Ego (Object) Fini, Costantini & Committeri, 2015 Plos One
Study 1
• A human body located in the scene impacts on the space categorization
• According with the data on the peripersonal space, the presence of another
agent modulates the distance perception (Costantini et al., 2011; Bloesch et
al., 2012)
• A body affects the space perception when is real and when is fake:
not fine-grained processing during the egocentric distance judgment
• A human shape would be represented as a competitor, the reduced distance
would have the evolutionary meaning to provide an advantage in the
behavior to be performed in order to reach the target.
Study 2
• How we categorize the Extrapersonal Space when the other person is adopted as allocentric reference frame
Ego RF Object RF
Other RF Dummy RF
Fini, Brass, Committeri 2016, Cognition
Study 2
F(2,44)=72.4, p<0.001 F(2,32)=9,88, p<0.001
F(2,58)=2,81, p<0.5 Fini, Brass, Committeri 2016, Cognition
Study 2
• Motion potentialities attributed to the allocentric reference frame determine the reduction
of perceived distance
• Compared to the egocentric judgment, in the allocentric judgment the
processing of the human body is more fine-grained
• In line with Committeri et al., 2004; Galati et al., 2010 it would be an involvement of the
visual ventral stream during the allocentric more than during the egocentric judgment.
Study 3
• How the observation of biological movement impacts the Extrapersonal space categorization
F(1,29)= 7,23,p < 0.03
Fini, Bardi, Troje, Committeri & Brass, 2016, Acta Psychologica
Study 3
Study 3
F (2.40)= 4.79, p<0.03
Fini, Bardi, Troje, Committeri & Brass, 2016, Acta Psychologica
Study 3
Fini, Bardi, Troje, Committeri & Brass, 2016, Acta Psychologica
Study 3
F(1,31)= 7,82, p<0.0
Fini, Bardi, Troje, Committeri & Brass, 2016, Acta Psychologica
Study 3
• Subjective social scaling of extrapersonal space is related not only to the RF’s motion potential, but also to the actual
activation of a specific movement pattern.
• The motion type affects the subjective social scaling of extrapersonal : the more the action is efficient to cover the
distance, the more the distance is categorized as reduced.
• The general motion potential of a human body is not a sufficient condition to filter extrapersonal distance, but a
critical role is also played by the attribution of a motor intention and of a coherent pattern of movement associated
with it
Study 4
• The role of belief about the animacy of the reference frame in the Extrapersonal space categorization
Other Dummy
Fini, Committeri, Müller, Deschrijver & Brass 2016, Plos One
Study 4
Trasportantion score
r = -.32 p = .009
NESB-NB
The more people identify themselves with this character, the more they consider the
wooden dummy as an intentional agent, so endowed with a potential biological motion
that filters the space perception.
This phenomena is called ANTHROPOMORPHISM (Epley et al., 2008)
Fini, Committeri, Müller, Deschrijver & Brass 2016, Plos One
Study 5
• A tDCS study about the Extrapersonal Space categorization
INFERIOR FRONTAL GYRUS
Fini, Bardi, Epifanio, Committeri, Moors & Brass, 2016, Exp Brain Research
Study 5
F(2,52) = 3.5, p < .05
Fini, Bardi, Epifanio, Committeri, Moors & Brass, 2016, Exp Brain Research
The body in the extra-personal space
F(2,50) = 5.75, p < .001
Fini, Bardi, Epifanio,Committeri, Moors & Brass, 2016, Exp Brain Research
Study 5
• IFC is recruited during the extrapersonal space categorization task
• the underlying mechanisms behind the reduced perceived distance could be the
semantic attribution of the biological nature to a human, an automatic visual–spatial
perspective taking and consequently the promotion of the interpersonal motor
resonance
• these processes are modulated by the individual level of cognitive perspective taking,
with a weak level allowing responsivity to IFC activity boosting
The body in the extra-personal space
General Conclusions:
The body in the extra-personal space
General Conclusions:
The body in the extra-personal space
General Conclusions:
NES
Peripersonal
Motor simulation space
The body in the extra-personal space
General Conclusions:
NES
Peripersonal
Motor simulation space
Prof Giorgia Committeri ITAB Chieti, Italy
Thanks for the attention
Prof Agnes Moors KU Leuven, Belgium Lara Bardi UGent, Belgium
Prof Marcel Brass Ugent, Belgium
