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◇What is perceptual organization?

Perceptual organization refers to the way information is received by our
senses and interpreted to make it meaningful.
According to Roediger, “ The structuring of elementary sensations such
as points, lines and edges into the objects we perceive is called
perceptual organization.”
According to Robert A Baron, “The process by which we structure the
input from our sensory receptors is called perceptual organization.”
Perceptual organization is a process that groups the visual elements so
that it is easy to determine the meaning of the visual as a whole. It is an
essential concept because it allows individuals to make sense of the
things that they see at a rapid pace. The perceptual organization also
helps to lead the viewer to the appropriate conclusion that suits our
purpose.
The perceptual organization theory has been aptly explained by Gestalt
psychologists who believed that the human brain is capable of creating a
conscious perceptual experience by observing the stimulus as a whole
and not as the total of its parts.
There are two factors of perceptual organization.
a) Stimulus factors
b) Organismic factors

◇Organismic factors of perceptual organizations

Biological factors originate from the individual and help in the
organization of perception. Biological components are discussed below.
1. Needs and Perception:
Physical and emotional needs have an effect on perception. Needs like
hunger, thirst, lust etc. affect the perception of a person. Levine, Chein
and Murphy (1942) conducted an experiment with a group of college
students. In this experiment, subjects were shown a series of ambiguous
pictures 1 hour, 3 hours, and 9 hours after consuming food. Test
subjects who abstained from food for 3 hours and 6 hours perceived
them as food items.
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2. Emotions:
Emotions affect a person's perception. Driven by emotions, people fail to
perceive an object or event as it really is. Emotional people cannot
perceive an object or event with an unbiased perspective.
3. Preparation and Expectation:
While witnessing an object or event, we prepare mentally. Such
preparation has a considerable effect on perception.
“How preparation and anticipation influence perception is well illustrated
in an experiment by Sipler (1935). He showed a series of ambiguous
words to two groups of subjects very fast through tachytoscope. He
instructed one group to look for words with animal names and another to
look for words related to travel.
The results showed that those who were told to see animal-related
words were more likely to recognize the names of birds. On the other
hand, those who were told to look for words related to travel they did so.
So it appears that cues and expectations influence our world of
perception.
4. Values and Perception:
Values and Perception of an individual help in organization. Not
everyone has the same values on every subject.
Postman, Bruner, and McGinnis (1948) used a number of words
presented to participants at a rapid rate to assess value. The results
showed that the subjects were able to identify the words related to their
values very easily. For example, people with religious values can easily
recognize religious words.
5. Learning and Perception:
Learning affects perception. In the experiment of Synder and Pronko
(1952), they tasked the subjects with selecting a number of satisfied
cards and arranging them into two boxes. In this work, the experimenters
used reversed glasses. As a result, their efficiency decreased. But after
using the opposite glasses for a few days, they were able to pick cards
again at a faster speed. Thus, it appears that learning occurs from the
practice of a task, and such learning results in changes in perception.
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6. Attitude and Perception:

A person's attitude is formed from the possibility of favorable and
unfavorable reactions to an object or product. It helps to identify such
attitude of the person; For example, sports news will be more important
to an activist among various news items in the newspaper.
7. Interests and Perception:
It is normal for us to have an interest in a person, object or product. Such
interest helps in anticipatory organization; For example, even if there are
hundreds of stores in a shopping center, If the consumer is interested in
buying books, he will visit various libraries and find the required books.
So perception is influenced by individual's interests.
8. Fatigue and Perception:
Fatigue affects perception. A tired and sick person cannot concentrate
on any object or event. An interesting object is also identified as a boring
object due to fatigue, and when the fatigue is removed, the object is not
perceived as boring.

◇ Selectivity in attention
“Selective attention refers to the processes that allow an individual to
select and focus on particular input for further processing while
simultaneously suppressing irrelevant or distracting information.”
People are continuously inundated with endless amounts of information.
External stimulation, internal thoughts, emotions, and other forces all
compete for our attention. To deal with this, people utilize selective
attention to tune out things they don’t need to focus on and concentrate
on the important things. In this process, people focus awareness on only
a narrow part of visual information. It works much like a highlighter or
spotlight to make the information you need to attend to more visible and
attention-getting, while you can tune out other, less relevant information.

Selectively focusing on certain information makes it easier for people to

process and encode that information and has been linked to better
memory performance.
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Selective attention is the process of focusing on a particular object in the

environment for a certain period of time.
Visual Attention
Visual attention is often described in one of two ways. First, is the
spotlight model, which suggests that selective attention to visual
information works like a spotlight. You focus on what is lit up by this
“spotlight.” While you can still see the information outside the focal point,
it is less clear.
Auditory Attention
Selective listening is one example of how selective attention allows
people to focus on specific information inputs. In selective listening,
people listen to only a small portion of a given sound or conversation.
For example, you might selectively listen to a podcast while tuning out
background chatter and noise.

◇Why is perception important in psychology?

Perception is crucial in psychology because it forms the basis of how we
interpret and make sense of the world around us. It involves the process
of organizing, interpreting, and giving meaning to sensory information
received from our environment. Understanding perception helps
psychologists study how individuals gather and process information,
which in turn influences their thoughts, emotions, and behavior.
Perception is essential in psychology for several reasons:
1. Interpreting Reality:
Perception shapes our understanding of reality. It's not just about seeing
things as they are, but as we perceive them to be. This subjective
interpretation influences our beliefs, attitudes, and actions.
2. Cognitive Processes:
It's a cornerstone of cognitive processes like attention, memory, and
learning. How we perceive information affects what we attend to, what
we remember, and how we learn new things.
3. Sensory Integration:
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Perception involves integrating information from various sensory

modalities (sight, sound, touch, etc.). This allows us to form a cohesive
understanding of our environment.
4. Adaptation and Survival:
Perception is crucial for survival. It helps us quickly identify potential
threats and adapt to changing environments.
5. Social Interaction:
It plays a fundamental role in social interactions. How we perceive others
and how we believe others perceive us influences our social behavior,
including communication, empathy, and cooperation.
6. Development and Aging:
Perception changes over the lifespan. Studying how perception
develops in children and how it changes in older adults provides
valuable insights into cognitive development and aging.
7. Neuroscience and Brain Function:
Perception is closely tied to brain function. Research in neuroscience
often focuses on how different areas of the brain process and integrate
sensory information.
In summary, perception is a foundational concept in psychology that
influences our cognition, behavior, and overall experience of the world.
It's a multidisciplinary topic with wide-ranging applications in various
fields of psychology and beyond.

◇ Discuss neural communication?

Neural communication is the process by which nerve cells, or neurons,
transmit information within the nervous system. The basic properties of
neural communication include:
Electrical Signaling: Neurons generate electrical signals called action
potentials. These signals allow for rapid and long-distance
communication within the nervous system.
Chemical Signaling: Neurons communicate with one another and with
other cells (such as muscle cells or gland cells) through chemical
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neurotransmitters. These neurotransmitters are released at synapses,

the junctions between neurons.
Resting Membrane Potential: Neurons maintain a resting membrane
potential, an electrical charge difference across their cell membranes.
This potential is essential for the generation of action potentials.
Action Potentials: Action potentials are rapid changes in membrane
potential that allow for the transmission of information along the length of
a neuron. They follow the all-or-nothing principle, meaning they either
occur fully or not at all.
Synapses: Neurons transmit signals to each other at synapses.
Presynaptic neurons release neurotransmitters into the synaptic cleft,
where they bind to receptors on the postsynaptic neuron, initiating a
response.
Neurotransmitter Reuptake: After neurotransmitters have transmitted
their signals, they are often taken back up into the presynaptic neuron in
a process called reuptake, terminating the signal transmission
Excitatory and Inhibitory Signals: Neurons can transmit excitatory signals
that depolarize the postsynaptic membrane (making it more likely to fire
an action potential) or inhibitory signals that hyperpolarize the membrane
(making it less likely to fire).
Integration of Signals: Neurons integrate the signals they receive from
multiple synapses before deciding whether to generate an action
potential. This process occurs in the axon hillock.
Saltatory Conduction: In myelinated neurons, action potentials "jump"
between nodes of Ranvier, speeding up signal transmission along the
axon.
These basic properties of neural communication are fundamental to how
the nervous system processes and transmits information, allowing us to
perceive, think, and respond to our environment.

◇ Transformation of Light into Electricity

Vision begins in the eyes. The light of an object is reflected from nature
and enters our eyes through the pupil. It then concentrates on the
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cornea and lens and travels to the retina to form an image. Retina is the
area of light perception. There are two photosensitive cells called rods
and cones located in the retina. Both of these receptor cells contain
light-sensitive substances called pigments that convert light into
electrical signals. This signal is then integrated into the brain via the
optic nerve in the eye. The cornea and lens are located at the front of
the eye. Nerves and receptors send signals to the retina and then to the
brain, so we perceive objects.

The process of transforming light into an electrical signal in our eye

involves several key steps:

1. Light Entry: Light enters the eye through the cornea, the
transparent outermost layer of the eye. The amount of light
entering the eye is regulated by the pupil, which can expand or
contract. The iris, the colored part of the eye, controls the size of
the pupil. The light then passes through the lens, which focuses it
onto the retina. The lens changes its shape to adjust focus.

2. Convergence & Accommodation: Once light enters the eye from

an object, it is focused on the retina. Cornea Here the light is 80%
concentration function. Next is the lens. Lenses work like glasses.
The lens focuses 20% of the light. The lens adjusts the size of the
object and objects at different distances. Even if a person sees a
small object that is far away, the lens adjusts and focuses it.

3. Light absorption: The retina is a layer of light-sensitive cells at

the back of the eye. It absorbs the light and processes reflection.
Retina contains two types of photoreceptor cells - rods and cones.

— Cones are responsible for color vision and are concentrated

in the central part of the retina.
— Rods are more sensitive to low light and are found in greater
numbers towards the periphery.
When light hits these photoreceptor cells, a molecule called retinal within
them changes shape, which triggers a series of chemical reactions.
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4. Electrical Signal Generation: These chemical reactions create

an electrical signal. The signal is then transmitted through bipolar
cells and ganglion cells, which process and transmit the
information to the optic nerve. The optic nerve carries these
electrical signals in the form of action potentials to the brain. In the
brain, the electrical signals are further processed and integrated in
the visual cortex, where they are interpreted as the images we
perceive.

This process is known as phototransduction, and it's essential for our

sense of vision.

◇ What is basic color? Opponent process theory

“Primary colors are basic colors that can be mixed together to produce
other colors. They are usually considered to be red, yellow, blue.”
Primary colors are perceived based on the light that is reflected and
seen by the eyes. They are considered unique and singular.
Three spectral colors can be mixed to match any other color,
including white light but excluding black.
It’s also called: subtractive primary any one of the spectral
colors cyan, magenta, or yellow that can be subtracted from white light
to match any other color. An equal mixture of the three produces a
black pigment
All other colors look like a mixture of two or more of these colors and
they play a unique role in the processing of color by the visual system.

“The opponent process is a color theory that states that the

human visual system interprets information about color by
processing signals from photoreceptor cells in an antagonistic
manner.”
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The theory was first proposed in 1892 by the German physiologist Ewald
Hering, who noted that there are some color combinations that people
never see.

According to the opponent process theory, the mind can only register the
presence of one color of a pair at a time because the two colors oppose
one another.

Features:

1. In the theory, there are three independent receptor types which all
have opposing pairs:

 white and black,

 Blue and yellow,
 red and green.

2. according to this theory, for each of these three pairs, three types
of chemicals in the retina exist, in which two types of chemical
reactions can occur. These reactions would yield one member of
the pair in their building up phase, or anabolic process, whereas
they would yield the other member while in a destructive phase, or
a catabolic process.
3. The opponent color process works through a process of excitatory
and inhibitory responses, with the two components of each
mechanism opposing each other. For example, red creates a
positive (or excitatory) response in a cell, while green creates a
negative (or inhibitory) response.

The opponent process theory covers the following aspects of color

vision:

a) Positive afterimage:

The positive after-image occurs after we stare at a brightly illuminated

image on a regularly lighted surface and the image varies with increases
and decreases in the light intensity of the background.

b) Negative afterimage:

This theory also explains negative afterimages; once a stimulus of a

certain color is presented, the opponent color is perceived after the
stimulus is removed because the anabolic and catabolic processes are
reversed.
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c) Color blindness:

Color blindness is due to the lack of a particular chemical in the

eye.

For example: In case of red-green color blindness, it is

considered that the photochemical substances sensitive to red-
green colors have been destroyed. Again, if blue-green color
blindness, the photochemical substances sensitive to blue-
green color are considered to have been destroyed.

Criticism:

1) Incomplete Explanation of Color Blindness: According to this theory,

the color blindness in green color and red color should appear at the
same time. Because, the senses of both colors are organized by the
same substance. So the explanation about color blindness is not
adequate.

2) Incomplete Explanation of Color Sensation: Assimilation or Anabolism

and Dissimilation or Catabolism have been mentioned as the main
causes of color sensation. Many consider this explanation of color
perception to be incomplete.

3) Lack of acceptance of basic colors: According to this theory, the basic

colors are red, green, blue and yellow. But why they are basic is not
shown. So there is a lack of acceptability in basic characters.

◇ The structure and function of brain

The most important and complex part of the CNS is the Brain, enclosed
within the skull.
On average, an adult brain weighs between 1.0 kg – 1.5 kg. It is mainly
composed of neurons – the fundamental unit of the brain and nervous
system. Recent estimates have suggested that the brain contains
anywhere between 86 billion to 100 billion neurons.
The human brain controls nearly every aspect of the human body
ranging from physiological functions to cognitive abilities.
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Parts of Human Brain

Following are the major parts of the human brain:

1. Forebrain – Largest part of the brain

It is the anterior part of the brain. The forebrain parts include:

 Cerebrum
 Hypothalamus
 Thalamus.

2. Midbrain: Smallest and central part of the brain

consists of:

 Tectum
 Tegmentum

3. Hindbrain: The lower part of the brain

Composed of:

 Cerebellum
 Medulla
 Pons
A. Forebrain:

♧ Cerebrum
The cerebrum is the largest part of the brain. It consists of the cerebral
cortex and other subcortical structures. It is composed of two cerebral
hemispheres that are joined together by heavy, dense bands of
fibre called the corpus callosum. The cerebrum is further divided into
four lobes:

– Frontal lobe: It is associated with parts of speech, planning,

reasoning, problem-solving and movements.
– Parietal lobe: Help in movements, the perception of stimuli
and orientation.
– Occipital lobe: It is related to visual processing.
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– Temporal lobe: This region is related to perception and

recognition of memory, auditory stimuli and speech.
The brain consists of two types of tissues: Grey matter and White matter.

1. Grey matter
2. White matter
The exterior portion of the cerebrum is called the cortex or the cerebral
mantle.

Cerebrum Function

The cerebrum is responsible for thinking, intelligence, consciousness

and memory. It is also responsible for interpreting touch, hearing and
vision.

♧ Thalamus
The thalamus is a small structure, located right above the brain stem
responsible for relaying sensory information from the sense organs. It is
also responsible for transmitting motor information for movement and
coordination. Thalamus is found in the limbic system within the
cerebrum.

♧ Hypothalamus
The hypothalamus is a small and essential part of the brain, located
precisely below the thalamus. It is considered the primary region of the
brain, as it is involved in the following functions:

1. Receives impulses
2. Regulates body temperature
3. Controls the mood and emotions
4. Controls the sense of taste and smell
5. Coordinates the messages from the autonomous nervous system
6. Controls appetite, peristalsis, the rate of heartbeat, and blood
pressure.
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B. Midbrain

♧ Tectum
The tectum is a small portion of the brain, specifically the dorsal part of
the midbrain. It serves as a relay center for the sensory information from
the ears to the cerebrum. It also controls the reflex movements of the
head, eye and neck muscles.

♧ Tegmentum
Tegmentum is a region within the brainstem. It is a complex structure
with various components, which is mainly involved in body movements,
sleep, arousal, attention, and different necessary reflexes.

C. Hindbrain

♧ Cerebellum
The cerebellum is the second largest part of the brain, located in the
posterior portion of the medulla and pons. Cortex is the outer surface of
the cerebellum, and its parallel ridges are called the folia. Apart from this
The main functions of the cerebellum include:

1. It senses equilibrium.
2. Transfers information.
3. Coordinates eye movement.
4. It enables precision control of the voluntary body movements.
5. Predicts the future position of the body during a particular
movement.
6. Both anterior and posterior lobes are concerned with the skeletal
movements.
7. Coordinates and maintains body balance and posture during
walking, running, riding, swimming.

♧ Medulla Oblongata
The medulla oblongata is a small structure present in the lowest region
of the brain. It mainly controls the body’s autonomic functions such as
heartbeat, breathing, and digestion. It plays a primary role in connecting
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the spinal cord, pons and the cerebral cortex. Also, it helps us in
maintaining our posture and controlling our reflexes.

♧ Pons
The pons is the primary structure of the brain stem present between the
midbrain and medulla oblongata. The main functions of the pons include:

1. Controlling sleep cycles.

2. Regulating the magnitude and frequency of the respiration.
3. Transfers information between the cerebellum and motor cortex.
4. Pons is also involved in sensations, such as the sense of taste,
hearing and balance.

◇ Brain works like computers

The human body functions very similarly to modern day computers — or

rather, computers are very closely aligned to the most complex
processing unit there has ever been, namely the human brain. Going
back to basics for a moment — any information processing system
consists of 5 main components — input, output, storage, processing and
program. We can draw parallels between the brain and computers for
each of these elements.

1. Input: Inputs are stimuli, data and objects that act as the
basis for action.

 In the machine world, inputs come through input devices like

keyboards, mouse, scanner, camera, microphone etc. They come in
different formats like images, text and structured data.

• For the human brain, input is provided through internal and external
stimuli. Input ‘devices’ for brain would include sensory cells (those
associated with seeing, hearing, touching, tasting), motor/muscle
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cells, and even some cells within the brain. These cells pick up the
stimulus provided and take it in for further processing.

2. Output: Output is the information or action that comes as

a result of processing the input.

• Output actions in the case of machines could be things like printing

something, adding numbers, projecting an image, solving a complex
problem based on an algorithm, identifying patterns etc.

• The output from processing that occurs in a human brain is obviously

more sophisticated and includes activities like controlling internal and
external muscles, sensory perception, managing internal bodily
functions (like blood pressure, heart rate, temperature), decision
making, problem solving, emotions, social behavior, etc.

3 Storage: This is the place where things like input

information, output information and programs are held.

• Computers have two types of storage. A short-term storage, which

we commonly refer to as RAM, that stores limited amounts of
information (data or programs) required by the computer to perform an
immediate task. And a long-term storage with much greater capacity
in the form of Hard Disk Drives, Optical Disks, Tapes etc.

• Very similar to this construct is the memory system of the human

brain. The brain’s short-term storage is called ‘Working
Memory’ which uses the brain’s memory and attention capabilities
in short bursts of time to perform the immediate task at hand (e.g.
remembering what the teacher is saying when taking notes in
class). Long term storage for humans is through their ‘Long Term
Memory’ or LTM function which enables them to store almost
unlimited amounts of information for an indefinite period of time. It
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includes memory (or storage) of things like specific events, factual

information and experiences.

4 Processor: This is probably the simplest parallel to

grasp. It refers to the central processing circuitry that
carries out instructions provided.

• In a computer, this is managed by its CPU,

• whereas for humans it is the Central Nervous System comprised of the

brain and spinal cord and their internal circuitry.

5. Program: Or ‘code’, in computer language.

 This refers to the intricate set of instructions that lay out what
requires to be done with the input in order to arrive at an output,
bringing together a set of functions that have to be performed, in
a defined order, within defined parameters.

 In humans, this code is executed via the neurons present in the

brain. The neurons make connections with each other through which
they pass on signals which are processed to achieve desired action,
the entire process controlled by the central nervous system. The
signal or information exchange happens through very critical nervous
system structures called Synapses.
 Computer programs run via machine code, which are patterns of bits
(i.e. binary units of information like ‘1’ and ‘0’). Similarly, a human
brain runs its ‘code’ via patterns of chemical or electrical signals
which are passed from one neuron to the next forming a neural
network.

Artificial Neural Networks (or ANNs) work exactly like the biological ones.
ANNs are a web of artificial neurons that send signals to each other.
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These networks function just like the brain, learning through seeing,
without needing to be specifically programmed.