Sensation and Perception

Unit-3

 (Sensation and perception)

Sensation: Meaning, Importance, Sensory Threshold, Habituation and adaption,

Types of Sensory Experiences, Structure and functions of Visual and auditory Sensation

Perception: Definition and Characteristics, Perceptual Processes (Pathways in Brain and Top Down and Bottom-Up Processing) Subliminal and extra sensory Perception, Theoretical explanation of Perceptual organization (Gestalt Principles) Perceptual Ambiguity and distortion.

Social Cognition and Behaviour  : Process of Social Cognition, attitude, social Influence, prejudice and discrimination.

Sensation/Perception and Attention

Ø  Sensation is the detection or awareness of physical energy in the environment due to the stimulation of sensory receptors present in the sense organs

Ø  Attention is process that compels us to select some particular stimuli out of no. of stimuli present in environment

Ø  Perception is the meaningful interpretation of sensory information.

or,

Ø  perception is the process through which we select, organize and interpret sensory information

Sensation is regarded as the pre awrness.

Ø  Sensation is the detection or awareness of physical world through sensory receptors present in the sense organs.

Ø  Sensation is the stimulation of the sense organs that comes from our initial encounter with stimuli (forms of energy that activate sense organs).

Ø  Sensation is the process by which our senses gather information and send it to the brain. 

Ø  Sensation is the input about the physical world provided by our sensory receptors.

Ø  Everything we do is depending upon information encoded in message from our receptors (sense Organs).

Ø  Receptors are often referred to as gateways to knowledge, which provide information about the world around us.

Ø  Sensation is a pre awareness of any stimulus without reference to its meaning.

Ø  A primary source of knowledge of the external world

Ø  It helps to bring external information into body and to the brain.

Ø  It helps to makes a clear and appropriate interpretation and meaning in perception process

Ø  It is also called passive because it does not consciously engage in sensing

Ø  It is simple and meaningless, a prior condition of interpretation.

Ø  Each sense organs are programmed to receive different types of sensation

A large amount of information is being sensed at any one time such as

Room temperature,                     Brightness of the lights,

Someone talking,                          A distant vehicle sound, or

The smell of perfume,                People stepping outside the room

Hunger pangs in our stomach, Internal ache.

But,

We do not have the same power of smelling as our dog has.we cannot see in the dark but cat is capable of doing it. We don't notice radio waves, x-rays, or the microscopic parasites crawling on our skin. Similarly, the light or sound waves that are beyond our sensation can be successfully caught by our television set.

IMPORTANCE OF SENSATION

1.      Sensation process is the first process of gaining knowledge of the world around us.

2.      It is the single source to detect the stimulus of outside world.

3.      Sense organs have contact with reality.

4.      Mind is empty at the birth. The process of sensation and perception helps storing experience, knowledge, and information of the outside world.Without sensation perception does not occur.

5.      Sensation helps in survival.

6.      Sensation makes aware of ourselves (eg: pain, touch, smell, sound, dark etc)

PROCESS OF SENSATION

External world (stimulus) stimulate the sense organs

There are receptor cells in sense organs and they become activated

Each sense organs are activated by different types of stimulus (e.g., eyes by light, ear by sound, etc)

The stimulus or information is changed to neural impulse by sense organs

These neural impulse are received and carried by neuron to brain centers

When neural impulses reaches to the brain centers, the process of sensation ends

Identifying, recognizing, and understanding the stimulus is not the function of sensation. It is the function of perception.

SENSORY THRESHOLD

Sense organs have functional limitations. We cannot detect, notice, hear, see, and taste the sensation if they are at certain distance. To be noticed, hear, see, feel etc. stimulus should be within a range, or at least stimulus carry a minimum value. The lowest value of a stimulus that can produce a sensation is called a threshold.

1.Absolute Threshold:(Reis Limen or, RL)

Absolute Threshold is the smallest intensity of the stimulus to be noticed by the receptors. People have RL for Light, Sound, Taste and Smell.

Example of Absolute Threshold for human being:

Ø  Vision (sight) - A candle Flame at 30 miles away on a clear dark night.

Ø  Auditory (Hearing) - The tick of a watch can be heard 20 feet away in a quite condition.

Ø  Taste (Gestation)- One spoon of Sugar dissolved in 2 gallons of water.

Ø  Olfaction (Smell) – One drop of Perfume diffused in three room apartment.

Ø  Coetaneous (Touch) – A bee’s wing falling from a distance of one centimeter.

Differential Threshold (DL or j.n.d)-

Ø  The minimum difference to be noticed as difference is called DL.

Ø  It can also be found in all kind of Sensation Example- For vision, taste, hearing, smell and touch.

Ø  It is the amount of Stimulus to be added or subtracted from the existing Stimulus for a person to notice differences( for just noticeable differences or j. n. d)

Webers law- People have the ability to notice small change in weak stimuli and large changes in the intensity of strong stimuli. But,They cannot detect small change in large stimuli. Eg- it is difficult to notice 105 kg of Rice is heavier than 102 kg.

Adaption/Habituation

Sensory Adaption is the reducing Sensitivity to an unchanging Stimulus.

Eg- Entering Cinema hall people feel dark but after a while people can even recognize other sitting Audience. Similarly, but after the movie outside the hall, the bright sunlight causes eyes to blink but after sometime it goes normal. (The Rods and Cons receptors of eye help us to adapt) Similarly Deeping hand into the cold water, we feel cold and complain how cold it is but later on it goes all right.(The thermo receptors in the skin adapts to the temperature of the water. The same process happens in our other senses as well. The constant exposure to a stimulus causes our nerve cell fireless frequently. Sensory adaptation is an adjustment in sensory capacity

Sensory Adoption or Habituation has several benefits:

Ø     It provides attention in change Environment. It enables our sensory receptors to be alert to the situation and adopt accordingly. Sensory adoption allow us to free out attention to focus on more important things..However, sometimes sensory adoption is harmful in the case of Smoke or harmful chemical.

Habituation is a form of learning where organism learns to stop responding to a stimulus which continuously presents. Habituation is a decrease in response to a stimulus after repeated presentations. For example, a novel sound in your environment, such as a new ring tone, may initially draw your attention or even become distracting. After you become accustomed to this sound, you pay less attention to the noise and your response to the sound will diminish. This diminished response is habituation.

Here,Sensory Adaption and habituation is same.

Types of Sensation:Sensation are broadly divided into three types:

1. Exteroceptors: The sensing organ located at the outside parts of the body and excited by external environment. (it is concerned with light,sound,smell,touch and test sensation.
2. Proprioceptors: The sensing function is located at and around muscle and joints. It is concerned with movement of muscle.(kinesthetic Sensation)
3. Interceptors: The sensing Function is located inside the body and excited by the internal stimuli. Hunger, thirst, sex ..

Types of Sensory Experiences according to our sense organ

1.      The visual sensation-Eye

2.      The Auditory sensation-Ear

3.      Somatic sensation -The skin Sense, touch ( Coetaneous )

4.      Gustatory sensation , Sense of smell-nose

5.      Taste-Tongue

Others (Body senses)

Vestibular (sense of Balance) Kinesthetic Sense (sensation of body movement and position)

1.Visual Sensation

Eye is the window to the living organism to see the world. The process of receiving the information from the environment through the eyes is called Visual Sensation. Most of the stimuli in the environment are received through eyes. Therefore, in the process of sensation inhuman, the visual sensation is given the most importance. It is the work of light that makes the stimuli in the environment visible. The length of waves is measured through Nanometer. It is in the eye that light energy is converted into a neural code understandable to our nervous system. It involves different chain of actions to make us see the world.

The chain of actions to make us see the world .

a)    Cornea- As Light rays enters the eyes ,first pass through the Cornea (a transparent protective window/helps to focus on light waves)

b)    Transparent area that allows light to pass into the eye.

c)      Anterior Chamber- The light waves than enter into a open area called the “Anterior Chamber” (where it passes through a clear watery fluid called Aqueous Humor)

d)    Aqueous humor Continuously recycles and provides nourishment to the eye.

e)     Pupil- Light then enters to the Pupil. Pupil is a round opening whose size varies with lightening conditions: the less light present, the wider the pupil opening. These adjustments are executed by the Iris.

f)       Iris - is the colored membrane around the pupil, which changes shapes to arrange the size of pupil to adjust the amount of light into the eye...

g)      Lens -   Lens is a clear structure whose shape adjusts to permit us to focus on objects at varying distances. When we look at a distant object, the lens becomes thinner and flatter; when we look at a nearby object, the lens becomes thicker and rounder.

h)    Retina - Light rays leaving the lens, enters the Retina at the back of the eyeball. The millions of receptor cells of Retina Convert light energy into neural Impulses. These impulses are sent to the Brain and construct into a perceived image.

The retina contains two types of light sensitive receptor cells:

Ø  Cones- All together there are about 5 million of Cones. Cones function best in bright light and plays key role both in color vision and in our ability to notice fine details. Cones are located in the central area of retina called as Fovea.

Ø  Rods- There are about 120 million Rods. Rods are found outside fovea, and help us to see in darkened room or at night.

Ø  Fovea- It is the Centre of Retina, which helps our vision to make clear and fine. The retina is covered with two basic types of light –sensitive cells- rods and cones. The cones cells are sensitive to color and are located in the part of the retina called the fovea. Where the light is focused by the lens.

Ø  Blind Spot and Optic nerve- It is the point in Retina from where sensory message coded by reting transfer to the brain.

2.Hearing Sensation

Another most important organ in sensation is the Ear. Ear plays the next big role in receiving information from the environmental Stimuli. Social interaction, language development, music etc are not possible without the ear. During the process of Hearing, ear converts the sound waves into Action potentials in the auditory nerve fibers. The link between how we hear and what we hear is possible through sound waves. (Sound waves are the vibration of moving air).These waves are molecules of air, travelling at approximately 750 mile/hr.

a)     Outer ear (pinna) - The external part of the ear called “pinna”  which collects sound waves where hearing process begins to take place.

b)     External Auditory Cannel- It is connected between outer and middle ear, the sound waves in the auditory canal strike the Eardrum to vibrate.

c)      Eardrum- Eardrum is the 1^st Structure of the middle ear) it is the thin membrane stretched across the inner end of the Auditory canal.(the pressure of the sound wave cause it to move which inturn hit and vibrates three bones called the hammer, the anvil and the stir up. Which transmits the energy to the inner ear.The vibrating stirrup which is attached, with oval window transmits and the energy to it?

d)     Oval Window- It is a thin membrane of cochlea. Connects to the middle ear with inner ear. It strikes the liquid filled snail shaped cochlea of the inner Ear.

e)     Round window-it is just below the oval window and tries to equalize the pressure in the inner ear

f)       Cochlea –It is a liquid filled snail shaped in the inner Ear.

g)     It contains multilayered membranes and two long tubes that double back on themselves.)

h)     The vibration of the liquid in the cochlea causes sound energy to reach basilar membrane.

i)       Basilar Membrane- It is a structure which is covered with hair cells. These hair cells are the receptors of sound stimuli. These auditory receptors in the cochlea or fluid, translates the message in to a neural impulses and  pass it to the brain.(Before passing to the brain the auditory receptors causes the neurons with them to fire.

2.The Chemical Senses

Senses of Smell and of Taste are called Chemical Sense. Both are said to be activated by Chemical Stimuli.

3.Sense of Taste

The gustatory receptors are located in tongue and throat known as buds. Taste Buds are small bumps called papillae. Most of the buds are located in the tip, sides and back of the tongue. Some are found in back of the throat, roof of the mouth and inside the cheeks.

Each of these so called Taste buds contains approximately 20 test cells, a cluster of taste receptors.

Human beings possess about 10,000 taste buds. These help to detect a large number of tastes in food. The food we eat dissolve in saliva, are than pass through these taste pores to the cells responsible for taste detection. And ultimately the taste sensation in the language of neural impulses is sent through axon of taste cells.

Mainly there are 4 primary tastes:

Sweet, Sour, Salty and Bitter. And all other tastes results from a combination of these four qualities.

The receptors of taste are not evenly distributed over the tongue but are grouped in different areas. At the middle of tongue there are no receptors at all.

The Back (both sides) of the tongue is sensitive for - sour,

The tip is for- sweet

Side of tip (both) – salt and

Back side- bitter.

Taste sensation is maximum in infants and decreases with age especially after 45.

4.Sense of Smell

When a substances molecules mix in the air  our olfactory receptors located at the top of the nasal cavity are active. The molecules then react the receptors cells ,“Cilia are the hair like substances, which are projected in the olfactory epithelium.

Human beings have about 50 millions of these receptors and can detect approximately 10,000 scents, while dog can detect many more because they have more than 200 million receptors.

The receptors of Celia convert the molecules in Neural Impulses. The Axon of the receptor cells carry the smell sensation in the form of neural impulses directly to the olfactory bulbs in the brain and as a result we experience a particular Smell.

5.The skin Sense

The senses of skin work together to provide the information of objects we encounter. They warn us against potential danger to our bodies. The group of Skin includes three Senses:

Ø  The sense of touch or pressure

Ø  The sense of pain

Ø  The sense of Temperature(warm and Cold)

The Receptors of Skin Senses:

Ø  Free Nerve Endings- it is just below the surface of Skin. They are involve in all the three kind of Skin Sensation.

Ø  Basket Nerve endings- These receptors represent the nerve fibers that wrap around the base of the hair. They are more responsive to the stimuli carrying touch or pressure sensation.

Ø  Encapsulated end organs- the third type of skin sense receptors represent those nerve fibers that end inside some sort of cells.(they are found to be sensitive to pressure and temperature)

All these different kinds of skin sense receptors send typical skin sensory message to the brain through the spinal cord.

The message from the left side of the body is transmitted to the right cerebral hemisphere and from the right side of the body to the left hemisphere.

1.Touch and pressure- we experience touch or pressure not only when object presses on the skin but also when hairs of the body are moved or touched.The most sensitive regions are the finger tips, the lips, the genitals, the sensitivity in other area is considerably less.Blind people use touch pressure and smell sensation much more than the normal people.

2. Temperature (Hot and Cold)-

The sense of Cold and Warmth are experienced through different Spots. Which are situated in different places of skin. One set of spot detects warmth and other detects coldness. When the skin is warmed by hot water, air or sunlight the warm spot receptors are active and send messages about the feelings to the brain. Likewise if we feel cold, the cold spot receptors react and send messages to the brain. The object at least 1 or 2 degree centigrade warmer or colder than body temperature is sensed as hot or cold.

But,

In the case of Extreme hot Sensation both the hot and the cold receptors are active and send message to the brain giving sensation of hotness. But it is not same in Extreme cold. A wide variety of skin receptors are called thermo receptors.

3. Pain (coetaneous sensation)- It is caused by different unwanted information of hot and cold, toxic Chemicals, and Cutting problem with the skin. The receptors of pain are free nerves ending. The general receptors of pain is nocio receptors.

As we experience the pain, the receptors convey the message to spinal cord thus the neurons of spinal cords send messages about the pain to the brain.

Body Senses

As chemical sense includes taste and smell, Body sense includes vestibular and kinesthetic and coetaneous sense.

1. The kinesthetic Sense- The word kinesthetic is originated from the greek word “kinesis” which means movement. It is also known as muscle senses/the sensation of body movement and position and sixth sense. There is no one specific organ for kinesthetic sensation .The kinesthetic receptors are scattered in all over the skins, muscles, joints and tendons. They helps us to walk, bend, talk, write run etc..

It works to maintain a certain posture such as: to dance, walk, type etc. These senses play a key role in relaying information about the position and movement of the part of body without observing or seeing them through our sense of vision.

2.The Vestibular Senses-It is also known as somato sensation. It is located in the inner ear. It provides information about the body’s orientation and movement. It is composed with two small sensory structures: the three semi circular canals and the utricle and saccule.

Each semicircular canal is filled with a jelly like fluid. This fluid contains sensory receptors, as a fluid moves in the canal it causes hair cells in canal to react. The activation of these hair cells sends information about movement of the body to the brain.

v  These receptor cells respond to any movement or rotation of head. (they provide left,right,up down front back information on orientation of body)

v  This cell responds to the changes in their position of the head with respect to the direction of gravity. 

v  These receptor cells helps the brain to identify the position of the head with respect to gravity

Eg- helps us to run without falling,

Walk in between two poles..or in swing bus.

When the vestibular sense receptors are stimulated harshly or abruptly it may cause dizziness and Nausea.(eg- when we are in boat, running vehicle)

Perception

Our Sensory Receptors are bombard continuously by various stimuli present in the environment. As a result we become aware of some light, sound or chemical stimuli by experiencing some sensation. Our eyes makes us aware only of some light stimuli, It does not recognize them, “book, mobile phone or,  bag” Our ears are aware of some auditory stimulation but cannot tell us that is  the Horn of Bus or whistling of Train or birds twittering.

The question arises:

What happens inside the central Nervous system??

How are we helping in analyzing, identifying, classifying, interpreting and deriving the meaning of awareness of stimuli? In other words, how is our brain able to organize the transmitted sensory coded message in meaningful pattern? The answer top such question is “perception”.

Definition of perception

Charles G . Morris,”perception is the first event in the chain which leads from the stimulus to the action.”

Edmund Fantino and G.s Renolds, “perception is the organizing process by which we interpret our sensory input”.

CHARACTERISTICS OF PERCEPTION:

q  Perception is the complex mental process.

q  Perception is the process of obtaining knowledge of external objects and events by using the means of sense organ.

q  Perception interpret sensory information in meaningful pattern.

q  Perception makes us aware of our environment and surroundings.

q  Past experience plays vital role in perception or, identification of object.

q  Perception has quality of discriminating stimuli.eg- sound of vehicle/animal.

q  Some time we may have errors in perception/ false perception .

q  Perception differs according to individuals age, sex, educational level etc..

PERCEPTUAL EXPERIENCE (Pathways in Brain and top-down and bottom-up processing),

Perception occurs when sense organs receive stimulus and neurons carries them to brain centers. The ! question is which process forms the basis of this received information into perceptual experience. Is it

the stimulus information that makes perceptual experience or the previous experience, expectation, attitude, etc that forms the perceptual experience? There are two perceptual processing theories to explain perceptual experience:

Gibson's (1966) Bottom Up (or Direct) Theory of perceptual process.

•       It states that perceptual experience occurs as it goes from bottom to up level (sense organs, neurons, brain)

•       It states perception'depend on stimulus itself. It is a data-driven processing. Processing depend on stimulus information

              stimulus à receptors  of sense Organ à Neural Impulsesà brain.

Gregory (1970) Top-Down (or Indirect) Theory perceptual process.

•       It states that perceptual experience occurs as a result of experience, knowledge and expectation of the perceiver.

•       It is guided by higher-level knowledge. It goes with the motto 'we see the world as it is.

Perceive in meaningful pattern and functions.

Perception of the stimuli in brain (meaningful)à Motor Neuron carries informationà (Different Glands, Muscles, Skins, Joints)  and function accordingly.

Psychologist refers sensation as Bottom up process and perception as  Top down process Because they are constructed not only. On the basis of What our senses detect but also our experience and expectation.

SUBLIMINAL PERCEPTION

Subliminal stimuli are any sensory stimuli below an individual's threshold for conscious perception.Perception of or reaction to a stimulus that occurs without awareness or consciousness. It is also called 'subception'.It happens when mind receives stimulation from our senses that is not strong enough to register in our conscious minds.

EXTRA-SENSORY PERCEPTION

Extrasensory perception is perception in which our senses does not involve. Phenomenon like telepathy, clairvoyance or supernormal awareness of objects or events not necessarily known to others; and precognition or knowledge of the future.

•      Many psychologists are skeptical of extrasensory perception but many also believe in it

•    No creditable theoretical explanation is found.

PERCEPTUAL ORGANIZATION

Definition: The process by which we structure the input from our sensory receptors is called perceptual organization.

Ø It is a tendency to perceive sensory elements as well organized, meaningful whole rather than as separate, isolated parts.

Ø A process of proper arrangement and meaningful organization of pieces of information. Example: A chair with 3 feet will be perceived as a chair though it is incomplete (part is missing).

Ø This idea was given by Gestalt psychologists (Max Wertheimer, Kurt Koffka and Wolfgang Kohler).

Laws of Perception and Perceptual Groupings

Perception organizes the stimulation; it interprets the patterns and gives them meaning. The question here arises how does this perceptual organization takes place.

This phenomena was first studied properly by a group of German psychologists known as the Gestaltists.The German word Gestalt means “Configuration, totally or whole”.

They founds that individuals tend to organize environmental stimuli into some meaningful patterns or wholes according to certain principles.

The gestalt psychologists demonstrated that we organize our perception by grouping elements. Our mind follows certain rules to bring order and form to these basic sensations.

Eg- the letters in any organized form in some specific slide, book or page is known as words. Which usually carry the meaning. The process of perceiving is therefore the process of perceptual organization. Perceptual organization integrates sensation in to meaningful units.

Gestalt psychologists argued that in perception the whole is greater than sum of its sensory parts,

Eg- Figure and ground Grouping.

Ø  Principles of grouping: It refers to the tendency to perceive stimuli in some organized meaningful patterns by grouping them on one.

Ø  Similarity: Similar objects or stimuli are usually perceived as a unit.

Ø  Proximity : Nearness of objects or stimuli are likely to be perceived as belonging to the same group. Continuity: Objects or stimuli are perceived as a unit or group on the basis of their continuity.

Ø  Figure and ground: A Figure has a definite shape and a location in space; and Ground, has no shape and definite location and continues behind the figure. Figure is perceived in relation to its background. The world is more meaningful with F/G.

Ø  Other principles: Principle of contrast, Principle of simplicity, Principle of context.

1.Similarity: The Brain tends to group similar elements together.

Objects that are similar in color , size or shape are usually perceived as a part of a pattern.

Or, In an organization, all Employees who wear blue  dress may perceived a common group while in reality, each worker is a unique individual. Or, Women are perceived as a single group.Similarity is stronger than proximity.

Or,

Other stimuli that have different features are generally not perceived as part of the object. Our brain uses similarity to distinguish between objects that may lie next to other based upon their visual texture. An example of this is a large area of land used by numerous independent farmers to grow crops. Each farmer may use a unique planting style which distinguishes his field from another. Another example is a field of flowers which differ only by color.

2)Proximity: The brain tends to group together objects that  are close to one another.

It describes the tendency to perceive objects that are close to one another as being grouped together in a meaningful way. The supervisors may perceive the group as a trouble making if the output is low even, when some of the workers are dedicated or loyal to organization.

Or,

The principle of proximity states that, all else being equal, perception tends to group stimuli that are close together as part of the same object, and stimuli that are far apart as two separate objects. This allows for the grouping together of elements into larger sets, and reduces the need to process a larger number of smaller stimuli. For this reason, people tend to see clusters of dots on a page instead of a large number of individual dots. The brain groups together the elements instead of processing a large number of smaller stimuli, allowing us to understand and conceptualize information more quickly.

3. Continuity- If possible, the brain organizes stimuli into continuous lines or patterns rather than dis continuous elements.

This principle says that we perceive continuous flowing line more easily than broken lines.

On the organizational setting continuity may not lead to innovative or creative ideas or attitude to the workers.

3.Closure: people tend to perceive incomplete figures as complete .or, If part of familiar pattern or shape is missing, perceptual, process complete the pattern, to create a complete whole object.

Sometimes in an organization project is given ,but there may be the opposition from several members. but later on,the members with in the group close the existing gap in between the members and complete the task.The mind simply fills the gap  to perceive familiar pattern.

Or,

The principle of closure refers to the mind’s tendency to see complete figures or forms even if a picture are incomplete, partially hidden by other objects, or if part of the information needed to make a complete picture in our minds is missing. For example, if part of a shape’s border is missing people still tend to see the shape as completely enclosed by the border and ignore the gaps. This reaction stems from our mind’s natural tendency to recognize patterns that are familiar to us and thus fill in any information that may be missing.

Closure is also thought to have evolved from ancestral survival instincts in that if one was to partially see a predator their mind would automatically complete the picture and know that it was a time to react to potential danger even if not all the necessary information was readily available.

 

5.Principle of Figure Ground Relationship

Figure ground relationship is concerned with perceiving figure. It involves distinguishing an object from its surroundings.

Here, figure is perceived in relation with its background.

Ø  A tree is a figure that appears against a background of sky.

Ø  Similarly the words are figures that appear on the back ground of a page.

We perceive a figure against a  background or background against a figure depending upon the characteristics of the perceiver and the strength of figure/ground.Sensory experience other than visual experiences may also be perceived as figure and ground.

Example :

•      While eating a meal that test too salty will perceive salt as figure and curry as a ground.

•      While listening news in radio set considered as figure and other noise in room as ground.

Gestalt psychologists have devised ambiguous figure-ground relationships — that is, drawings in which the figure and ground can be reversed.

 

Images of Figure and Ground principle

(Perceptual ambiguity and distortion)

perceptual Ambiguty is “when recognition and interpretation of sensory stimuli based chiefly on memory is tricked by 2 images that are closely combined with each other”

Errors in Perception

        I.            Illusion

      II.            Hallucination

   III.            Delusion

Illusion is the wrong interpretation, incorrect perception, mistaken or distorted perception, subjective perversion of the objective contents of sense perception.

Misinterpretation of the sensory information.

Eg- perception of snake while seeing rope in darkness. Our past experience, our fear, and the darkness, helps to perceive the rope as the snake because the rope and snake have similarity in structure. Illusion may occur because of confusion, eye movement, perspectives, emotion, defects of sense organs etc..

1.Illusion of size- This type of Illusion provides false perception of the size of the objects. For eg- The electricity pole  in nearby distance  may be perceived larger than one in the far. Despite the fact that the size of pole is same.

2.Illusion of length –Muller-lyer illusion-  Though the both line are in equal length the bottom line is perceived longer.

3.Illusion of Perspective- pozono Illusion -The rail way Track on the top looks longer than bottom one.

4.Illusion of Curvature-  Although both the parallel and straight line are straight ,seems bowed.

 

5.Horizontal and Verticle Illusion- Vertical seems longer than Horizontal.

6.Illusion of Movement – quite often ,we perceive movement when the objects, we are looking at, are actually not moving at all. Such faulty perceptions are called illusion of movement.

   

Delusion

Delusion is the conventional belief that the person might be expected to hold given by his educational and cultural background.Delusion are beliefs that are held with great conviction and cannot altered by presenting evidence that contradicts them.

Eg- Person who has been brought up to believe in Spritualism is unlikely to change his conviction when presented with contrary evidence that convince a non- believer.

Types of Delusion-

Ø  Delusion of Persecution- People against me.

Ø  Delusion of Grandeur- I am God. or Almiety

Ø  Delusion of Reference- People talking about me.

Ø  Delusion of Control- Somebody is controlling me.

Ø  Somatic Delusion- Insect crawling in by body.

Ø  Self Condemnatory Delusion- Finding oneself as    unworthy, valueless , trust less.

Hallucination

Hallucination is the sensory perceptions in the absence of external Sensory stimuli.

For example:

Thus Hallucinations are classified as

o   Auditory- An individual hears a voice when there is no sound,

o   Visual- Likewise sees non –existed objects,

o   Olfactory- Smell non- existed scents.

o   Gustatory - Taste and feels not –existed stimuli.

Process of Perception/ Perceptual process

PROCESSES (General) OF PERCEPTION

1.      Receptor process (sensing through sense organs and neural process; code physical energies to chemical impulses).

2.      Unification process (organizes information received from sense organs).

3.      Symbolic process (use of past experience, schema, mental pictures to interpret and understand the sensory information).

4.      Affective process (feeling and emotion in relation to the stimulus).

1. Receptor process- Receptors are the specialized cells of Nervous system that are sensitive to stimuli. When the information reaches to the sense organ the receptors of sense organ activate and start to response, this process is called receptors process. Example-several receptor process are simultaneously activated.

If you saw your friend called you.

q  Seeing her, your receptors of the eyes active,

q  Hearing the sound the auditory receptor active to transfer the information and give it a meaning.

q  Similarly shaking hands with her activates the receptors of skin.

q   The smell of her perfume activates the receptor of nose. and so on. (Then u response accordingly)

2. Symbolic Process- Symbol is the process of perception in the absence of actual stimuli.Symbolic process is any process which is a substitute. Neural activities aroused by stimulation leave engram (memory traces) in the nervous system. This may then represent or act as substitute for the original situation.Symbolic images are formed by the neural activity in nervous system in the absence of the actual activity or stimuli .Perception involves more than simply activating the sensory receptor cells it uses the: language,concept,images,odor, past experience, schema, mental pictures to Interpret and understand the sensory information.

3. Affective Process – we not only simply perceive the object or situation it also has affective experience.

Affective process is the feeling, the sentiments attached to an object or person. (Each perceptual experience has its affective aspects)

While perceiving we do not only have the images of an object but also its impression as pleasant - unpleasant, liked - disliked, interesting- uninteresting, love-hate, for or against or perhaps none of these. All these affective process depends upon the past experience.

For example, needle prick, scolding, electric shock, aggression, hatred, sickness produce feelings of unpleasantness, friendliness usually arouses pleasant experiences.

4. Unification Process- organize information receive from sense organ altogether this is called unification process.

Or, This process states that all the processes of perception are needed to have a clear picture and understanding of what we perceive.

Attention

We are always surrounded by multiple Stimuli. It is impossible to react to all the stimuli of the environment at any given moment. Some of them must be filtered out. We must be selective.

Matlin and Foley, “Attention is the process of Focusing perception to the limited number of stimuli.”

Dumville, ‘’Attention is the concentration of consciousness upon one object rather than another”

We respond (focus our Attention) in terms of our interests, attitudes, motives, selectively, voluntarily and involuntarily.

SOCIAL COGNITION AND BEHAVIOR

Social Cognition
Cognition is a higher mental process in which the information is obtained, processed, transformed, stored, retrieved and used.

SOCIAL COGNITION: It refers to the ways in which we interpret, analyze, remember and use the information about social world. It describes the ways how we think about other people, society and world around us.

Social cognition is the encoding, storage, retrieval, and processing, of information about the members of the same species. The perception, judgment, and memory of social stimuli or, the effects of social factors on information processing.

SOCIAL COGNITION :It refers to the ways in which we interpret, analyze, remember and use the information about social world. It describes the ways how we think about other people, society and world around us.

Social cognition is the encoding, storage, retrieval, and processing, of information about the members of the same species. The perception, judgment, and memory of social stimuli or, the effects of social factors on information processing.

Social Cognition examines thinking, Eg-

Ø  How we perceive/think about others?

Ø  How we Solve problems,

Ø  How we Make decisions,

Ø  How our attitude and prejudice formed?

Ø  How we Combine information from memory and current experience,

Ø  How we Use language to Communicate our thoughts to others.

The process of social Cognition

Ø  Gathering Information/ Integrating the information.

Ø  Making Judgment of Social Stimuli (attitude or predudice)

Ø  Deciding what information to use.

SOCIAL BEHAVIOR

Social behavior focuses on how individuals respond to their environment.While living together/ people share and gain experience and attempt to influence others behavior to adjust in that particular society.

Person’s Social Behavior can be change for social adjustment .which can be influenced by - friends, religious groups,politics, parents, peers, media etc.

Attitude: nature, characteristics and importance

Ø  Attitudes are the belief system  that directs our thoughts, feelings, and actions with regard to other people, situations ,objects etc .Attitude may be positive or negative.

Ø  Attitudes are shaped by the exposed information- like or dislike, pro or anti, favoring or not favoring and positive or negative or neutral (ambivalent).

Ø  Attitudes evaluate or provide judgment based on past information or impressions. Example people have different attitudes towards different issues like: AIDS, religion, abortion, politicians, suicide etc..

Ø  Attitudes are learned behaviors and many times it becomes habit- we repeat it again and again. It is also a perception, a way of viewing others and finally attitudes are judgment, a rigid approach to something.

Ø  An attitude is "a relatively enduring organization of beliefs, feelings, and behavioral tendencies towards socially significant objects, groups, events “(Hogg & Vaughan 2005)

Structure of attitudes:

It has 3 components also called ABC model of attitudes (LaPiere, 1934):

1.Cognitive component: lead the individual to belief in certain way(positive/negative/Neutral.

For example: "I believe snakes are dangerous".

2.Emotional component: this involves a person's feelings / emotions about the object.

For example: "I am scared of Snakes".

3.Behavioral component: are the tendency to act in certain way as directed by the cognitive and emotional components. It shows the readiness to behave.

For example: "I will avoid snakes and scream if I see it".

Meaning of Persuasion and Ambivalence:

Ø  PERSUASION: Persuasion is the pressure to convince others to change their attitudes or behavior. It is a form of social influence used in daily social life.It plays vital role to shape our attitude.

Ø  Ambivalence refers to the fact that our evaluations of objects, issues, people, events are not always uniformly positive or negative; on the contrary these evaluations are mixed, consisting of both positive and negative reactions. For example, people like chocolate desert (a positive evaluation),but they also think it too rich and too fattening (negative evaluation), They refuse to eat. Their attitudes were reflected in their behavior, these reactions were ambivalent in nature, and the negative component was dominant.

Determinants/Development of Attitude:

Ø  Attitudes are shaped by the exposed information: Culture,religion,parents, friends, siblings, and teachers influences the attitudes similarly text books, TV, news paper also shapes attitudes.

Ø  THE GENETIC FACTOR: Identical twins are more closely related in their attitudes than non identical twins or siblings .(Tesser, 1993).

Ø  LEARNING FACTOR : Different evidence and exposure with different situation.

PREJUDICE

Ø  Prejudice is preconceived opinion that is not based on reason or actual experience.

Ø  Prejudice is an attitude (feel, think, and act). It has affective, behavior and cognitive aspects.

Ø  It is usually negative and Aimed toward biased groups.Prejudice leads to discrimination

Ø  Prejudice is prejudgment, or forming an opinion before becoming aware of the relevant facts of a case. The word is often used to refer to preconceived, usually unfavorable, judgments toward people or a person because of gender, political opinion, social class, age, disability, religion, sexuality, race/ethnicity, language, and other personal characteristics.

SOURCES/Determinants  OF PREJUDICES

Ø  SELF-ESTEEM: People hold prejudice views because they feel themselves superior in various ways and putting down negative views towards the other groups.

Ø  COMPETITION: Prejudice develops out of the struggle over jobs, adequate housing, good school, and other beneficial outcomes. People want and value good jobs, nice homes, high status, which are not available to all.

Ø  LEARNING AND SOCIALIZATION PRACTICES

Ø  ROLE OF MEDIAS:

SOCIAL INFLUENCE:

Social influence is the efforts made by the individuals to change the attitudes, beliefs, perceptions and behavior of others. Change in an individual’s attitude and behaviour occurs because of interpersonal contact, sharing of opinions etc..

Social influence includes:

_a)               Conformity

b)     Compliance

c)      Obedience

d)     Intense indoctrination

a)Conformity: Accepting the Views of the Public Conformity is behaving in the ways that are liked and accepted by friends, societies, or groups.People accept social norms in order to be liked by others. Social norms may be spoken and unspoken.

Spoken-(written) and

 Unspoken-"Don't stand too close to a stranger"

"Don't arrive at parties exactly on time".

“Follow current and rapidly changing standards of dress, speech, and fashion.”

B. Compliance

There are some situations of social influence which leads them to behave in ways that are not in their best interest. People have these type of situation in everyday life.

For example,

Ø  If you want someone to do something for you, how would you make others to agree with you?

Ø  If you go on exploring these circumstances for a moment, you'll realize that you have some tricks of your own to get compliance that enables other person to agree to your requests.

Compliance is the descriptions of such techniques. These tactics depends upon the situation.

Example- Salespeople, advertisers, fund-raisers, politicians, professional negotiators, and many others. People are often unaware that they are being influenced.

c. Obedience:

Obedience is a good thing. It enhances a society by putting together its members to obey laws, rules, and customs.

d. Intense Indoctrination

Intense indoctrination is a process through which individuals become members of extreme group and come to accept the beliefs and rules of the group in a totally unquestioning and highly committed way.