psyc unit 3 perception

7/30/2019 Psyc Unit 3 Perception

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Unit 3- Perception


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Sensation Stimulation of sensory receptors

Transmission of sensory information to the

CNS Process of detecting and encoding stimulus

energy into the world.

Sensory receptors are located in the sensory

organs e.g. eyes, ears and skin.


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Sensation Stimulation of the senses is an automatic

process resulting from sources of energy e.g.

light, sound or presence of chemicals forsmell of taste.

It is then transmitted to the CNS throughelectric impulses.


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Perception The brains process of organising and

interpreting sensory info to give it meaning.

Not automatic but an active process Begins with sensation but also reflects ones

experiences and expectations as it makessense of sensory stimuli.


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Concepts Relating to Perception1.Absolute Threshold

2.Difference Threshold

3.Signal-detection theory4.Sensory adaptation

5.Selective Attention

6. Illusion

7.Perceptual organisation


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Concepts Relating to PerceptionAbsolute thresholdthe weakest amount of

stimulus that a person can distinguish fromno stimulus at all.

The minimum amount of energy that we candetect . What does it take to activate a

specific sensory system?


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Concepts Relating to PerceptionAbsolute Thresholds

1. Visiona candle flame viewed from about

30 miles on a clear dark night.2. Hearing a watch ticking from 20 feet away

3. Taste 1tsp. of sugar dissolved in 2 gallonsof water.


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Concepts Relating to PerceptionDifference Threshold the minimum difference

in intensity required between two sources of

energy so that they can be perceived asdifferent.

Smallest difference requires to discriminateone stimulus from another.


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Concepts Relating to PerceptionDifference Threshold

Is it the same or different?

The stronger the initial stimulus, the greatera change must be for us to notice it


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Concepts Relating to PerceptionSignal Detection Theory - concept thatsensitivity to sensory stimuli depends on a

variety of factors besides the physicalintensity of the stimulus and the sensoryabilities of the observer e.g. fatigue,expectancy, alertness, motivation etc.


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Concepts Relating to PerceptionSensory Adaptation- process by which we

become more sensitive to stimuli of low

magnitude and less sensitive to stimuli thatremain the same e.g. background noises oradapting to a dark room.

Sensitization (positive adaptation)

becoming more sensitive to stimulation . Desensitization(negative adaptation)-

becoming less sensitive to stimulation


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Concepts Relating to PerceptionSelective Attention - the focus ofconsciousness on a particular stimuli while

ignoring others. Also shiftable i.e. moving your attention from

one stimuli to another if necessary.

Influenced by ones motivation and interests.


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Concepts Relating to PerceptionIllusion - sensation that gives rise to

misrepresentation

Are incorrect but not abnormal Occurs when two objects produce exactly the

same retinal image but are perceived asdifferent.


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Concepts Relating to PerceptionPerceptual Organizationprocess by which we

organise or make sense of sensoryimpressions.

Guided by principles or Gesalt laws of:1.Proximity - nearness, the perceptual

tendency to group together objects that arenear to one another.

2.Similarityperceptual tendency to group

together objects that are similar inappearance.


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Concepts Relating to PerceptionPerceptual Organization

Laws of Proximity & Similarity


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3.Continuitythe tendency to perceive a series

of points or lines as having unity.4.Common fate - the tendency to perceive

elements that move together as belongingtogether.


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Laws of Continuity


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Laws of Common Fate Components in sound act together. They tend to start and finish together They tend to change in pitch or intensity

together.


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Concepts Relating to PerceptionPerceptual Organisation

5. Closurethe tendency to perceive a brokenfigure as being complete or whole.

6. Smallness -Smaller areas tend to be seenas figures against a larger background


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Laws of Closure


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Laws of Smallness


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Figure Ground Perception-the tendencyto organise the perceptual field into stimuli

that stand out (figure) and those that areleft over (ground)


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Factors Influencing Perception1. Motives

2. Interests3. Person (self)

4. Target

5. Context


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Factors Influencing Perception1.Motivesunsatisfied needs or motives

stimulate individuals and may exert a stronginfluence on their perceptions.

2. Interestsfocus of our perception isinfluenced by our interest.

Individuals interest differ so what one

notices in a situation can differ from whatanother perceives


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Factors Influencing Perception3.Personthe characteristics of a person

influences how they perceive a stimuli. Themajor characteristics include:

a.Attitudesb. Mood

c. Self concept

d. Cognitive structure

e. Expectationsf. Past experiences

g. Motives


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Factors Influencing Perception4. Targetcharacteristics of a target affects

how it is perceived e.g. physical appearance motions, shapes, colours, attractiveness,facial expressions, similarity, proximity etc.

5. Context - the situation between theobserver and the target also affects the way

a stimuli is perceived e.g. social settings,time, work setting


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Illusion Provides insight into how our perceptual

process works.

Occurs when two objects produce exactly thesame retinal image but are perceived asdifferent.

Mller-Lyer Illusion

Two sets of arrows that exhibit the Mller-Lyer optical illusion. The set on the bottomshows that all the shafts of the arrows are ofthe same length


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IllusionPerceptual Constancy

Mller-Lyer Illusion


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Objects are perceived as constant orunchanging

The tendency for perceived objects to giverise to very similar perceptual experiences inspite of wide variations in the conditions of

observation (retinal image).


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Size constancyrecognising that that anobject remains the same size even thoughthe retinal image of the object has changed.

Shape constancy - recognising that anobject remains the same even though its

orientation to us changes.


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Size/Shape Constancy


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Size Constancy


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Shape Constancy


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Shape Constancy


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3. Brightness Constancythe recognition thatan object retains the same degree ofbrightness even though different amountsof light fall on it.

4. Colour Constancy -the tendency for a color

to look the same under widely differentviewing conditions


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Brightness Constancy


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Colour Constancy


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Illusion Experience is very important in resolving the

discrepancies between a retinal imageof anobject and its actual size, shape or

brightness.


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Stereotyping Assumptions that we make based on prior

experiences. An exaggerated belief associated with a category.

Perceptual shortcuts:

1. First impression

2. Viewing people as constant

3. Blaming the victim

4. Halo effect

5. Just like me


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StereotypingCharacteristics

Fixed rigid ideas

Oversimplification of a category or group ofpeople

Not supported by reasonable evidence

Can be favourable or unfavourable

Driven by motives


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StereotypingCauses

Socialisation

Media Cognitive Process

Role Models

Figures of authority


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StereotypingStrategies to Correct Incorrect Perceptions

Accept that people are different

Practice active listening

Provide feedback

Own your behaviour/feelings

Avoid stereotyping

Use inclusionary language Distinguish between overgeneralisations and

factual evidence

psyc unit 3 perception

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