Chapter 55: Sensation And Perception

Question 1

Name and give a brief description of our sensory systems

Answer 1

Visual system: allows us to see. Light activates visual receptors in eye where it’s converted into nerve impulses that send info to brain for interpretation in occipital cortex.

Auditory system allows us to hear. Sound waves are recieved by auditory receptors in ear and encoded being set along auditory pathway to brain which is interpreted in temporal lobe.

Proprioceptive system provide people with info about movement and orientation in space. Kinaesthetic info comes from muscles tendons and joints. Vestibular info comes from ear and provides info about head movements.

Somaesthetic system provides info about environment outside skin relating to touch pressure heat cold and pain.

Chemical system allows experience of taste and smell. receptors for taste found in taste buds on tongue for sweet sour bitter and salty. The sense of smell or olfactory sense depends on activation of receptors in nose by chemical in air. Olfactory nerve send info to olfactory bulb at base of brain.

Question 2

What is sensation

Answer 2

It is the process of receiving sensory information and refers to sensory experience that occurs after sensory stimulus is detected.

Question 3

What is perception

Answer 3

The process of interpreting and making meaning from sensory info is perception and refers to higher level of info processing.

Question 4

What are receptors

Answer 4

Cells specifically adapted to receive info from environment which can differ in sensitivity.

Question 5

What is the absolute threshold

Answer 5

It determines whether a stimulus is intense enough to lead to sensory experience.

If below threshold won’t generate a response and must act on receptor for certain time for activation.

Question 6

What is the differencial threshold

Answer 6

The size of increase in intensity that results in a noticeable difference called just noticable difference.

Question 7

What is transduction

Answer 7

The transformation of one form of energy to another.

Question 8

What is a receptor potential

Answer 8

A resting potential in receptor cells.

Question 9

What is a generator potential

Answer 9

Conversion of resting potential into action potential when stimulated and where receptor cells convert receptor potential.

Question 10

What is an action potential

Answer 10

All or nothing event that’s a graded generator potential as energy comes from stimulus.

Question 11

What is adaptation

Answer 11

The decrease in stimuli to prevent overstimulation.

Question 12

What is monitoring

Answer 12

Refers to brains ability to process incoming info very rapidly and below level of awareness.

Question 13

What are the indicators of orienting reaction OR

Answer 13

Bodily signs like increased muscle tone and movement of eyes head and body towards stimulus.

Vegetative signs are brief decreases in heart rate holding breath contraction of blood vessels in limbs decrease salivation and enlarge pupils

Sensory signs provided by increased sensory sensitivity

Question 14

What is habituation

Answer 14

Is a basic form of learning and causes ignorance of stimulus that certain response can be stopped. It refers to disappearance of OR after repeated stimulation by event initially triggered them.

Question 15

What is dishabituation

Answer 15

Is a form or OR that allows us to become aware of potentially important changes in environment that we have been accustomed to and response occurs before stimulus has been recognised and given meaning

Question 16

What is perceptual organisation

Answer 16

The process of sensory info that ensures attention is given to relevant or important info.

Question 17

What are the laws of perceptual organisation

Answer 17

Characteristics of stimulus: according to nature of stimulus some regarded as more important that influence way we perceive them

State of nervous system: nervous system has to be in state of readiness to perceive info.

Individual person characteristics and past experience: we interpret info received in terms of own experience.

Question 18

What is figure and ground

Answer 18

When we perceive visual info we organise it into meaningful relevant info called figure against less meaningful info called ground.

The relevant information or figure is at higher level of awareness than less important ground so figure is first to be processed further.

They can be reversed but requires more cognitive effort and is applied to other kinds of sensory info.

Question 19

Discuss contour closure and grouping

Answer 19

Contour refers to boundary or other features that seperate from figure and ground. The perception of contour depends on abrupt changes in brightness and colour which give contrast

Closure refers to tendency to complete something spontaneously so it had meaning. It depends on our experience in the world.

Perceptual grouping refers to tendency to group stimuli in a pattern or shape in a way that’s to help interpret them

Question 20

What are the 4 types of perceptual grouping

Answer 20

Principle of proximity is the tendency to group elements that are close together as though they represent a figure.

Principle of similarity is tendency to group elements that are similar in colour shape or texture as though represent a figure

Principle of symmetry is tendency to group elements in a way that creates a symmetrical or balanced figure

Principle of continuity is tendency to perceive stimuli in a way that elements that are continuous form a figure.

Question 21

What is spatial organisation

Answer 21

It explains why we see world in 3D height width and depth while image on retina is 2D width and height.

Question 22

What is perceptual constancy

Answer 22

Seeing things as having a certain size shape colour and brightness irrespective of changing conditions.

Is a perception error in that perception aren’t same as retinal info but necessary for effective functioning because they provide our world with stability.

Question 23

What are the 4 attributes of perceptual constancy

Answer 23

Constant size refers to fact that familiar objects are perceived as having constant size as long as there’s enough cues in environment to provide info a about distance and depth.

Constant shape or shape consistency depends on making a compromise between retinal image angle of objects and past experience.

Constant brightness means perception of brightness doesn’t change when conditions change.

Constant colour where our perception of Colour are constant despite changing conditions.

Question 24

What are illusions

Answer 24

Object or stimulus exists but perceived because objects attributes are combined and perceived incorrectly. Are perceived spontaneously.

Question 25

What is recognition

Answer 25

The process of recognition is an example of attributing meaning to something and occurs because we have built up store of concept and groups which we use to classify info that’s perceived.

Question 26

Explain concept of attention

Answer 26

Occurs at high level of awareness where we consciously decide what should be dealt with and is a form of conscious control over what’s perceived.

Question 27

What is parallel processing

Answer 27

The process of simultaneous perception of different sets of info.

Question 28

What are the determinants of attention

Answer 28

External determinants:

Intense stimuli
Size
Distance
Change movement contrast 
Repetition
Complex stimuli

Internal determinants

Attention attributed to things that hold personal importance and relate to aspects like individual disposition personality needs and interests.

A perceptual set which is a state of perceptual readiness that makes formation of certain perception and actions more likely than others and provides framework for seeing things and influence way we perceive situations and events.

Question 29

Discuss intersubjectivity of perception

Answer 29

Perception is process of creating meaning but isn’t a reflection of reality but rather our own interpretation of it. It’s a subjective process because meaning we give depends on individual disposition and experience.

Made known to others by conveying private perception through language where we use intersubjectivity to describe shared or agreed meaning of ways events in world are interpreted.