Unit 3 Topic 2 - Visual perception

Question 1

Describe the process of sensation in relation to vision (3.2.1.1)

Answer 1

Reception: stimulus energy is collected by eye

Transduction: stimulus energy is converted by the receptor cells into electrochemical nerve impulses

Transmission: receptor cells send the nerve impulses to the primary sensory cortex where specialised receptor cells respond as the process of perception begins

Question 2

Describe the process of perception in relation to vision (3.2.1.1)

Answer 2

Selection: pick out the most important and meaningful stimuli to focus on

Organisiation: the information reaches the brain and is organised so we can make sense of it

Interpretation: our past experiences, motives, values and context give stimuli meaning

Question 3

Differentiate between sensation and perception (3.2.1.1)

Answer 3

Sensation - biological, physiological, bodily processes

Perception - physiological, psychological

Question 4

List and describe the biological influences of visual perception (3.2.1.2)

Answer 4

Ageing: ability to perceive and interpret changes

Genetics: heritable genetic disorders

Psychological Make-Up: damage or impairment of structures of the visual system - related to psychological structure of the eye

Question 5

List and describe the psychological influences of visual perception (3.2.1.3)

Answer 5

Past Experiences: affect visual perception - significant personal meaning

Context: environment of the stimulus - immediate effect on our expectation

Motivation: we see what we want to see

Emotion: depends on our feelings

Question 6

Define perceptual set (3.2.1.3)

Answer 6

• predisposition to perceive stimuli in a specific way
• interpreting what we see according to certain preconceptions

Question 7

List and describe the perceptual constancies visual perception principles (3.2.1.3)

Answer 7

size constancy: maintain constant perception of an objects size

shape constancy: object maintains is shape despite change in perspective

Question 8

List and describe the gestalt principles visual perception principles (3.2.1.3)

Answer 8

figure ground organisation: whats infront and behind

camouflage: figure blends with surroundings

closure: perceive object as whole when it is actually partially incomplete

similarity: individual parts are similar

proximity: stimulus pattern are close together

Question 9

List and describe the depth perception visual perception principles (3.2.1.3)

Answer 9

Binocular Depth Cues:
- retinal disparity: each eye has slightly different view
- convergence: eyes move together to centre stimulus
Monocular Depth Cues:
- accommodation: adjust focus depending on position
- pictorial depth cues: 3D perceptions that are 2D
>linear perspective
>interposition
>texture gradient
>relative size
>height in vision field

Question 10

Summarise

Hudson (1960)

(3.2.1.4)

Answer 10

AIM:
- determine the effect of culture on pictorial depth perception

METHOD:
- tested 85 factory workers from different backgrounds, educational levels and degrees of urbanisation
- showed picture of hunter and 2 animals
- image contained depth cues (overlapping + size constancy)

RESULTS:
- education and culture influence images
- higher education correctly identified ‘prey’
- children who attend school see 3D image

SIGNIFICANCE:
- culture does effect depth perception

Question 11

Summarise

Deregoski (1972)

(3.2.1.4)

Answer 11

AIM:
- investigated whether pictures are seen and understood in the same way in different cultures, ‘are picture universal?’

METHOD:
- western v african cultures (indep. measures)
- exp 1: recreation of Hudson (1960)
- exp 2: construct the shown image
- exp 3: ambiguous trident

RESULTS:
- specific cultural skill which is learnt and not automatic
- africans thought images were only 2D
- westerns thought images were 3D

SIGNIFICANCE:
- different cultures influence the way in which images are seen and understood

Question 12

Summarise

Deregoski, Muldrow and Muldrow (1972)

(3.2.1.4)

Answer 12

AIM:
- investigate recognition of pictures by remote populations who had trouble in recognising familiar objects

METHOD:
- used ‘low-land’ and ‘high-land’ groups which each had different exposures
- presented 3 pictures (standing buck, running leopard, Hudson image)

RESULTS:
- differences observed between groups (some groups had greater familiarity)
- concluded perception is mostly based on past experience or familiarity
- skill can be learnt

Question 13

Explain the Müller-Lyer illusion (3.2.1.5)

Answer 13

The points are distanced at the same length apart however the illusion makes people believe one point is further away than the other
Relates to visual perception principle of closure

 <------>
 >------<

Question 14

Explain the Ames Room illusion (3.2.1.5)

Answer 14

The room is trapezium shaped and designed to create false distance cues
When viewed through peephole (using one eye only), the room appears to be rectangular
The illusion restricts monocular vision which is the basis of the illusion

Question 15

Explain the Ponzo Visual Illusions (3.2.1.5)

Answer 15

The yellow lines appear to be different sizes, however, they are the same length
Relates to visual perception principles of linear perspective and height in vision of field

Question 16

Explain the impossible figures (3.2.1.5)

Answer 16

Type of optical illusion involving 2D images that are perceived as 3D (cannot exist in 3D form)

Question 17

Explain the ambiguous figures (3.2.1.5)

Answer 17

Exploits visual similarities (manipulation of Gestalt principles), multistage perception (two or more unchanging images)