Visual perception

Question 1

Absolute threshold

Answer 1

minimum amount of stimulus energy required for our senses to perceive the stimulus in normal conditions

Question 2

`Reception

Answer 2

stimulus energy is collected

Question 3

Transduction

Answer 3

Stimulus energy is converted by receptors cells (rods and cones) into electrochemical nerve impulses

Question 4

Transmission

Answer 4

receptor cells send impulses to primary sensory cortex

Question 5

Selection

Answer 5

Selecting useful information and omitting useless information to prevent sensory overload

Question 6

Organisation and interpretation

Answer 6

information reaches the brain where past experiences, motives values and context give the stimulus meaning

Question 7

6 stages of vision

Answer 7

1. Reception
2. Transduction
3. Transmission
4. Selection
5. Organisation
6. Interpretation

Question 8

3 biological factors that affect visual perception

Answer 8

Physiological makeup
Ageing
Genetics

Question 9

How does physiological makeup affect visual perception?

Answer 9

If any structures or neural pathways are damaged

E.g. colour blindness is due to structural issues of the retina

Question 10

How does ageing affect visual perception?

Answer 10

Maturing of our sensory perceptions

Question 11

Examples of visual perception issues due to ageing

Answer 11

Presbyopia - lens loses flexibility which means it is difficult to see objects up close

Floaters - tiny clumps of matter that float in the vitreous fluid

Cataracts - eye lens start to become cloudy due to breakdown of protein

Glaucoma - affects optic nerve which causes disruption to transmission, thus leading to poor vision

Macular degeneration - build of grainy deposits in macula (centre of retina) which results in inflammation

Question 12

How does genetics affect visual perception?

Answer 12

Inherited visual disorders can be passed down from parents to children

Question 13

What is a psychological influence on visual perception?

Answer 13

perceptual set

Question 14

What is a perceptual set?

Answer 14

A predisposition to see things the way they are according to certain preconceptions

Question 15

4 factors that influence perceptual set

Answer 15

Past experience

Context - environment which stimulus is observed

Motivation - what we want to see (food instead of fuel if we are hungry)

Emotion - depending on how we feel ourselves

Question 16

2 types of perceptual constancy

Answer 16

Size constancy
- even when the stimulus is further away we maintain the perception on the size of the stimulus

Shape constancy
- object maintains its shape despite changing the perspective its seen from

Question 17

4 types of Gestalt principles

Answer 17

Figure-ground organisation
- where images are organised into being the central object of attention and a background. These are separated by an imaginary contour e.g. camouflage

Closure
- when we perceive an object as whole despite it being incomplete

Similarity
- elements that are similar to each other are grouped together

Proximity
- when parts of pattern are close together allowing those close together to be seen as a group

Question 18

How can depth cues be classified?

Answer 18

Binocular depth cues
- using both eyes

Monocular depth cues
- one eye alone or both eyes together

Question 19

2 aspects of binocular depth cues

Answer 19

Retinal disparity

Convergence

Question 20

Retinal disparity

Answer 20

binocular depth cue

for objects within 6-7cm

when the brain compares and contrasts the 2 slightly different images because of the distance between the eyes

e.g. holding pen to your eye and focusing in and focusing away

Question 21

Convergence

Answer 21

binocular depth cue

for objects within 6-7cm

as an object comes closer, our eyes come closer together to keep the object centred in our retina.

Question 22

2 types of monocular depth cues

Answer 22

Accommodation

Pictorial depth cues

Question 23

Accommodation (depth cue)

Answer 23

Tension in ciliary muscles is received by brain to confirm location of object (greater the tension, closer the object)

Question 24

Pictorial depth cue

Answer 24

To create 3D perception of something 2D

Question 25

5 types of Pictorial Depth Cues

Answer 25

1. Linear perspective
   
   • parallel lines are made to converge as they extend along the page
2. Interposition
   - basically overlap (which object is closer)
3. Texture gradient
   
   • made to make surfaces appear to recede into the distance(blur)
4. Relative size
   - Object that is producing the largest retinal image is closer
5. Height in the visual field
   - portraying objects farther away as being closer to the horizon

Question 26

Social influence on visual perception

Answer 26

through formal education, people are able to learn how to interpret images relevant to their culture and society

Question 27

Ponzo illusion

Answer 27

Uses linear perspective and height in the visual field to make it seem like the more distant line is the longest

Question 28

Muller Lyer illusion

Answer 28

Arrowheads

Carpentered world hypothesis

Perceptual compromise theory

Question 29

Carpentered world hypothesis

Answer 29

we make 3D forms of each figure using familiar features of buildings to do so

This causes the arrow-headed line as the leading vertical edge of a building’s outside wall and thus closer to the observer

The feather tails is perceived as being further away due to

Question 30

Perceptual compromise theory

Answer 30

AIms to explain the Muller Lyer illusion

States that ‘closure’ is the reason (Gestalt principle) - we connect the bottom lines with the top lines - thus making the feather tailed seem longer since it has a longer connection

Question 31

How does the Ames room illusion work?

Answer 31

The ceiling is not parallel to the floor - it slopes upward

Observer maintains shape constancy which sees the person moving in a straight line rather than towards the back of the room

Size constancy is prevented due to the use of monocular depth cues

Thus, room-size constancy is used which means the room looks the same size but the person appears to grow rapidly in size