Chapter 4 - Visual Perception

Question 1

What is the Absolute Threshold?

Answer 1

the minimum amount of stimulus energy needed for an observer to perceive a stimulus, in idea conditions, 50% of the time.

Question 2

What is Absolute Threshold of Hearing?

Answer 2

the ticking of a watch 6 kilometres away

Question 3

What is Absolute Threshold of Smell?

Answer 3

one drop of perfume in a large house

Question 4

What is Absolute Threshold of Taste?

Answer 4

one teaspoon of sugar dissolved in 10 litres of water

Question 5

What is Absolute Threshold of Touch?

Answer 5

the wing of a fly falling on the cheek from a height of 1 centimetre

Question 6

What is Absolute Threshold of Vision?

Answer 6

the flame of a candle 50 kilometres away on a clear, dark night

Question 7

Main parts of the eye

Answer 7

aqueous humour 
vitreous humour 
retina
fovea
blood vessels
optic nerve
blind spot
sclera
lens
cornea
pupil

Question 8

What are the six stages of vision?

Answer 8

Reception
Transduction
Transmission
Selection
Organisation
Interpretation

Question 9

Reception

Answer 9

Visible light enters the eye

Question 10

Transduction

Answer 10

Light is converted to electrical signals by photoreceptor cells in the back of the eye; photoreceptors are grouped into receptive fields that influence a single neuron

Question 11

Transmission

Answer 11

Signals travel via the optic nerve to the visual cortex in the occipital lobe

Question 12

Selection

Answer 12

Feature detector cells filter incoming visual information to avoid overwhelming the brain

Question 13

Organisation

Answer 13

Visual information is processed along ‘what’ and ‘where’ pathways

Question 14

Interpretation

Answer 14

The stimulus is combined with information from other parts of the brain to give it meaning