Concepts & Methods

Question 1

Very briefly, what is perception?

Answer 1

The formation of representations.

Question 2

What do illusions allow us to study?

Answer 2

The limits of perceptual processing and the construction of a perceptual world from outside evidence and internal knowledge.

Question 3

What is analogue representation?

Answer 3

Magnitudes in one system map into analogous magnitude in another system.

Question 4

What is symbolic representation?

Answer 4

Discrete symbols in one system denote states in another system.

Question 5

What is computation?

Answer 5

Manipulation of symbols according to a set of rules.

Question 6

What is representation?

Answer 6

The state of a physical system corresponds to the state on another physical system.

Question 7

What is studied to help us understand how we represent the world?

Answer 7

What brain areas do and how information is combined and used to create a perceptual world.

Question 8

Describe the ‘Two visual systems hypothesis.’

Answer 8

Extra-striate areas split into a pair of anatomically (and possibly functionally) distinct pathways.

Question 9

What is the dorsal processing pathway associated with?

Answer 9

Motion, direction and location.

Question 10

What is the ventral processing pathway associated with?

Answer 10

Colours, detail and objects.

Question 11

Which brain area is associated with the dorsal pathway?

Answer 11

Posterior parietal cortex.

Question 12

Which brain area is associated with the ventral pathway?

Answer 12

Occipito-temporal cortex.

Question 13

In relation to modularity, what is V1 associated with?

Answer 13

Edges.

Question 14

In relation to modularity, what is V4 associated with?

Answer 14

Colour.

Question 15

In relation to modularity, what is V5 associated with?

Answer 15

Motion.

Question 16

Briefly, how does fMRI work?

Answer 16

Head surrounded by magnetic detectors, tiny changes in blood oxygen level detected, learn about neural function.

Question 17

Briefly, how does electrophysiology work?

Answer 17

Electrodes are used to record directly from single cells or regions near cells.

Question 18

Briefly, how does transcranial magnetic stimulation work?

Answer 18

Temporality reduces brain function by inducing a large, localised magnetic field.

Question 19

Why are various techniques used to study perception?

Answer 19

To understand how, why and where the brain is able to perform the hugely complex processing involved in perception.

Question 20

What is modularity?

Answer 20

Different visual functions are computed in different brain areas.

Question 21

What 2 key things does psychophysics study?

Answer 21

How physical stimuli are related to perceptual phenomena, and the lawful relationships between these.

Question 22

What 3 relationships did Fechner want to investigate?

Answer 22

Physical stimuli and subjective precepts, world events and personal experiences, and physics and mind.

Question 23

Describe the method of adjustment.

Answer 23

Observers adjust intensity until a circle is just seen.

Question 24

Describe the threshold in the method of adjustment.

Answer 24

The average increment.

Question 25

Give an advantage of the method of adjustment.

Answer 25

Quick and easy.

Question 26

Give a disadvantage of the method of adjustment.

Answer 26

Thresholds are variable due to peoples’ different criteria.

Question 27

Describe the method of limits.

Answer 27

Test starts high and intensity is reduced reduced until perceived as not brighter, alternated with starting low and increasing intensity until perceived as brighter.

Question 28

Describe the threshold in the method of limits.

Answer 28

Average of transition points.

Question 29

Give an advantage of the method of limits.

Answer 29

Fast.

Question 30

Give 3 disadvantages of the method of limits.

Answer 30

Incremental change can be predictable and create bias, participants can habituate and get used to giving a particular response, and people set their own criteria.

Question 31

Describe the method of limits with a staircase.

Answer 31

Incremental changes until response changes, then direction of increment is changed, until intensity approaches a threshold value.

Question 32

Describe the threshold in the method of limits with a staircase.

Answer 32

The average of the last 5 or 6 reversals.

Question 33

Give 2 advantages of the method of limits with a staircase.

Answer 33

Fast, and bias and habituation can be corrected by interleaving staircases.

Question 34

Give 3 disadvantages of the method of limits with a staircase.

Answer 34

People set their own criteria, habituation and incremental changes can be predictable.

Question 35

Describe the method of constant stimuli.

Answer 35

Experimenter chooses a fixer number of stimuli of different intensities, each is presented a fixed number of times, and he observe is asked whether they see it or not (yes/no).

Question 36

Describe the threshold in the method of constant stimuli.

Answer 36

Stimulus intensity at a fixed point (often 75% yes).

Question 37

Give an advantage of the method of constant stimuli.

Answer 37

Thresholds are often very stable as each observer sees the same stimulus set.

Question 38

Give a disadvantage of the method of constant stimuli.

Answer 38

Many responses are required as when it’s easy people say yes so much.

Question 39

What is detectability?

Answer 39

The relationship between intensity of a stimulus and the probability it will evoke an experience.

Question 40

What is a detection threshold?

Answer 40

The minimum stimulation required to ‘just perceive’ a stimulus.

Question 41

What is a discrimination threshold?

Answer 41

Smallest difference between 2 stimuli needed to detect them as different from each other.

Question 42

What is the point of subjective equality?

Answer 42

Where participants perceive 2 stimuli as the ‘same’ and are responding by chance.

Question 43

What is the just noticeable difference?

Answer 43

The smallest difference between 2 stimuli that can be ‘reliably’ discriminated.

Question 44

What is the Y-axis for detection experiments?

Answer 44

50 - 100%

Question 45

What is the Y-axis for discrimination experiments?

Answer 45

0 - 100%

Question 46

Give the formula for Weber’s law.

Answer 46

JND/length = k

Question 47

What can 2AFC techniques use PSE and JND to investigate?

Answer 47

The bias and variability that makes simple visual proprieties change over space.

Question 48

What measures accuracy/bias?

Answer 48

PSE.

Question 49

What measures precision/variability.

Answer 49

JND.