T1: Measuring experiences

Question 1

Sensation

Answer 1

1) bottom-up process

2) ability to detect stimulus.

Question 2

Perception

Answer 2

1) top-down process

2) giving meaning to a detected sensation.

Question 3

The Steps of the Perceptual Process

Answer 3

a) Stimuli:
Step 1 - environmental stimulus
S2 - reflection and transformation of light

b) Receptor processes:
S3 - Transduction

c) Neural processes:
S4 - Neural processing (network from the visual receptors -> retina -> back of the eye -> primary receiving area = cerebral cortex)

d) Behavioural responses:
S5 - Perception = awareness
S6- Recognition = meaning/category
S7 - Action = motor activity.

Question 4

Transduction

Answer 4

transforming light energy into electrical energy.

Question 5

Bottom-up processing

Answer 5

• data based

- stimuli based

Question 6

Top-down processing

Answer 6

• knowledge
• labelling
• often unaware
• more complex stimuli => TDP increases

Question 7

Approaches for study of perception

Answer 7

Psychophysics
Physiological approach /. Electrophysiology
Neuropsychology
Cognitive neuroscience

Question 8

Psychophysics

Answer 8

• Fechner’s methods of measuring perception
• relationship between stimuli and behavioural response
• Oblique effect (Coppola/Furmanski) = better vision for verticals or horizontals

Question 9

Electrophysiology

Answer 9

present a stimuli and measure brain activity

Question 10

Physiological approach

Answer 10

Relationship 1 = stimuli and physiological responses

R 2 = physiological resp. and behavioural resp.

Question 11

Neuropsychology

Answer 11

• brain process => perception

- affects of brain damage on behaviour

Question 12

Cognitive neuroscience

Answer 12

stimulus => brain process => perception (fMRI)

Question 13

Methods of measuring perception

Answer 13

• Measuring thresholds with psychophysical methods

- Estimating magnitude

Question 14

Absolute threshold

Answer 14

• minimum amount of stimulation necessary for a person to detect stimulus 50% of the time
• no distinct transition

Question 15

Difference threshold or JDI

Answer 15

• minimum difference/change that exists between two stimuli

Question 16

A higher sensitivity results in a

Answer 16

lower threshold

Question 17

What are Fechner’s methods of measuring perception with psychophysical methods?

Answer 17

a) Method of Limits
- experimenter increases/decreases stimulus intensity
- threshold = average of all crossover points (change from Yes to No)

b) Method of Adjustment
- participants increases/decreases intensity
- accurate and fast
- threshold = barely audible

c) Method of constant stimuli
- random order
- different intensities
- yes/no or same/different tally
- threshold = detection 50% of trials

Question 18

What are the two methods that together - constitute the Golden Standard for measuring perception with psychophysical methods?

Answer 18

a) Forced Choice Method
- verbal reports
- present two stimuli and choose the greater one
- absolute threshold = 75% correct interval chosen

b) Adaptive Testing/Staircase Method
- present whole stimuli range
- when stimuli is near threshold -> ascending until detection, then shift descending until no detection = reversal
- threshold = concentration when reversal occurs

Question 19

How does estimating magnitude work?

Answer 19

• psychophysical method developed by Stevens
• participant assigned values to perceived magnitudes of the stimuli
• direct scaling : relationship between perceived magnitudes and stimuli
• explains response compression and expansion

Question 20

Response compression

Answer 20

• intensity becomes greater than magnitude

=> lower ability to detect difference

Question 21

Response expansion

Answer 21

• as intensity is increased, perceptual magnitude increases even more
  => greater ability to detect difference

Question 22

Weber’s Law

Answer 22

• Stimulus = JND/ constant K
• sensation is a constant ratio
• liniar relationship

Question 23

Fechner’s Law

Answer 23

• magnitude of sensation increases proportionally to logarithm of intensity
• not liniar
• describes only response compression
• indirect scaling => discrimination ability
• states that all JNDs are equal (incorrect)

Question 24

Steven’s Power Law

Answer 24

• magnitude of sensation is proportional to stimulus magnitude raised to an exponent (power n)
• n < 1 = response compression
• n > 1 = response expansion