Week 3

Question 1

Signal detection theory

Answer 1

No fixed threshold. In conditions of uncertainty sensory/psychological factors determine people’s detection. Expectations and motivations play role. Hold stimulus intensity constant at slightly above threshold. Identifies detect ability and response bias

Question 2

Hit

Answer 2

Signal plus noise

Question 3

Miss

Answer 3

No on signal plus noise

Question 4

False alarm

Answer 4

Yes on noise only

Question 5

Correct rejections

Answer 5

No on noise only

Question 6

Concept of distribution of neural activity

Answer 6

Amount never=0, varies all the time

Question 7

Detect ability

Answer 7

How different is stimulus and the existence of already existing neural activity (sensitivity)

Question 8

Decision rule(response bias)

Answer 8

Psychological input, motivational manipulations, amount of feeling

Question 9

Discrimination

Answer 9

By how much must 2 stimuli differ before an observer reports a difference

Question 10

Difference threshold experiment

Answer 10

2 stimuli presented and compared on each trial

Question 11

Standard stimulus

Answer 11

Unchanging

Question 12

Comparison stimulus

Answer 12

Varies systematically

Question 13

Difference threshold

Answer 13

Person says greater than 75%

Question 14

Point of subjective equality

Answer 14

Can’t tell difference,50%

Question 15

Just noticeable difference

Answer 15

Smallest change from standard that can reliably be detected

Question 16

Webers law

Answer 16

Size of JND in different experiments appears to be a constant fraction/percentage of the standard value

Question 17

Scaling (magnitude estimation)

Answer 17

How much is there

Question 18

Indirect scaling

Answer 18

Fechner. Start at threshold, find first JND, then combine 1st+2nd JNDs and so on. Assume webers law is true all JNDs are equal real amounts get bigger but same %

Question 19

Fechners law

Answer 19

Initial changes in magnitude above threshold lead to more rapid changes in perceived intensity than subsequent changes

Question 20

Direct scaling

Answer 20

Stevens approach. Directly map physical/psychological scales

Question 21

Magnitude estimation procedure

Answer 21

Present standard to observer and assign a value. Series of trials present standard with 1 set of comparison stimuli. Ask subject to assign values in magnitude to standard. Plot data actual magnitude-estimated magnitude

Question 22

Classical threshold theory

Answer 22

Ability to detect is limited by sensory threshold-minimal amount of energy required to activate receptors. Measured with constant stimulation either experiment or observer controlled. Can screen people for sensory/perceptual problems