Ch 1; General Principles Pt 2

Front 1

Absolute Threshold

Back 1

A measure of the smallest amount of stimulus energy required for a subject to reliably detect its presence

Front 2

Differential Threshold (just noticeable difference)

Back 2

A measure of the smallest change in stimulus level required for a subject to reliably discriminate the direction of stimulus change.

Front 3

Psychometric Functions

Back 3

Any plot relating to a quantifiable response to a physical measure.

Front 4

Normal Distribution

Back 4

A distribution in which scores fall symmetrically n predictably on either side of the mean score.

Front 5

What is known about the exact position of a threshold in relation to a stimulus

Back 5

It can change and is subject to some random fluctuation as a result of momentary variations in neural sensitivity arousal level ect.

Front 6

Method of Adjustment

Back 6

A psychophysical procedure in which subjects adjust the value of a stimulus to estimate their threshold.

Front 7

Method of constant stimuli

Back 7

A psychophysical procedure in which preselected stimuli are presented in random order over a series of trials; the subject makes a binary response after each trial. yes or no/1 or 2 (better than adjustment)

Front 8

Signal Detection Theory (STD)

Back 8

A theory of performance in psychophysical experiments in which subjects' decisions are determined by their sensory response and by a tendency to respond in a certain way. It recognizes bias.

Front 9

Yes/no task

Back 9

A psychophysical procedure in which only 50% of presentations contain a stimulus and the subject must respond "yes" or "no".

Front 10

Forced Choice Task

Back 10

A psychophysical procedure in which each presentation contains intervals, only one of which (randomly selected) contains the stimulus; the subject must select the correct interval.

Front 11

d-prime (d')

Back 11

A measure of stimulus sensitivity based on signal detection theory, it represents the increase caused by the presence of stimulus.