Lecture 4 - How do we measure the detection of differences between stimuli?

Question 1

Difference Threshold

how to test?

Answer 1

It is the smallest detectable difference between two
stimuli. It is called the just-noticeable difference (JND).
Also known as DL (Differenze Limen).

• You present an observer with two stimuli: a “standard”
and a comparison stimulus.

• The standard remains at the same value, but the
comparison can vary along some dimension (e.g. weight,
sound intensity, light intensity, etc.).

Question 2

point of subjective equality (PSE)

Answer 2

If stimuli are below this threshold, we say they are at a…

Question 3

Early on, it was noticed that the value of DL (JND) increases with

Answer 3

the magnitude of the standard stimulus

Question 4

Weber’s Law

Answer 4

DL/S = K

Question 5

Weber fraction (K)

Answer 5

remains stable for a given sense, but isn’t the same across senses

it’s a constant relationship not a constant amount