What Is a Difference Threshold (Just Noticeable Difference)

Multiple Choice

What is a difference threshold (just noticeable difference) ?

A) The smallest amount of change between two stimuli that an individual can detect 50 percent of the time.
B) The smallest amount of physical stimulation that an individual can detect 50 percent of the time.
C) The largest amount of physical stimulation that an individual can detect 50 percent of the time.
D) The smallest amount of physical energy that an individual needs to be able to carry out a weight-lifting task.