Introduction to Psychology 10th Edition by Rod Plotnik,Haig Kouyoumdjian

Exercise 7

Our second question-At what point do we know a stimulus intensity has increased or decreased?-can be answered by measuring the smallest increase or decrease in the intensity of a stimulus that a person can detect 50% of the time; this is called a (a) _____. It has been found that the increase in stimulus intensity needed to produce a just noticeable difference increases in proportion to the intensity of the initial stimulus; this is called (b) _____ law.