Relativity in Human Judgment

People make judgments every day about all kinds of things. Exceptionally they have to make a long series of similar judgments – medical screening for cancer, marking examinations, screening baggage at an airport – and those successive judgments are related. An error in one is passed on to the next. When such a task is recreated in the psychological laboratory, the nature of that relation can be determined. An error in one judgment is passed on to the next, because each judgment serves as a reference point for its successor.
The psychological task is known as ‘absolute identification’. Different frequencies and loudnesses of sound, brightnesses of light, different colours and tastes are to be identified one at a time. Experiment has shown that people are unable to identify more than 5 different frequencies, loudnesses, brightnesses absolutely–that is, without comparison with some other frequency or loudness. This book identifies the nature of the relation between successive judgments and the biases that result. It will be of particular interest to psychologists engaged in the study of all kinds of judgment.