ABSTRACT
A primary goal of early scientic psychology was to analyze conscious content by means of introspective reports. Structuralists believed that these reports could provide a valid and reliable conduit to the mind. e approach was later abandoned because conicting, subjective data led to irresolvable controversies (Boring, 1950, p. 403; Heidbreder, 1933, p. 145). e paradigmatic shi to behaviorism avoided problems of conicting introspective reports by limiting psychology to more easily veriable data. Psychophysical methods survived the shi to behaviorism because cognitive concepts were not dened by introspective
reports per se, but by the relation of introspective reports to veriable characteristics of stimuli. For example, a just noticeable dierence was not dened by the participant’s introspective report that a stimulus had barely changed. Rather, it was dened by the smallest amount of physical change of a stimulus that the participant correctly detected on a certain proportion of trials.
