This target article by Estes (1950) sparked the mathematical learning
theory movement, which took seriously the goal of predicting quantitat
ive details of behavioral data from standard learning experiments. The
central constructs of Estes's theory were stimulus variability, stimu
lus sampling, and stimulus-response association by contiguity, all cas
t within a framework enabling predictions of response probabilities an
d latencies. The math models enterprise nourished during the period 19
50-1975 and provided successful quantitative accounts of data from Pav
lovian and instrumental conditioning, probability learning, verbal lea
rning, concept identification, and other standard learning paradigms.
The techniques have been assimilated into the armamentarium of theoret
ical psychology. Stimulus sampling theory has faded away as it has bee
n transformed into modern descendants such as connectionism and inform
ation-processing models of cognition.