CONDITIONAL DISCRIMINATION IN MENTALLY RETARDED ADULTS: THE EFFECT OF TRAINING THE COMPONENT SIMPLE DISCRIMINATIONS

TLDR

The authors trained two intellectually disabled subjects on a two‑choice conditional discrimination by first establishing successive discrimination between sample stimuli with distinct reinforcement schedules, then attempting simultaneous discrimination between comparison stimuli via simple discrimination reversals, and finally using a procedure that presented whole sessions of a single sample‑comparison relation while gradually reducing consecutive trials and randomizing sample presentation to maintain both discriminations. Both subjects initially acquired schedule performance but failed to match arbitrarily; arbitrary matching was achieved only when a procedure that presented whole sessions of a single sample‑comparison relation and gradually randomized sample presentation was used, and removing the schedule requirement did not affect accuracy, with both subjects also demonstrating control over symmetric relations.

Abstract

Two subjects with retardation who exhibited generalized identity matching, but who had extensive histories of failure to acquire arbitrary matching, were exposed to a series of conditions designed to train separately the components of a two‐choice conditional discrimination. First, the successive discrimination between the sample stimuli was established by programming a different schedule of reinforcement in the presence of each sample stimulus. Schedule performance was acquired and maintained by both subjects, but neither acquired arbitrary matching. To train the simultaneous discrimination between the comparison stimuli, 1 subject was then exposed to a series of simple discrimination reversals and subsequently failed to acquire arbitrary matching. Both subjects acquired arbitrary matching under a procedure that maintained both the sample and the comparison discrimination by first presenting entire sessions composed of one sample‐comparison relation and then gradually reducing the number of consecutive trials with the same sample until sample presentation was randomized (schedule performance was maintained). Removal of the schedule requirement had no effect on arbitrary matching accuracy. Both subjects subsequently demonstrated control by relations symmetric to the trained relations.