Derived Conditional Position Discrimination in Individuals without Naming Skills

The Psychological Record - Derived conditional discrimination was evaluated in 2 men with mental retardation whose language was limited to gestural requests. In each conditional-discrimination...     

Conditional discrimination in mentally retarded adults: the effect of training the component simple discriminations.

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.     

Conditional discrimination in mentally retarded subjects: programming acquisition and learning set.

In Experiment 1, 3 subjects with retardation were exposed to two visual-visual arbitrary matching-to-sample problems each day. One conditional discrimination was presented under trial-and-error conditions, and the other was presented under a component training procedure. The latter began by establishing the comparison discrimination and its rapid reversal. The successive discrimination between the sample stimuli was established through differential naming. Then, sample naming was maintained in conditional discrimination sessions in which the same sample was presented in blocks of consecutive trials. Block size was decreased across sessions until sample presentation was randomized as in trial-and-error training (but with naming maintained). Two subjects initially learned only with component training. The performance of the 3rd subject was inconsistent across conditional discriminations. One of the successful subjects ultimately learned rapidly and consistently with trial-and-error procedures. Experiment 2 sought to demonstrate learning set in the other 2 subjects. Elements of the component training procedure were withdrawn over successive conditional discriminations. Ultimately, 1 subject nearly always learned under trial-and-error conditions, and the other learned under trial-and-error conditions combined with differential sample naming.     

ASSESSMENT OF STIMULI CONTROLLING THE REQUESTS OF STUDENTS WITH SEVERE MENTAL RETARDATION DURING A SNACK ROUTINE

This study assessed stimuli controlling requests during a snack routine after extensive request training with a delayed prompt procedure. During training sessions, one of three three-item snack groups was presented to 3 subjects with severe mental retardation. Assessment sessions involved (a) training conditions (all items were visible), (b) presenting two of three items from a particular group, or (c) presenting no items. One subject requested food items when no food items were present, 2 frequently requested a missing item when the two other items were visible, and all subjects requested visible items. Procedures for assessing stimulus control, such as those described in the current paper, should lead to a better understanding of the variables controlling behaviors that initially appear perplexing and unpredictable.