Three variables (diagnosis, location of cues, and mental age of learners) influencing stimulus control and stimulus overselectivity were assessed with eight autistic children (mean age 12 years) and eight average children matched for mean age. Among results were that autistic subjects tended to respond overselectively only in the extra-stimulus…

Negative priming was assessed to investigate what information persons with (n=18) or without (n=18) mental retardation access from distractors. All subjects showed automatic activation of both targets and distractors at a short time interval. After a long interval, only the subjects without mental retardation exhibited inhibition of the…

Children with mental retardation are particularly prone to failure on relational tasks such as oddity and match-to-sample, suggesting a differential sensitivity to relational information. This paper reports on several studies in which characteristics of stimulus arrays were enhanced. Results demonstrated the theoretical and practical significance…