Stimulus over-selectivity is a phenomenon often displayed by individuals with many forms of developmental and intellectual disabilities, and also by individuals lacking such disabilities who are under cognitive strain. It occurs when only one of potentially many aspects of the environment controls behavior. Adult participants were trained and…

Four of eight low-functioning, developmentally delayed preschool children initially failed to demonstrate expected oddity responding. In the context of a multiple baseline across-subject design, each of the previously unsuccessful children demonstrated significant increases in the percentage of correct oddity responses immediately upon…

This study examined the matching and sequencing of quantities, numerals, and arbitrary forms by two individuals with mental retardation. Results showed that sequence training did not readily lead to new matching performances, unlike prior research with college students. Instead, training in matching to sample yielded emergent sequence production…