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…

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…