Stereotypical behavior maintained by automatic reinforcement often does not result in harm but may be undesirable in some situations. In the current investigation, participants were 2 individuals who engaged in nonharmful stereotypical responses shown in an analogue functional analysis to be insensitive to social contingencies. After bringing…

Direct observational data were collected on the behavior of 26 elementary school-age boys with fragile X syndrome (FXS), the most prevalent inherited cause of mental retardation, during classroom academic activities. Findings indicated classroom engagement comparable to that of peers and not related to intrasubject variables such as severity of…

Four boys (ages 5 to 12) with developmental disabilities and severe challenging behaviors were evaluated using two functional assessment procedures: different analog probe conditions, and direct classroom observation of the child's behavior, antecedents, and consequences. Results raised questions about the reliability and ecological validity of…

This final report reviews the second phase of a life-span study of boys with fragile X syndrome (FSX), the most common known inherited cause of mental retardation. Males with the syndrome are more severely affected than females and in males, delays are usually evident in all the developmental domains, although cognitive and communication skills…