Autism encompasses a set of pluralistic developmental behavioral interactions that are organized into patterns that are both characteristic of the autism diagnosis and unique to the individual. We discuss three aspects underlying the development of autism: nonlinearity, cusps, and the notion of “hidden” skills and deficits. Autistic characteristics may suddenly emerge from skills previously undetected. Because these skills are necessary but not sufficient for the development of other behaviors, they can be identified as behavioral cusps. Because these skills are “hidden” (not readily observed), identifying and assessing them is a challenge to researchers and clinicians. In this paper we discuss some typical hidden skills and deficits that may contribute to the development of autistic behavior and provide examples of how they function developmentally in autism. Early detections of these skills and deficits are crucial for establishing the behavioral developmental cusps for typical development and avoiding the cusps for the development of autism.
