The objective of my research is to gain a comprehensive understanding of the cognitive and neural mechanisms that underlie the goal-directed actions of people from average and special populations such as Down syndrome, autism, and Parkinson’s disease. My research focuses on three major themes: 1) selective attention; 2) perception-action coupling in individual and social action contexts; and, 3) cerebral specialization of cognitive and motor processes. It is my hope that once a detailed knowledge of the processes underlying behaviour has been developed, the scientific and clinical communities can work together to create the optimal rehabilitative, learning, and working conditions necessary to facilitate the performance of all members of society.