The study of developmental psychopathology, and autism in particular, promises to elucidate the role of social experience among typically developing as well as atypical groups of children. Our focus is upon the developmental implications of children's natural propensity to identify with the attitudes of other people. From early in life, children are moved to adopt the psychological stance of others, with far-reaching implications for the development of their thinking as well as relationships. Children with autism appear to be limited in this propensity. Therefore through studying the nature of this 'basic' abnormality among children with autism, and tracing the implications for their cognitive and social development, we gain unique insights into processes of typical development, as well as autism itself. We also study autism among congenitally blind children, for the reason that this affords a perspective on 'atypical autism'. A further component to our research is into relations between mothers with borderline personality disorder and their infants. This gives insight into the nature of both the character of personality disorder, and the transgenerational impact of psychopathology.