Self-knowledge is based on several different forms of information, so distinct that each one essentially establishes a different 'self. The ecological self is the self as directly perceived with respect to the immediate physical environment; the interpersonal self, also directly perceived, is established by species-specific signals of emotional rapport and communication; the extended self is based on memory and anticipation; the private self appears when we discover that our conscious experiences are exclusively our own; the conceptual self or 'self-concept' draws its meaning from a network of socially-based assumptions and theories about human nature in general and ourselves in particular. Although these selves are rarely experienced as distinct (because they are held together by specific forms of stimulus information), they differ in their developmental histories, in the accuracy with which we can know them, in the pathologies to which they are subject, and generally in what they contribute to human experience.