social group communicates to developing children that they have exclusive moral rights to their bodies—in other words, moral ownership of their body. This entails control over both active (physical) and cognitive appropriation, the former being control over one's movements and actions and the latter being control over who can experience one's physical existence and when. Alternatively, Stanley Benn defined privacy in terms of a recognition of oneself as a subject with agency—as an individual with the capacity to choose. Privacy is required to exercise choice. Overt observation makes the individual aware of himself or herself as an object with a "determinate character" and "limited probabilities." Covert observation, on the other hand, changes the conditions in which the individual is exercising choice without his or her knowledge and consent. In addition, privacy may be viewed as a state that enables autonomy, a concept closely connected to that of personhood. According to Joseph Kufer, an autonomous self-concept entails a conception of oneself as a "purposeful, self-determining, responsible agent" and an awareness of one's capacity to control the boundary between self and other—that is, to control who can access and experience him or her and to what extent. Furthermore, others must acknowledge and respect the self's boundaries—in other words, they must respect the individual's privacy. The studies of psychologists such as Jean Piaget and Victor Tausk show that, as children learn that they can control who can access and experience them and to what extent, they develop an autonomous self-concept. In addition, studies of adults in particular institutions, such as Erving Goffman's study of "total institutions" such as prisons and mental institutions, suggest that systemic and routinized deprivations or violations of privacy deteriorate one's sense of autonomy over time. Self-identity and personal growth Privacy may be understood as a prerequisite for the development of a sense of self-identity. Privacy barriers, in particular, are instrumental in this process. According to Irwin Altman, such barriers "define and limit the boundaries of the self" and thus "serve to help define [the self]." This control primarily entails the ability to regulate contact with others. Control over the "permeability" of the self's boundaries enables one to control what constitutes the self and thus to define what is the self. In addition, privacy may be seen as a state that fosters personal growth, a process integral to the development of self-identity. Hyman Gross suggested that, without privacy—solitude, anonymity, and