Foucault derives the concept of panopticism from a diagram drawn up by the British philosopher Jeremy Bentham in 1791. Bentham’s Panopticon was a model prison in which supervisors could observe prisoners in their individual cells without being seen themselves. According to Foucault, this system was effective because prisoners never knew whether or not they were being watched: ‘he is seen, but he does not see…what matters is that he knows himself to be observed’ (Foucault 1977a: 201). Foucault goes on to argue that this constant sense of surveillance and visibility is what characterizes the development of disciplinary societies in toto. In such a society, ‘the automatic functioning of power’ is guaranteed because individuals police themselves and each other.