We report on the case of a patient with frontal-temporal damage from cerebral hypoxia, affected by amnesic disturbances and behaviour disorder, who presented a peculiar phenomenon of environmental dependency. He assumed a different social role in keeping with different environmental circumstances by interpreting a character corresponding to the particular context. Three experiments were carried out in which the environmental variables were manipulated to verify the phenomenon in controlled conditions, and an investigation was conducted during the patient's spontaneous manifestations. The phenomenon was interpreted as a loss of frontal inhibition whose function was the control of his own identity and consequent “attraction” towards a social role proposed by the environment.