The author uses historical evidence to argue that tests are instruments of social control and not just of psychological investigation. Tests perfectly illustrate Michel Foucault’s point about the close connection between the science of psychology and technologies of control. To study a person, one needs to objectify his or her individuality and subjectivity. But, having become an object of investigation, the person becomes an object of forms of social control more subtle than violent or repressive actions but no less efficient. Reduced to figures, categories and diagnoses, a person is easier to manage and manipulate. Psychologists therefore should take into account that psychology is as much a technology of managing an individual, a part of bureaucratic practices, as a science.