Even today, some people still think it is somehow degrading to humanity to regard it as part of the lineage of living creatures formed by the evolutionary process. In this study, illustrated with a profusion of examples, Rolf Schäppi refuses to oppose phylo-genesis, socio-genesis and psycho-genesis. Instead, he formulates the principles of an evolutionary psychology that can serve as the foundations of the many disciplines that place humankind at their centre, either as the subject or object of study. As he points out, although human beings are both mammals and primates, they differ in many significant ways from the other mammals and primates. Besides speech, laughter and the ability to use tools, the species Homo sapiens differs from its closest zoological cousins by three additional characteristics, which are less frequently cited because they are found only in the female. These are the female silhouette, hidden œstrus and the menopause.

Rolf Schäppi is a psychiatrist and ethologist. Since 1972 he has been in charge of a seminar on ethology, in Geneva's university institutions on psychiatry.