« Everyone knows that advertising primarily targets our reptilian brain ».
This statement from the columns of a major French daily bears witness to the success of the notion proposed by American neuroscientist Paul D. MacLean at the turn of the 1960s. It is part of a general theory of the brain that relates a set of « primary » attitudes to an archaic part of our evolutionary heritage: sexual instinct, territorial defense, aggression…
Considered erroneous at the outset, and then scientifically obsolete, the « reptilian brain » has nonetheless enjoyed a formidable career, which we retrace here in an investigation that combines a study of its formulation, analyses of its circulation or re-appropriation – from Arthur Koestler to Michel Onfray, via Alain Resnais – and an ethnography of certain therapeutic circles that still today invite us to accept the « crocodile » hidden within us in order to live better.
Why and how does a false theory spread? As a borderline case, the « reptilian brain » provides a fresh perspective on the question of how knowledge is disseminated in culture, and thus on the relationship between science and society.
