For several decades, studies on the social dissemination of scientific knowledge have distinguished between a classic model of science popularisation, referred to as the “deficit model”, and other forms more often characterised by public engagement with science. This article examines the current forms of this “deficit model”, which remains widespread, based on a survey carried out between 2014 and 2017 on a public neuroscience event, Semaine du Cerveau (Brain Awareness Week). The many organisational and planning constraints, placed on this project designed by the scientific community, show that any study into the classic forms of popularisation must consider: an externalist approach (which takes into account actors, institutions, policies, etc.), a communicational approach (which addresses the problems raised by reformulating esoteric texts into a more accessible form) and the ways in which the representation of speakers at Semaine du Cerveau influences their practices. The deficit model must, in light of these consideration, be clarified and nuanced. The deficit model cannot be approached independently of the networks of relationships in which popularisation is practised, which despite being a semi-autonomous activity must take into account a multitude of social realities (such as the field of science, other spaces of symbolic production, the logic of contemporary cultural practices, and the need to resort to specific discursive devices which also depend on the particular cultural and social context in which they are used).