Ebook: Biology and Cognitive Development: The Case of Face Recognition

Johnson and Morton present a theoretically intriguing account of face recognition in the chick and the human infant. They argue that cognitive development (in any species) can only be fully appreciated in a biological context, and in making their case for the human infant brain development and ethology provide the context.

The ethological context is provided by the chick, which is biologically predisposed to follow its mother (or another moving object) shortly after hatching, and evidence is presented that the features of the object that the chick most prefers to follow bear some relationship to features of the adult hen’s head. The critical features cannot be too precisely specified since chicks have been known to imprint on such diverse objects as Konrad Lorenz and army boots (the sad case of Egbert, the army- boot chick, is recounted on page 66). In Johnson’s experiments chicks were as equally attracted to a stuffed duck as to a stuffed hen, and indeed, were just as likely to follow a stuffed polecat (Mustelu putoris). Fortunately, polecats are not likely to be the first objects seen by chicks in the world outside of the laboratory! Under normal circumstances this predisposition (‘Conspec’) ensures that the chick approaches its own mother, and the chick then learns about her particular visual characteristics through imprinting (’Conlern’) and so comes to recognize her.

The authors point out that innate and ’primal’ predispositions will vary from species to species. For instance, the cuckoo chick, reared by a different species, does not imprint on its host species in the sense that when adult it seeks out another cuckoo to mate with-maybe some biological mechanism which facilitates conspecific recognition comes into play after the young cuckoo leaves the host nest. Another example is the Japanese macaque, which lives in troupes that intermingle with other monkey species; perhaps for the young macaque facial characteristics of its own species have to be provided in some early appearing primal biological mechanism in order to avoid cross-species confusion.

Despite these species differences, most of the book is concerned to suggest that the two cognitive mechanisms are to be found in both the chick and the human infant, and they serve to orient the young to faces and to facilitate learning about individuals of the species. In the human infant the first of these mechanisms, ‘Conspec’, is subcortically mediated and its sole purpose is to ensure that the newborn orients towards faces. The other mechanism is ‘Conlern’, and its job is twofold: (1) to detect similarities between people’s faces, and (2) to detect differences between faces, in order that individuals can be recognized.