International Journal of Comparative Psychology

Several recent studies have emphasized the role of the maternal call in the attachment process in young nidifugous birds. Prenatal auditory stimulation (audition of sibling calls or self perception) is a determinant factor in the development of the attractivenessc of the maternal assembly call. However, little is known about the role of sibling calls after hatching. In particular, they may be involved in attraction  between broodmatesx and, in this way, they may compete with the maternal call during the development of attachment. These experiments were designed to test the value of postnatal audition of sibling calls (C). Several groups of chicks were placed in an operant conditioning paradigm in which the instrumental response allowed the birds to receive either auditory, visual raudiovisual stimuli. Results demonstrated that audition of sibling calls is appetitive but, surprisingly,the chicks did not evince a clear-cut choice for this stimulus over audition of a pure tone (T). Moreover, chicks were tested in a choice situation between two audiovisual stimuli. The visual stimulus was the vision of their own image in a mirror (V). In this choice situation between "V + C" and "V + T," chicks did not choose the "V-l-C" stimulus significantly more. Thus, these data, without denying communicative value to sibling calls, support the hypothesis that they do not play an important role in attraction between broodmates and that the main effect of their audition is an activating one.