Shedding light on the origin of specific neuronal mechanisms for processing acoustic stimuli is important to understand the evolution of primate communication. One of those specialisations, lateralised processing of speech in humans, is a well established finding. Evidence is accumulating that diverse animal taxa also show hemispheric asymmetries in the perception of conspecific sounds. Rhesus macaques (Macaca mulatta), for instance, exhibit a right head-turning bias in response to playback of natural conspecific vocalisations, and a left head-turning bias in response to one heterospecific stimulus and several manipulated conspecific calls. This finding was related to a hemispheric specialisation for processing conspecific versus heterospecific vocalisations. We conducted orienting experiments with Barbary macaques (M. sylvanus) living in the enclosure ‘La Forêt des Singes’ in Rocamadour, France. In contrast to rhesus macaques, our subjects showed no orientation preferences in response to conspecific or heterospecific vocalisations. These results add to the puzzling mosaic picture of orienting asymmetries in different mammalian species and, in conjunction with other studies, highlight the importance to substantiate the assumption of a strong coupling of orienting bias and hemispheric asymmetry.

(Teufel et al., in press)