Sound localization acuity of the common marmoset (Callithrix jacchus)

Abstract

The common marmoset (Callithrix jacchus) is a small arboreal New World primate which has emerged as a promising model in auditory neuroscience. One potentially useful application of this model system is in the study of the neural mechanism underlying spatial hearing in primate species, as the marmosets visually occluded natural habitat in the forest would make sound localization an essential behavior for survival. However, interpretation of neurophysiological data on sound localization requires an understanding of perceptual abilities, and the sound localization behavior of marmosets has not been well studied. The present experiment measured sound localization acuity using an operant conditioning procedure in which marmosets were trained to discriminate changes in sound location in the horizontal (azimuth) or vertical (elevation) dimension. Our results showed that the minimum audible angle (MAA) for horizontal discrimination was on average 15{degrees} for band-passed Gaussian noise and 13{degrees} for Random Spectral Shape (RSS) stimuli, whereas the MAA for vertical locations was at 17{degrees} and 22{degrees} for band-passed Gaussian noises containing more and less high frequency energy, respectively.