Gerlinde Höbel and Laurel Symes
Department of Biological Sciences, UW-Milwaukee, hoebel@uwm.edu, symes@uwm.edu
Humans perceive several sounds in close temporal succession as a single event originating from the location of the leading sound, a trick played by the auditory system to improve sound localization. Surprisingly, a visual cue associated with the leading sound enhances sound localization, while a visual cue associated with the lagging sound inhibits it, suggesting that auditory spatial perception in humans is a fundamentally multisensory process. Many animals also focus on leading calls. For example, a female frog will approach the source of the first of two calls in close succession, resulting in higher mating success for the leading male. Whether visual cues affect the expression of leader preferences is unknown, but the fact that communication is frequently multimodal (i.e., a frog cannot produce a call without inflating his conspicuous vocal sac) suggests that this might be the case. We explored whether audiovisual integration during sound localization is unique to humans, or a general feature of animal sensory perception by conducting playback experiments with female treefrogs in which we compared their responses to sound alone, or sound combined with a visual cue (an LED). Funded by the Research Growth Initiative, UWM.