Bird song is of considerable general scientific interest because it has proved to be the single best model system, involving a naturally-occurring complex behavior, for (a) the study of learning, and (b) the study of brain-behavior relationships. In addition, there are many surprising parallels between bird song and human language, including developmental and neurological similarities. The present research approach is unique in considering the song communication system from a perceptual point of view. Previous research has focussed on the signals, and has generally ignored the transformations performed on these signals by the animal's sensory-perceptual system. This approach is incomplete and potentially misleading if the animals perceive their signal systems differently from humans, as is very likely the case for many animal communication systems, and for bird song in particular. Methods have been developed in recent years that allow a researcher to characterize the perceptual dimensions of a set of stimuli for an animal by training it to indicate the perceived similarity between a pair of stimuli for all possible pairs in the set. This approach and related methods will be used to map the perceptual dimensions of the song system of the Song Sparrow, a species with a particularly complex and varied song. To examine the role of experience in the development of normal song experience, birds raised with and birds raised without hearing normal species song will be compared. Preliminary data has shown that the latter birds sing an abnormal song as adults and it is expected that their song perception is abnormal as well. In addition, correlations between song experience, song perception and the relative development of song centers in the brain will be determined. Therefore this research will advance our understanding and increase the utility of this model system by providing information on the heretofore neglected perceptual side of song learning.
