ABSTRACT

This chapter examines some of the impediments to vocal communication that may have shaped the fundamental properties of the standard plan of primate oral communication systems. It explains cross-species comparisons of the perception of speech, species-specific calls, and synthetic signals in an attempt to ascertain the extent to which humans and other animals are listening to the world through common or individualized perceptual systems. The impediments to vocal communication encountered in the modern world are insignificant with respect to the evolution of speech and aural perception systems. Although the machinery and congestion of the modem industrialized world produce high and annoying levels of ambient noise, the natural world also exhibits prominent sources of noise. The problem of frequency-specific attenuation and scatter potentially confusing vocal-tract transfer functions and changes in articulation may be reduced if inflection or intonation contour variations are employed as the parameter for vocal elaboration.