Perceiving sounds in the real world: an introduction to human complex sound perception

Arguably sensory systems, including audition, evolved allowing animals to navigate, find prey, avoid predators, mate, and, for some species, communicate. All of these essential functions require animals to determine objects in their environment. Vibrating objects produce a sound pressure wave that has the potential of informing an animal about these objects. Such acoustic information can make the organism aware of its immediate environment, provide useful information about that environment, allow for communication, and/or provide an esthetic value. However, sound has no dimensions of space, distance, shape, or size; and the auditory periphery of almost all animals contains peripheral receptors that code for the parameters of the sound pressure wave rather than information about sound sources per se. Thus, knowledge about sound sources gleaned from the peripheral neural code for the sound produced by a source is most likely computed in the brainstem and brain by means of an auditory neural computer. How this neural computer works and what other aspects of neural processing aid the computer is a mystery that is receiving a great deal of attention by many auditory scientists.