ABSTRACT
Loudness, the perceptual correlate of sound intensity, is one of the main components of auditory sensation. However, the perception of sound intensity is not just a matter of determining how loud is a sound or whether one sound is louder than another. Sounds are largely characterized by variations in intensity across frequency and across time. To use speech as an example, vowel sounds are characterized by variations in intensity across frequency (e.g., formant peaks), and consonants are characterized (in part) by variations in intensity across time (e.g., the sudden drop in intensity that may signify a stop consonant, such as /p/). To identify these sounds, the auditory system must have a way of representing sound intensity in terms of the activity of nerve fibers and a way of making comparisons of intensity across frequency and across time. The purpose of this chapter is to show how information regarding sound intensity is analyzed by the auditory system. The chapter examines how we perceive sound intensity and discusses the ways in which sound intensity may be represented by neurons in the auditory system.
