1. Introduction
In its most common sense, acoustic communication occurs between animals,
but in special cases it may occur within individual animals in the context of
autocommunication. Communication can be described as an information
exchange that alters the behavior of the communicating animals. Acoustic
communication signals (typically vocalizations) are shaped by the physics
of the sound-producing organs, the physical media they traverse, and the
physics of the receptor organs (Bass and Clark, Chapter 2; Fitch and
Hauser, Chapter 3; Ryan and Kime, Chapter 5). Vocal communication
signals are also shaped by the perceptual mechanisms of the receiver, by
the proximate behavioral states of the senders and receivers (Boughman
and Moss, Chapter 4; Yamaguchi and Kelley, Chapter 6), and by the evolutionary history of the senders and receivers, most often in the context of
sexual selection. The information in vocal signals is represented by nonrandom acoustic variation that may either form discrete categories or fall
along graded continua. Likewise, vocal signals may be perceived as
members of discrete categories or along graded continua. Whether graded
or discrete, animals must account for the statistical variation in vocal signals
as they are produced, transmitted, and perceived. Ultimately, this means
that acoustic behaviors are constrained by the natural variation in communication signals.
The wide diversity of behavioral constraints makes exploration of the
neural mechanisms of acoustic communication both exciting and daunting.
On one hand, one of the grand challenges in neurobiology has been the
application of mechanistic analysis to perceptual and cognitive components
of brain function, and the neuroethology of acoustic communication provides a logical and rigorous approach to such problems. At the same time,
however, proper treatment of the mechanisms of acoustic communication
requires a neural analysis that is sensitive to multiple levels of biological
organization along with information-theoretic analyses that capture variations in behavior and signal acoustics. Despite good progress on many
324
7
The Neuroethology of
Vocal Communication:
Perception and Cognition
Timothy Q. Gentner and Daniel Margoliash
In its most common sense, acoustic communication occurs between animals,
but in special cases it may occur within individual animals in the context of
autocommunication. Communication can be described as an information
exchange that alters the behavior of the communicating animals. Acoustic
communication signals (typically vocalizations) are shaped by the physics
of the sound-producing organs, the physical media they traverse, and the
physics of the receptor organs (Bass and Clark, Chapter 2; Fitch and
Hauser, Chapter 3; Ryan and Kime, Chapter 5). Vocal communication
signals are also shaped by the perceptual mechanisms of the receiver, by
the proximate behavioral states of the senders and receivers (Boughman
and Moss, Chapter 4; Yamaguchi and Kelley, Chapter 6), and by the evolutionary history of the senders and receivers, most often in the context of
sexual selection. The information in vocal signals is represented by nonrandom acoustic variation that may either form discrete categories or fall
along graded continua. Likewise, vocal signals may be perceived as
members of discrete categories or along graded continua. Whether graded
or discrete, animals must account for the statistical variation in vocal signals
as they are produced, transmitted, and perceived. Ultimately, this means
that acoustic behaviors are constrained by the natural variation in communication signals.
The wide diversity of behavioral constraints makes exploration of the
neural mechanisms of acoustic communication both exciting and daunting.
On one hand, one of the grand challenges in neurobiology has been the
application of mechanistic analysis to perceptual and cognitive components
of brain function, and the neuroethology of acoustic communication provides a logical and rigorous approach to such problems. At the same time,
however, proper treatment of the mechanisms of acoustic communication
requires a neural analysis that is sensitive to multiple levels of biological
organization along with information-theoretic analyses that capture variations in behavior and signal acoustics. Despite good progress on many
324
7
The Neuroethology of
Vocal Communication:
Perception and Cognition
Timothy Q. Gentner and Daniel Margoliash