Evolution of Animal Communication: Reliability and Deception in Signaling Systems, The

Integrative and Comparative Biology, Oct 2006 by MacDougall-Shackleton, Scott A

The Evolution of Animal Communication: Reliability and Deception in Signaling Systems. William A. Searcy and S. Nowicki

Princeton, NJ: Princeton University Press, 2005. 288 pp. ISBN 0-691-07095-4.

Are communicating animals straight-talkers or conmen? That is, when a gazelle slots, a songbird sings, or a mantis shrimp displays its weapons, are they sending a truthful signal to the receiver or trying to pull a fast one? The answer, like answers to most questions in biology, is that it depends. And it is how it depends that is the topic of Searcy and Nowicki's excellent treatise on animal communication. This book continues the eminent Monographs in Behaviour and Ecology series in fine form.

Over the years the pendulum has swung back and forth between views of animals as honest advertisers or deceitful manipulators, and the debates have sometimes been heated and polemic. For example, the concept of information content in a signal has swung from defining communication to being regarded as unnecessary for the study of communication. Searcy and Nowicki do a great job of both reviewing the history of these debates and in many cases providing reconciliation. One perennially controversial issue is whether song dialect regions in songbirds serve as indicators of genetic differences and could potentially lead to local adaptations. The authors review these studies well, pointing out how some debates have been essentially beside the point (patterns of genetic change, timing of song learning), and how other problems are more critical for the local adaptation hypothesis (lack of evidence for local adaptation, limited female dispersal). In this and other topics the authors do exactly what a good synthesis should: review the current data and provide future direction.

I found the balanced presentation by Searcy and Nowicki refreshing. That is not to say that the authors do not push their own viewpoints, but that they do so in a relatively evenhanded manner. Their overall conclusion is that signals usually are more or less honest, but that a certain amount of deception can, and often does, exist in signaling systems. Perhaps because I am Canadian I found this middle-road and moderate viewpoint refreshing.

The theoretical framework of this book follows the argument that senders should be selected to produce signals only if that benefits them (in terms of fitness), and receivers should respond to signals only if that benefits them. This selection acting both on senders to manipulate receivers and on receivers to scrutinize senders should result in signals, on average, containing reliable information. The balance between honesty and deception will depend upon a variety of factors including the degree of shared interest between signalers and receivers. The majority of the book is organized around 3 such situations: when interests overlap (for example, food begging by dependent young), when interests diverge (for example, courtship signals), and when interests oppose (for example, aggressive displays). Following this, communication networks in which eavesdroppers may make use of information directed to another receiver are considered. In each of these sections a variety of examples are used to illustrate variations on the main theme.

The writing in this book is delightfully clear. In particular, mathematical models (of which the field of communication has attracted a great number) are explained clearly enough for the computationally challenged to follow. The figures are clear and well selected, and the production quality is excellent. One might consider the selection of examples to be taxonomically biased, but my view is that the overrepresentation of some examples, such as birds, is a direct reflection of their most-favored status as study subjects in behavioral ecology. Perhaps nonornithologists can take some solace in the fact that the book does not exclusively use data from birds because it probably could have.

A book is rather successful when a reader's only critique is of the title. Searcy and Nowicki's Evolution of Animal Communication is not a comprehensive treatise on the topic, and it was not meant to be. I would have suggested reversing the title and subtitle. Although this is not an omnibus review, it is an outstanding synthesis on "Reliability and Deception." This excellent monograph should be required reading for anyone in the field of animal communication.

Scott A. MacDougall-Shackleton

Departments of Psychology and Biology

University of Western Ontario

Advance Access publication August 11, 2006

doi:10.1093/icb/icl027