The Dynamic Dance: Nonvocal Communication in African Great Apes

  • Barbara J. King
Harvard University Press: 2004. 240 pp. $29.95, £19.95, €27.70 0674015150 | ISBN: 0-674-01515-0

The idea that certain primate vocalizations are information-bearing signals is an old one. In 1892, R. L. Garner used playbacks of monkey vocalizations to deduce that some monkey calls had referential significance — they were what we now know as food or alarm calls. But it was much later, only about fifty years ago, that the concepts of ‘information’ and ‘signal’ became clear enough to be formalized mathematically by Norbert Wiener and Claude Shannon, giving birth to modern information theory.

The kiss: chimpanzee communication is based on interactions, according to dynamic systems theory. (Photographs courtesy of Frans de Waal.)

By isolating and formally defining a quantity termed information, which has surprising affinities to the physicists' concept of entropy, Shannon and Wiener planted the seeds of today's digital world, where diverse types of information can be transformed, stored or transmitted as a pattern of binary digits (or ‘bits’, a term they introduced). Shannon and Wiener were acutely aware that information (a measurable quantity of signals) is not to be confused with meaning (which depends on context and interpretation, and exists in the eye of the beholder). They both explicitly set aside ‘meaning’ as a topic for future work, and it remains formally undefined today.

Because meaning, rather than information, is central to animal communication, information theory plays a less prominent role in contemporary ethology than in telecommunications research or neuroscience. Indeed, there is a growing tendency among some primatologists to reject information theory entirely, and Barbara King's book The Dynamic Dance is a forceful example of this trend.

King is an anthropologist who has spent years observing captive chimpanzees, bonobos and gorillas. The first 85 pages of this book argue that the ‘signaller–receiver’ model of animal communication (King calls it the Shannon/Marler framework, acknowledging the influence of ethologist Peter Marler) must be supplanted by King's new approach, dynamic systems theory. Dynamic-systems theorists eschew quantitative data, reject the notion that animal signals contain information, and focus instead on interactive aspects of ape social behaviour (their “dynamic dance”).

The core insight in King's book is that communicative exchanges among apes are ‘co-regulated’: interactions unfold contingently and unpredictably. King is certainly correct that ape communication systems (like those of many other animals) are complex and contingent. Far from being simple robotic automata that respond to a particular signal in a fixed and pre-programmed fashion, apes show considerable social intelligence, interpreting each other's actions against a backdrop of their history and current social context, and responding appropriately. But this is also true of two dogs interacting, as is quickly apparent to even casual observers.

Recognition of contingency and context in communication provides a rationale not for rejecting information theory, but for extending it, as its founders recognized. Information theory rigorously specifies a quantitative upper bound to the information borne in signals versus that supplied by receivers — surely a useful tool for understanding how receivers interpret and respond to communicative behaviour. I have rarely seen the baby–bathwater distinction so consistently elided as in this book.

The second part of the book features detailed descriptions of ape behavioural interactions, many based on King's own observations. King studiously avoids any interpretations of ape intentionality. Furthermore, because she rejects quantitative data (which she believes obscure the underlying co-regulatory nature of communication), we are given no summaries or statistics. Unfortunately, these two theoretical convictions conspire to make this section rather heavy going.

Space precludes quoting these descriptions in full, but here is a short excerpt of four from a sequence of nineteen behaviours: “Elikya watches Tamuli eat, then pulls on Tamuli's hand... As Tamuli chews, Elikya attempts to take a bit of orange but Tamuli turns her head away. Elikya again tries to take a bit of Tamuli's chewed orange but Tamuli pulls her head back; Elikya climbs off Tamuli and goes back to her mother.” The middle 100 pages of the book are full of such “qualitative data”. Although King is undoubtedly a sensitive observer of ape interactions, she rarely shares her interpretations of these sequences with the reader, and these descriptions are presented primarily as demonstrations of the co-regulated nature of ape interactions. Although the cover describes the book as “eye opening”, I personally found these long and detailed descriptions of ape interactions made excellent bedtime reading.

In conclusion, like most clarion calls to scientific revolution, this book both oversimplifies the opposing viewpoint and overstates the significance and novelty of its own stance. King is correct that information theory should be extended to incorporate context and meaning, but this point was noted by the theory's founders and is widely recognized today. The reader seeking an alternative in ‘dynamic systems theory’, as presented in this book, will find little more than a promissory note, and would probably be better served by spending a day at the zoo watching ape social behaviour themselves.