The Biology of Traditions: Models and Evidence. Dorothy M. Fragaszy and Susan Perry, eds. Cambridge University Press, Cambridge, United Kingdom, 2003. 474 pp., illus. $95.00 (ISBN 0521815975 cloth).
How do we identify animal traditions? Imagine two monkeys—white-faced capuchin monkeys—quietly playing a game. The game is played with apparent intensity and concentration, and always involves two participants. Despite the nature of the game, which frequently has one monkey prying its finger or hair out of the other monkey's mouth, participation is clearly voluntary, and apparently desirable. One monkey learns it from another, and group members have played it for 10 years. No other white-faced capuchin group plays this game. What is an ethologist to think?
This kind of question became the genesis of The Biology of Traditions: Models and Evidence. The editors, Dorothy Fragaszy and Susan Perry, were well aware of the assignment of “cultural” designations to some animal behaviors; they had a different agenda, one rooted in ethology and in Tinbergen's (1963) classic questions of causation, ontogeny, evolution, and survival value, which in turn were rooted in the activities of nonhuman animals. Resisting the temptation to coin new jargon, Fragaszy and Perry define traditions in an ethological context: “enduring behavior patterns shared among members of a group that depend to a measurable degree on social contributions to individual learning, resulting in shared practices among members of a group.”
Those who study animal traditions have set themselves a difficult task. What are researchers to make of group-specific behaviors? How can they distinguish a tradition from repeated innovation? What is the role of genetics in shared behaviors? These and other questions are difficult to answer in field settings, especially when directed at the long-lived, slow-developing animals that are most likely to have traditions. Every chapter in this book is thought-provoking because of the devotion to rigor that these authors bring to their work and because of the difficult questions they ask.
The chapters range across taxa (primates, birds, rats, and dolphins) and behaviors (vocalization, games, tool use, and more foraging modes than most of us can imagine). In so doing, they collectively address Tinbergen's questions, with examples ranging from suggestions that games involving the prying of fingers out of mouths (see above) might indeed have survival value to studies of brain size and social learning, and from the development of birdsong to the ontogeny of dolphins' foraging behavior. Unlike many edited volumes, The Biology of Traditions includes careful cross-referencing between chapters. Several chapters are rich with tables, offering a resource to be mined repeatedly for reports of possible traditions and tests of behavioral hypotheses. Although many chapters are organism centered, there is also a review of models of social learning, and an intriguing suggestion about the use of cue reliability to assess possible traditions. Likewise, although many chapters are devoted to field explorations, it is also clear that laboratory investigation offers great precision. As a fan of cockroach diversity and what it can tell us, I appreciate Bennett Galef's paean in chapter 6 to that great social learner, the Norway rat. It is not only the “charismatic megafauna” that are worthy of our attention; the not-so-charismatic fauna have news for us as well.
This brings us to chocolate. The story begins along the banks of the River Po, where members of some rat colonies dive into the water to feed on mollusks; members of other colonies never dive for food. Is this intriguing bimodal distribution of behavior in the field evidence for social learning? One might think so, but in the laboratory, Galef found that adult rats do not dive for food (chocolate), even if they observe that other rats do so. In contrast, about 20 percent of juvenile rats will dive to retrieve chocolate with or without exposure to other diving rats; in fact, if juvenile rats are taught to swim, almost all of them (90 percent) will spontaneously dive for food. The diving question may actually be one of swimming and, ultimately, food availability.
It is this little surprise, as well as countless others like it throughout the chapters, that makes this book a treasure. For that reason, I intend to use this book the next time I teach a graduate seminar in behavior. Although cetaceans and orangutans are a bit thin on the ground at the Midwestern campus where I teach, the questions that emerge from considering traditions in these and other animals encourage critical thinking. I only wish Cambridge University Press had invested in a species index; there are abundant examples throughout the book, and I would like to be able to access them efficiently.
The editors preface The Biology of Traditions with the statement that it is “intended for individuals interested in understanding social learning...from a biological perspective.” I believe they have overshot their mark in the best way possible. By inviting experts in the field to focus their best thoughts and experience on untangling some of the more difficult problems in behavioral ecology, and by encouraging those experts to contribute to a truly synthetic and integrated volume, Fragaszy and Perry have generated a book that is likely to reward any scientist—and certainly any behavioral scientist—interested in the nature of evidence and in relationships between appearance and reality.