The genetics of… leash-biting?: Genetics and the Social Behavior of the Dog, by John Paul Scott and John L. Fuller

University of Chicago Press, 1965 and 1998. $21.95 pbk (XVIII + 468 pages)ISBN 0 226 74338 1For 13 years, John Paul Scott and John Fuller operated a ‘school for dogs’ at the Jackson Laboratory in Bar Harbor, Maine. During that time, more than 500 animals passed through their kennels. The dogs were nurtured, observed and tested for the first 100 days after birth in an effort to understand how heredity influences the organization of mammalian social behavior. The project consisted of two major experiments. The first was a behavioral survey of five breeds. From this, Scott and Fuller formulated a working hypothesis that genetics defines discrete developmental stages, including ‘windows of opportunity’ when behavioral centers in the brain are forming. During these critical periods, behavioral centers are competent to respond to instructive environmental events, with lasting effects on the animal’s behavior. This view prompted the second major experiment – a set of mendelian crosses between two purebred lines to investigate innate differences. The results of Scott and Fuller’s work were reported in The Genetics and Social Behavior of the Dog, which first appeared in 1965 and has recently been re-released. Since its first printing, the book has taken on an almost biblical importance to dog breeders and fanciers. Although the book has some redeeming qualities, generally it falls short of its lofty reputation.The book suffers from poor organization and, at times, from loose scientific reasoning. Because the authors tried to appeal to too broad an audience, the reader is constantly switching gears between quantitative analyses and anecdotal observations. This lack of continuity unfortunately obscures a worthwhile experimental perspective – that behavioral ontogeny is genetically rooted, and that most modifications involve raising or lowering release thresholds.Especially disheartening (to geneticists and evolutionary biologists) is the set of behaviors chosen for study. Dog breeds have been established, at least partially, through selection for robust action patterns such as pointing, retrieving and herding. It follows that the genetic architecture of these traits is relatively simple, as is typically the case with artificially selected traits (e.g. in maize). Moreover, breed-specific patterns have a narrow norm of reaction and show low variance in purebred populations, making them particularly well suited for genetic dissection. Yet Scott and Fuller chose instead to focus on emotionality, temperament and performance aptitudes, staying true to their backgrounds in human psychology. Many of their behavioral assays, which were presumably meant to reflect ‘personality’ traits, were not placed in enough of a context for the reader to fully appreciate (e.g. leash biting, balking at stairs and so on). As a consequence, interest wanes over the course of the book.The book does, however, document some intriguing findings. For instance, the difference in ‘barkfullness’ between two breeds was consistent with a single gene model, and differences in both the seasonality and frequency of estrus were, most likely, due to a small number of genes. Because of the project’s long duration, some important generalizations could also be stated, the most notable of which was the existence of a critical period for socialization in dogs. This finding was significant because it extended the concept of imprinting (described in birds by Konrad Lorenz 25 years earlier) to mammals. Although Scott and Fuller’s data fall short of actually demarcating this temporal window, the data for the period’s existence are nonetheless compelling. Unfortunately, there is no discussion of possible breed differences in the timing or threshold of socialization that could allow genetic analysis. The authors also do not discuss the possible importance of hereditary differences in socialization between the domestic dog and its wild progenitor, the wolf. Was expansion of the socialization window through mutation a major step in the domestication of dogs?Perhaps the most rewarding aspect of the book is its ambience. Genetics and the Social Behavior of the Dog provides a lot of opportunities to ponder the basis of behavior, and in so doing takes us back to a scientific climate very different from the present. The gap has widened between biology and nature in the last 35 years, and funding competitiveness further restricts long-term projects and experimental risk-taking. So although Scott and Fuller’s 13-year project might not have lived up to expectations, we think young biologists will admire the authors’ audacity and be envious of their opportunity.