In my undergraduate course on animal behavior, the topic that without fail generates the most interest, discussion, and often humor is—perhaps unsurprisingly—mate choice. The next most attention-grabbing topic is altruism (for the moment, read as goodness). I believe that altruism ranks so highly on the interest scale, so to speak, because it is one concept in animal behavior that people can intuitively understand and integrate conceptually into virtually every aspect of their lives: their interactions with others, their political and social institutions, and their religious beliefs. Have we not all wondered for whom or under what conditions we would be willing to sacrifice ourselves?
Altruism is a relatively simple concept to define. It refers to behavior that increases the fitness of the recipient at a cost to the fitness of the donor. When one individual comes to the aid of, or provides resources to, another individual, altruism has taken place, at least in theory. Altruism is a much more complex concept than this simple definition implies, however. The complexity lies in defining a currency of fitness that can be consistently applied in studies of different kinds of organisms. The most commonly used currency of fitness is reproductive success; thus, an altruistic act is one that increases the reproductive success of a recipient at a cost to the reproductive success of the donor. But in fact, most real or apparent altruistic acts occur in a context completely independent of reproduction, or toward individuals that are past their reproductive age. The theory can be modified to account for such acts—for example, “reciprocal altruism” holds that individuals help others deemed likely to reciprocate the help—but any measure of fitness will run into difficulty when it comes to making general and specific testable predictions. A second problem is that empirically, it is often impossible to accurately quantify the costs (to the donor) of particular behavioral acts. Whether the aid given consists of protection, food, or any other service or resource, the cost the donor incurs is often only theoretical. Can a theory be rigorously tested if the individual variables cannot be quantified?
Despite these difficulties, altruism does occur in both humans and other animal species, even if it is sometimes hard to study quantitatively. Although altruism was once thought to be one of those behavioral traits, like tool making and complex language, that separate humans from other species, we now know that we are not so different from other species. Altruism in humans, however, is clearly complicated by cultural evolution—it is no simple matter to disentangle the interaction between biology and culture.
This anthropocentric view of altruism is clearly evident in the history of altruism as an idea, a history that Lee Alan Dugatkin brings to life in The Altruism Equation: Seven Scientists Search for the Origins of Goodness. In this delightful book, Dugatkin takes the reader from Darwin's confusion over honeybee behavior (and his fear that sterile worker bees raising siblings represented an exception to natural selection) through more than 125 years of research, theoretical thinking, and public argument about what altruism or goodness is, its relationship to kinship, and how it has been studied.
Dugatkin focuses his historical attention on seven men who were, in his opinion, the most important biologists in the development of the current theory of altruism and of empirical tests of that theory. Those biologists are Charles Darwin, Petr Kropotkin, Thomas H. Huxley, J. B. S. Haldane, W. C. Allee, William D. Hamilton, and George Price. Anyone compiling such a list might choose different members, but there is no doubt that these scientists played a central role in our current understanding of altruism. Of course, those on the list did not work alone, and Dugatkin also discusses the contributions, direct or indirect, made by at least eight other biologists (Ronald Fisher, Sewall Wright, Richard Dawkins, John Maynard Smith, E. O. Wilson, Steve Emlen, Paul Sherman, and Hudson Kern Reeve), sometimes in such great detail that I wasn't always sure who was on the central list of seven to which the book's title refers.
The history of altruism was not a steady, steplike process. After Darwin highlighted the apparent difficulty that altruism in social insects presented for his theory of natural selection as an agent of evolutionary change, biologists did not immediately begin thinking about a general theory of altruism (or, for that matter, evolution). That development would wait more than 75 years. Following Darwin, Kropotkin and Huxley waged academic battles over whether altruistic acts were dependent on the relatedness of individuals. The answer, of course, is both yes and no, depending on the ecological and behavioral circumstances.
A general theory of altruism would not surface until the early 1960s, when Bill Hamilton published what has become known as “Hamilton's rule”—that is, altruism (or helping or aid-giving behavior) can evolve whenever the benefits of the act devalued (multiplied) by the coefficient of relatedness between the individuals exceeds the cost of the act. The simplicity of the final theory belies the underlying complex mathematics that led to it, as well as the long history of thinking about these ideas. Although the impacts of Hamilton's theory were not immediate, they were dramatic. Once the model was widely understood, it had impacts well beyond considerations of altruism. It led at least in part, if not directly, to a gene perspective of evolution, the theory of kin selection, the foundation for much of the emerging field of sociobiology, and sex ratio theory; it also led to the development of game theory and the notion of evolutionary stable strategies. In other words, it changed the way people thought about social behavior specifically, as well as about evolution generally.
As fascinating as the intellectual development of altruism theory is, the personal, human side of the development is equally interesting. As I read the historical account, I thought that Dugatkin had done for social behavior what James Watson did for the discovery of the structure of DNA with The Double Helix. Scientists whom most people know simply as the authors of citations in a publication are brought to life in this book, and their interactions, collaborations, and sometimes ill feelings toward one another make for an intriguing story. Although I think that Bill Hamilton is clearly the central figure in the history of altruism as an evolutionary concept, as Dugatkin portrays him, all of the biologists discussed in this book made valuable contributions, and Dugatkin does an excellent job of putting everyone's historical and current roles in perspective.
I thoroughly enjoyed reading this book, and I think anyone with an interest in animal behavior will find it valuable, but I did find myself wishing from time to time that the author had included more information about some topics. Specifically, I think a longer discussion is warranted on the semantic issues concerning altruistic as opposed to cooperative behavior. I would also have enjoyed more discussion of the interaction between culture and biology in shaping altruism in humans. Given the focus at the end of the book on presenting the results of specific research projects, it would have been helpful to see a discussion of the practical difficulties of testing the underlying theory, the simplicity of Hamilton's ideas notwithstanding. Last, I think the book ended on a flat note, with no discussion of where the study of altruism is headed. Surely not everything regarding altruism has been solved; indeed, some people still argue about whether it occurs at all. Although thanks to this book we can better understand the history of the ideas, some predictions or even speculations about future work would have allowed the author to end on an altruistic note.