David Wilson

The substance of the commentaries, however, reveals considerable disagreement about how UO conceptualizes the idea of group selection. Dennett describes the issues as “mind-twistingly elusive and slippery” and hints that it is mere hype to say that group selection has been revived. Barrett and Godfrey-Smith discuss the problem of multiple perspectives at length and claim that we are too liberal in our definition of groups. We believe that these criticisms obscure the simplicity of the basic question that group selection theory is designed to answer and the historical continuity of that theory, from Darwin to the present.

Many evolutionary models assume that behaviors are caused directly by genes. An implication is that behavioral uniformity should be found only in groups that are genetically uniform. Yet, the members of human social groups often behave in a uniform fashion, despite the fact that they are genetically diverse. Behavioral uniformity can occur through a variety of psychological mechanisms and social processes, such as imitation, consensus decision making, or the imposition of social norms. We present a series of models in which genes code for social transmission rules, which in turn govern the behaviors that are adopted. Transmission rules can evolve in randomly formed groups that concentrate phenotypic variation at the between-group level, favoring the evolution of altruistic behaviors and other group-advantageous traits. In addition, a direct bias toward adopting altruistic behaviors can evolve. Our models begin to show how group selection can be a strong force in human evolution, despite the absence of extreme genetic variation among groups

The substance of the commentaries, however, reveals considerable disagreement about how UO conceptualizes the idea of group selection. Dennett describes the issues as “mind-twistingly elusive and slippery” and hints that it is mere hype to say that group selection has been revived. Barrett and Godfrey-Smith discuss the problem of multiple perspectives at length and claim that we are too liberal in our definition of groups. We believe that these criticisms obscure the simplicity of the basic question that group selection theory is designed to answer and the historical continuity of that theory, from Darwin to the present.

It is a challenge to explain how evolutionary altruism can evolve by the process of natural selection, since altruists in a group will be less fit than the selfish individuals in the same group who receive benefits but do not make donations of their own. Darwin proposed a theory of group selection to solve this puzzle. Very simply, even though altruists are less fit than selfish individuals within any single group, groups of altruists are more fit than groups of selfish individuals. If a population is subdivided into many groups that vary in their altruistic tendencies, altruism will be favored at the level of selection among groups even as it is being disfavored at the level of selection among individuals within groups. Darwin’s scenario became the basis for a theoretical framework called multilevel selection theory.

Evolutionary science (ES) and contextual behavioral science (CBS) have developed largely independently during the last half century. However, the earlier histories of these two bodies of knowledge are thoroughly entwined. ES provides a unifying theoretical framework for the biological sciences, and is increasingly being applied to human-related sciences. Meanwhile, CBS is concerned with influencing human behavior in a practical sense. This groundbreaking volume seeks to integrate ES and CBS to promote real, positive change in peoples' lives. Evolution and Contextual Behavioral Science offers a unique glimpse into the histories of ES and CBS, shows how they are intrinsically linked, and outlines why their integration--or, reunification--is essential. By examining these two schools of thought side by side, you'll gain an understanding of why functional and contextual approaches in CBS need to be combined with ES for both fields to advance more rapidly. Finally, rather than the sequential relationship that is typically imagined between ES and CBS, you'll discover how an integrated relationship between these two sciences will result in a better framework for understanding predicting, and influencing human behavior--back cover.

_A powerful treatise that demonstrates the existence of altruism in nature, with surprising implications for human society_ Does altruism exist? Or is human nature entirely selfish? In this eloquent and accessible book, famed biologist David Sloan Wilson provides new answers to this age-old question based on the latest developments in evolutionary science. From an evolutionary viewpoint, Wilson argues, altruism is inextricably linked to the functional organization of groups. “Groups that work” undeniably exist in nature and human society, although special conditions are required for their evolution. Humans are one of the most groupish species on earth, in some ways comparable to social insect colonies and multi-cellular organisms. The case that altruism evolves in all social species is surprisingly simple to make. Yet the implications for human society are far from obvious. Some of the most venerable criteria for defining altruism aren’t worth caring much about, any more than we care much whether we are paid by cash or check. Altruism defined in terms of thoughts and feelings is notably absent from religion, even though altruism defined in terms of action is notably present. The economic case for selfishness can be decisively rejected. The quality of everyday life depends critically on people who overtly care about the welfare of others. Yet, like any other adaptation, altruism can have pathological manifestations. Wilson concludes by showing how a social theory that goes beyond altruism by focusing on group function can help to improve the human condition.

_A powerful treatise that demonstrates the existence of altruism in nature, with surprising implications for human society_ Does altruism exist? Or is human nature entirely selfish? In this eloquent and accessible book, famed biologist David Sloan Wilson provides new answers to this age-old question based on the latest developments in evolutionary science. From an evolutionary viewpoint, Wilson argues, altruism is inextricably linked to the functional organization of groups. “Groups that work” undeniably exist in nature and human society, although special conditions are required for their evolution. Humans are one of the most groupish species on earth, in some ways comparable to social insect colonies and multi-cellular organisms. The case that altruism evolves in all social species is surprisingly simple to make. Yet the implications for human society are far from obvious. Some of the most venerable criteria for defining altruism aren’t worth caring much about, any more than we care much whether we are paid by cash or check. Altruism defined in terms of thoughts and feelings is notably absent from religion, even though altruism defined in terms of action is notably present. The economic case for selfishness can be decisively rejected. The quality of everyday life depends critically on people who overtly care about the welfare of others. Yet, like any other adaptation, altruism can have pathological manifestations. Wilson concludes by showing how a social theory that goes beyond altruism by focusing on group function can help to improve the human condition.

The hypothesis of group selection fell victim to a seemingly devastating critique in 1960s evolutionary biology. In Unto Others, we argue to the contrary, that group selection is a conceptually coherent and empirically well documented cause of evolution. We suggest, in addition, that it has been especially important in human evolution. In the second part of Unto Others, we consider the issue of psychological egoism and altruism -- do human beings have ultimate motives concerning the well-being of others? We argue that previous psychological and philosophical work on this question has been inconclusive. We propose an evolutionary argument for the claim that human beings have altruistic ultimate motives.

We address the following issues raised by the commentators of our target article and book: the problem of multiple perspectives; how to define group selection; distinguishing between the concepts of altruism and organism; genetic versus cultural group selection; the dark side of group selection; the relationship between psychological and evolutionary altruism; the question of whether the psychological questions can be answered; psychological experiments. We thank the contributors for their commentaries, which provide a diverse agenda for future study of evolution and morality. Our response will follow the organization of our book, distinguishing between evolutionary issues that concern fitness effects and psychological issues that concern motives.