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Synopsis: The Social Gene

Kin selection has been accepted for half a century by most evolutionists and animal behaviorists as a mechanism that allows altruism and herd formation only among close relatives and is considered an extension of Darwinian evolution. This book disputes the claim for social vertebrates on the grounds that it does not adequately describe animal behavior in the field, and replaces it instead with a hypothesis of animal rewards.


  1. Introduction
  2. Sociality of Ungulates
  3. Sociality of Carnivores
  4. Sociality of Primates
  5. Inclusive Fitness
  6. The Social Gene
  7. Reciprocity
  8. Hormonal Control of Sociality
  9. The Nursery
  10. Rite of Passage
  11. Homosexuality and Sociality
  12. Darwinian and non-Darwinian Societies

Chapters 2, 3 and 4 discuss the field evidence in three major orders of mammals that animals may form colonies or herds which include unrelated animals and that some among the latter may assist others at a cost to themselves, thereby disproving the basic tenets of kin selection.  

Chapter 5 presents the case that animals do not have the capacity to direct their goals towards maximizing their fitness by benefitting collateral relatives.

Chapter 6 is the crux of the book. It presents the argument that animals seek to maximize their rewards rather than their fitness and demonstrates that proximity to another social animal is a reward in its own right for both participants. This allows animals to parlay proximity for other tangible rewards. The genes allocate those rewards in order to optimize individual fitness.

Chapter 7 discusses an alternative mechanism that has been proposed to account for animal interactions, called reciprocal altruism, and shows that it is compatible with social genes, but is more restrictive than necessary.

Chapter 8 introduces the evidence that the direction which social rewards take to each gender is controlled by gonadal hormones which accounts for the sexual segregation observed in many species outside the mating season.

Chapters 9 and 10 discuss the relationship between parents and their young. These chapters address infant imprinting and explain why adoption of infants occurs among animals and humans; they present a new mechanism for dispersal by young adults.

Chapter 11 extends the social gene hypothesis to give an explanation for human homosexuality based on hormonal influences on sociality that complements the discussion in chapter 8.

Chapter 12 divides animal and human societies into two categories depending on whether they are consistent with the Darwinian maxim that the fittest (in the sense of most genetically precocious) are the ones most likely to survive; it proposes that societies that do not fulfil that dictum are intrinsically unstable.