Robert Trivers

American evolutionary biologist and sociobiologist

Robert L. Trivers (born 19 February 1943) is an American evolutionary biologist and sociobiologist, most noted for proposing the theories of reciprocal altruism (1971), parental investment (1972), and parent-offspring conflict (1974).


  • People are often unconscious of some of the mechanisms that naturally occur in them in a biased way. For example, if I do something that is beneficial to you or to others, I will use the active voice: I did this, I did that, then benefits rained down on you. But if I did something that harmed others, I unconsciously switch to a passive voice: this happened, then that happened, then unfortunately you suffered these costs. One example I always loved was a man in San Francisco who ran into a telephone pole with his car, and he described it to the police as, "the pole was approaching my car, I attempted to swerve out-of-the-way, when it struck me."
    Let me give you another, the way in which group membership can entrain language-usages that are self-deceptive. You can divide people into in-groups or out-groups, or use naturally occurring in-groups and out-groups, and if someone's a member of your in-group and they do something nice, you give a general description of it – "he's a generous person". If they do something negative, you state a particular fact: "in this case he misled me", or something like that. But it's exactly the other way around for an out-group member. If an out-group member does something nice, you give a specific description of it: "she gave me directions to where I wanted to go". But if she does something negative, you say, "she's a selfish person". So these kinds of manipulations of reality are occurring largely unconsciously.
    • As quoted in Science at the Edge: Conversations with the Leading Scientific Thinkers of Today (2008), p. 170
  • Darwinian social theory gives us a glimpse of an underlying symmetry and logic in social relationships which, when more fully comprehended by ourselves, should revitalize our political understanding and provide the intellectual support for a science and medicine of psychology. In the process it should also give us a deeper understanding of the many roots of our suffering.
    • Foreword to The Selfish Gene by Richard Dawkins (1976)

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