The Many Roots Of Our Suffering - Reflections )n Robert Trivers (1943–2026)

In March 2026, three prominent thinkers died within a day of each other. Lavish obituaries immediately marked the deaths of the always-wrong environmentalist Paul Ehrlich and the often-obscure political philosopher Jürgen Habermas. But two weeks after the death of Robert Trivers, one of the greatest evolutionary biologists since Charles Darwin, not a single major news source has noticed his passing. This despite Trivers’s singular accomplishment of showing how the endlessly fascinating complexities of human relations are grounded in the wellsprings of complex life. And despite the fact that the man’s life was itself an object of fascination. Trivers was no ordinary academic. He was privileged in upbringing but louche in lifestyle, personally endearing but at times obstreperous and irresponsible, otherworldly brilliant but forehead-slappingly foolish. 

Trivers’s contributions belong in the special category of ideas that are obvious once they are explained, yet eluded great minds for ages; simple enough to be stated in a few words, yet with implications that have busied scientists for decades. In an astonishing creative burst from 1971 to 1975, Trivers wrote five seminal essays that invoked patterns of genetic overlap to explain each of the major human relationships: male with female, parent with child, sibling with sibling, partner with partner, and a person with himself or herself. 

The fallout for science was vast. The fields of sociobiology, evolutionary psychology, behavioural ecology, and Darwinian social science are largely projects that test Trivers’s hypotheses. The ideas took pride of place in E. O. Wilson’s Sociobiology in 1975, Richard Dawkins’s The Selfish Gene in 1976, and many other bestsellers in the next three decades such as Robert Wright’s The Moral Animal (1994) and my own How the Mind Works (1997) and The Blank Slate (2002). In 2007 the ideas earned Trivers the Crafoord Prize, the equivalent of a Nobel for fields not recognised by Nobels.

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In another landmark, Trivers turned to relations among people who are not bound by blood. No one doubts that humans, more than any other species, make sacrifices for nonrelatives. But Trivers recoiled from the romantic notion that people are by nature indiscriminately communal and generous. It’s not true to life, nor is it expected: in evolution as in baseball, nice guys finish last. Instead, he noted, nature provides opportunities for a more discerning form of altruism in the positive-sum exchange of benefits. One animal can help another by grooming, feeding, protecting, or backing him, and is helped in turn when the needs reverse. Everybody wins. 

Trivers called it reciprocal altruism, and noted that it can evolve only in a narrow envelope of circumstances. That is because it is vulnerable to cheaters who accept favours without returning them. The altruistic parties must recognise each other, interact repeatedly, be in a position to confer a large benefit on others at a small cost to themselves, keep a memory for favours offered or denied, and be impelled to reciprocate accordingly. Reciprocal altruism can evolve because cooperators do better than hermits or misanthropes. They enjoy the gains of trading surpluses of food, pulling ticks out of one another’s hair, saving each other from drowning or starvation, and babysitting each other’s children. Reciprocators can also do better over the long run than the cheaters who take favours without returning them, because the reciprocators will come to recognise the cheaters and shun or punish them. 

All this was quickly snapped up by game theorists, economists, and political scientists. But in a less-noticed passage, Trivers pointed out its implications for psychology. Reciprocal altruists must be equipped with cognitive faculties to recognise and remember individuals and what they have done. That helps explain why the most social species is also the smartest one; human intelligence evolved to deal with people, not just predators and tools. They also must be equipped with moral emotions that implement the tit-for-tat strategy necessary to stabilise cooperation. Sympathy and trust prompt people to extend the first favour. Gratitude and loyalty prompt them to repay favours. Guilt and shame deter them from hurting or failing to repay others. Anger and contempt prompt them to avoid or punish cheaters. 

And in a passage that even fewer readers noticed, Trivers anticipated a major phenomenon later studied in the guise of “partner choice.” Though it pays both sides in a reciprocal partnership to trade favours as long as each one gains more than he loses, people differ in how much advantage they’ll try to squeeze out of an exchange while leaving it just profitable enough for the partner that he won’t walk away. That’s why not everyone evolves into a rapacious scalper: potential partners can shun them, preferring to deal with someone who offers more generous terms.

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And since humans are language users—indeed, reciprocity may be a big reason language evolved—any tendency of an individual to reciprocate or cheat, lavish or stint, does not have to be witnessed firsthand but can be passed through the grapevine. This leads to an interest in the reputation of others, and a concern with one’s own reputation. 

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But Trivers rapidly spotted what everyone else missed, and still misses, together with the less biologically obvious concept of self-deception, so there must be another piece to the puzzle. During his junior year at Harvard, Trivers suffered two weeks of mania and then a breakdown that hospitalised him for two months. Bipolar disorder afflicted him throughout his life. I can’t help but wonder whether Trivers’s fecund period was driven by episodes of hypomania, when ideas surge and insights suddenly emerge through clouds of bafflement. Gamers sometimes “overclock” their computers, running the CPU at a higher speed than the rated limit, which boosts performance but risks instability and crashes. Did Trivers experience bursts of overclocking in the early 1970s? It would explain another fact about the man that was obvious to anyone who met him later: Trivers reeked of marijuana. His heavy use may have had a source other than his Jamaicaphilia. One wonders whether Trivers was self-medicating, with long-term costs to his clock speed. 

- Steven Pinker