Reciprocity before Trivers

“New” ideas are rarely new. In science we stand on the shoulders of giants and whenever I read the works of the giants, I often find that many ideas or discoveries– that I thought were “mine” or belonged to some more recent author– were actually first described by Darwin or some other author from long ago.

I hope to soon publish a paper on a hypothesis I call “social bet-hedging” which is the idea that individuals might face a trade-off between investing in the quantity versus quality (strength) of cooperative relationships, and that, in unpredictable social environments having more friendships might be better than  investing in fewer stronger friendships (even if the opposite is true normally). More on this in a future blogpost.

Before publishing it, I looked through the cooperation literature and emailed people who have most influenced me on the topic of cooperative relationships: Ronald Noe, Dorothy Cheney, and Robert Seyfarth. I wanted to make sure that I had not accidentally stolen the idea from someone else.

If you read the scientific literature on a given topic in backwards chronological order, you find that authors with new ideas tend to overemphasize their originality. This is probably also true for novel technology. In science, most “new ideas” are really incremental developments or novel applications of older ideas. Work that is labeled “transformative” and “revolutionary” often involves taking something that’s been around awhile (but never fully appreciated) and showing its general importance in a convincing manner.

Even when new ideas are truly new, they often are built on a foundation that allows contemporary thinks to converge of the same new idea. For example, before Darwin famously discovered natural selection, some forester you probably never heard of named Patrick Matthew discovered it three decades earlier. He compared artificial selection on trees with what normally happens in a forest: the healthiest most fecund trees survive and reproduce (kinda obvious really). He wrote,

“There is a law universal in nature, tending to render every reproductive being the best possibly suited to its condition that its kind, or that organized matter, is susceptible of, which appears intended to model the physical and mental or instinctive powers, to their highest perfection, and to continue them so. This law sustains the lion in his strength, the hare in her swiftness, and the fox in his wiles. As Nature, in all her modifications of life, has a power of increase far beyond what is needed to supply the place of what falls by Time’s decay, those individuals who possess not the requisite strength, swiftness, hardihood, or cunning, fall prematurely without reproducing—either a prey to their natural devourers, or sinking under disease, generally induced by want of nourishment, their place being occupied by the more perfect of their own kind, who are pressing on the means of subsistence.”

That first sentence is not the best example of clear writing, but that was the style back then in ye olde days. Even more unfortunate is that he published this in an appendix to a book entitled Naval Timber and Arboriculture (1831) where it remained mostly unread.

As Ernst Mayr summarized:

Patrick Matthew undoubtedly had the right idea, just like Darwin did on September 28, 1838, but he did not devote the next twenty years to converting it into a cogent theory of evolution. As a result it had no impact whatsoever.

Not everyone thinks this is fair. Yep, there’s a full conspiracy theory regarding this “greatest cover-up in the history of science”.

The double invention of calculus is another example of new ideas coming about independently but simultaneously, giving the impression that the time was ripe and the stage was set.

New ideas never jump into existence fully formed by single people. They are memes that persist by being passed along (like natural selection), and they evolve by branching off from previous forms (like speciation). For this reason, most discoveries come into focus gradually. True “Eureka” moments in science are rare. Profound new idea are always built on foundation of less appreciated past work.

I was reminded of this recently while reading a section of the classic work Adaptation and Natural Selection by GC Williams (1966). So many of the ideas I attributed to Trivers’s notion of “reciprocal altruism” (1971) and its application to human friendship could be traced back to older works, even well-read classics like this one.

Before I present the key text, I’ll recap a bit of brief background. The concept of reciprocal altruism or reciprocity was formulated by Trivers 1971 (Quarterly Review of Biology) with the suggestion that each individual’s need to enforce mutual benefit could help explain many behaviors that underlie enduring cooperative relationships, including human friendship. The idea was extremely influential.

Trivers’ paper also touched upon on almost every related topic, such that for every subsequent extension of Trivers’ idea, one can find a mention of it in his original paper. For instance, biological market theory (Noe and Hammerstein 1994, 1995) later added the role of market effects and the emphasized a distinction between models of partner choice and partner control (i.e. reciprocal altruism). But in his paper, Trivers’ mentioned the role partner choice in friendship. He also described cases where cooperation was enforced by ecological circumstance rather than by behavior (now called “pseudoreciprocity” or “byproduct benefits”). He described applications to cleaner-client fish, which later became an important model system. Trivers also mentioned the iterated prisoner’s dilemma as a model for the evolution of reciprocity, which was later formalized by Axelrod & Hamilton ten years later (1981 Science). He even mentioned interactions between reciprocity and kinship which have only been experimentally explored recently. Although Trivers never actually worked on reciprocity himself, he at least mentioned almost all the new ideas and directions that would be developed from his theory.

As a term, “reciprocal altruism” is competing with other terms and concepts in the struggle for existence. In biology, the popularity of this term (and the breadth of its definition) rose to a peak in the 1990s, where it became mired in confusion and controversy, eventually falling in popularity until today it is defined very specifically and often considered unimportant outside of humans. I wrote a review explaining how and why this happened.

But I digress. My point here is that the foundations for the concept of reciprocity had already been floating around in the collective scientific consciousness before Trivers (1971). For example, the “tit-for-tat” demonstration built upon the ‘folk theorem’ of game theory–that repeating interactions which influence fitness can stabilize the evolution of almost any behavioral trait through social reward/punishment–an observation that has been understood since the 1950s.

A second example: here is the text from GC Williams Adaptation and Natural Selection: A Critique of Some Current Evolutionary Thought (1966) discussing contingency in cooperative relationships (bold emphasis mine).

…I wish to consider an apparent exception to the rule that the natural selection of individuals cannot produce group-related adaptations. This exception may be found in animals that live in stable social groups and have the intelligence and other mental qualities necessary to form a system of personal friendships and animosities that transcend the limits of family relationship. Human society would be impossible without the ability of each of us to know, individually, a variety of neighbors. We learn that Mr. X is a noble gentleman and that Mr. Y is a scoundrel. A moment of reflection should convince anyone that these relationships may have much to do with evolutionary success. Primitive man lived in a world in which stable interactions of personalities were very much a part of his ecological environment. He had to adjust to this set of ecological factors as well as to any other. If he was socially acceptable, some of his neighbors might bring food to himself and his family when he was temporarily incapacitated by disease or injury. In time of dearth, a stronger neighbor might rob our primitive man of food, but the neighbor would be more likely to rob a detestable primitive Mr. Y and his troublesome family. Conversely, when a poor Mr. X is sick our primitive man will, if he can, provide for him. Mr. X’s warm heart will know the emotion of gratitude and, since he recognizes his benefactor and remembers the help provided, will probably reciprocate some day. A number of people, including Darwin (1896, Chap. 5), have recognized the importance of this factor in human evolution. Darwin speaks of it as the “lowly motive” of helping others in the hope of future repayment. I see no reason why a conscious motive need be involved. It is necessary that help provided to others be occasionally reciprocated if it is to be favored by natural selection. It is not necessary that either the giver or the receiver be aware of this.

Simply stated, an individual who maximizes his friendships and minimizes his antagonisms will have an evolutionary advantage, and selection should favor those characters that promote the optimization of personal relationships. I imagine that this evolutionary factor has increased man’s capacity for altruism and compassion and has tempered his ethically less acceptable heritage of sexual and predatory aggressiveness. There is theoretically no limit to the extent and complexity of group-related behavior that this factor could produce, and the immediate goal of such behavior would always be the well-being of some other individual, often genetically unrelated. Ultimately, however, this would not be an adaptation for group benefit. It would be developed by the differential survival of individuals and would be designed for the perpetuation of the genes of the individual providing the benefit to another. It would involve only such immediate self-sacrifice for which the probability of later repayment would be sufficient justification. The natural selection of alternative alleles can foster the production of individuals willing to sacrifice their lives for their offspring, but never for mere friends.

The prerequisites for the operation of this evolutionary factor are such as to confine it to a minor fraction of the Earth’s biota. Many animals form dominance hierarchies, but these are not sufficient to produce an evolutionary advantage in mutual aid. A consistent interaction pattern between hens in a barnyard is adequately explained without postulating emotional bonds between individuals. One hen reacts to another on the basis of the social releasers that are displayed, and if individual recognition is operative, it merely adjusts the behavior towards another individual according to the immediate results of past interactions. There is no reason to believe that a hen can harbor grudges against or feel friendship toward another hen. Certainly the repayment of favors would be out of the question.

A competition for social goodwill cannot fail to have been a factor in human evolution, and I would expect that it would operate in many of the other primates. Altman (1962) described the formation of semipermanent coalitions between individuals within bands of wild rhesus monkeys and cited similar examples from other primates. Members of such coalitions helped each other in conflicts and indulged in other kinds of mutual aid. Surely an individual that had a better than average ability to form such coalitions would have an evolutionary advantage over its competitors. Perhaps this evolutionary factor might operate in the evolution of porpoises. This seems to be the most likely explanation for the very solicitous behavior that they sometimes show toward each other (Slijper, 1962, pp. 193-197). I would be reluctant, however, to recognize this factor in any group but the mammalia, and I would imagine it to be confined to a minority of this group. For the overwhelming mass of the Earth’s biota, friendship and hate are not parts of the ecological environment, and the only way for socially beneficial self-sacrifice to evolve is through the biased survival and extinction of populations, not by selective gene substitution within populations.


The observation that great new ideas often have precedents can also be made about Hamilton’s inclusive fitness theory, the best contender for most important and influential theory in social evolution. This idea, which Maynard Smith later renamed “kin selection”, was supposedly discussed informally by JBS Haldane in the 1950s.

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Maynard Smith’s apology letter in the magazine New Scientist for taking credit away from WD Hamilton and assigning it to JBS Haldane

Most people agree that the credit for the idea of kin selection must go to Hamilton. But some people attribute it to Haldane or Maynard-Smith, and much worse, I have seen many lay authors and social scientists credit the famous author Richard Dawkins with these ideas, because he popularized it in his classic 1976 book “The Selfish Gene”. For better or worse, the evolutionary success of a new idea will depend not only on its accuracy, but its ability to be understood and to thereby influence others. This is why Dawkins did more for spreading Hamilton’s ideas than Hamilton did. Credit typically goes to those who do the best job of developing and explaining the ideas’ importance to others and making it available for them to use. And sometimes the jobs of innovation, development, and popularization are best done by different people.

Scientists are motivated by getting recognition for their work, but perhaps we scientists should be explicit that we should (and do) give less credit to whoever had the idea first. If you have a good idea, there’s a good chance someone else had it first. What matters more is what you do with your ideas. The most important reason to know everything relevant that came before is to advance knowledge or develop it further without wasting time reinventing the wheel.

About Gerry Carter

I study the behavioral, sensory, and social ecology of vampire bats. http://socialbat.org.
This entry was posted in About cooperation, About science as an activity. Bookmark the permalink.

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