It Takes a Thief: The Evolution of Selfishness

The kindness of mankind most likely developed from our more sinister and self-serving tendencies, according to University of Arizona and Princeton University research that suggests society’s rules against selfishness are rooted in the very exploitation they condemn.

Evolutionary biologists have long struggled to explain how altruistic behavior – the seemingly selfless act of helping other members of a group at one’s own expense – can arise and remain stable in a world where individuals struggle to survive and try to outcompete each other, encouraging selfish behavior of free-loaders that leech their altruistic peers until the community collapses.

Enter “selfish punishment,” a concept developed by evolutionary biologist Omar Tonsi Eldakar, who recently completed his postdoctoral fellowship in the UA’s department of ecology and evolutionary biology.

A healthy dose of a few selfish individuals in a community of altruistic individuals can benefit the whole group – that is the main conclusion of a paper, which Eldakar published together with Andrew Gallup, a former Princeton postdoctoral researcher in ecology and evolutionary biology who now is a visiting assistant professor of psychology at Bard College, and William Driscoll, who obtained his doctorate in the UA’s department of ecology and evolutionary biology and recently published a paper on cheating in algae.

In theory, a community of altruistic individuals who all work toward a common good should invite cheating, along the lines of, “Why not cut a corner here or there as long as I still get to reap the benefits provided by all?” Over time, as more and more turn to cheating behavior, it is easy to see how the community is doomed.

Traditionally, evolutionary scientists focused on strategies used by the altruists to keep the selfish cheaters out. The report in the journal Evolution proposes that altruism did not develop as a way of the altruists to protect themselves from the avarice of the selfish. Instead, communal disavowal of greed originated when competing selfish individuals sought to control and cancel out one another.

A viable scenario of co-existence and mutual benefit arises, so the authors found, when the selfish cheaters police the community and punish those who try to do the same. Over time, the direct efforts of the dominant fat cats to contain a few competitors evolved into a community-wide desire to guard its own well-being.

“The gist of the paper is that not only altruists, but selfish individuals also do better when surrounded by altruists,” said Eldakar, now a visiting assistant professor of biology at Oberlin College. “Therefore it should not be surprising that selfish individuals would police others’ selfishness.”

“Think of the Mafia: They are criminals but actually reduce criminal activity in their communities. When we model all this out using game theory, we actually find that the notion ‘it takes a thief to catch a thief’ is actually true.”

Eldakar went on to explain that cheaters by default have more resources and a greater ability to catch other cheaters than some concerned altruists.

“The cheaters are better at policing other cheaters because they reinvest the resources from exploitation to keep other exploiters out. Over time, this initially exploitative relationship actually creates a division of labor whereby cheaters protect flocks of altruists by taking the burden of protection off their backs.”

Eldakar and his co-authors suggest that a system of greed dominating greed is simply more effective at purging out cheaters and possibly easier for our human ancestors to manage.

To test their hypothesis, the researchers constructed a simulation model that gauged how a community withstands a system built on altruistic punishment, or selfish-on-selfish punishment. They found that altruism demands a lot of initial expenditure for the group – in terms of communal time, resources and risk of reprisal from the punished – as well as advanced levels of cognition and cooperation.

On the other hand, a construct in which a few profligate players keep like-minded individuals in check involves only those members of the community – everyone else can passively enjoy the benefits of fewer people taking more than their share. At the same time, the reigning individuals enjoy uncontested spoils and, in some cases, reverence.

“Mathematically speaking, funds collected from exploitation and using them for protection of the group isn’t that much different from paying taxes,” Eldakar said. “The only difference is in how we see that relationship: There was a time when the knights of the Middle Ages were looked at as bullies and thugs that exploited the peasants, but later were revered as great protectors of the people.” Social orders maintained by those who bend the rules play out in nature and human history, the authors note: Tree wasps that police hives to make sure that no member other than the queen lays eggs often will lay illicit eggs themselves. Cancer cells will prevent other tumors from forming.

“Is this corrupt policing or simply their payment for maintaining the social order of the colony?” Eldakar said.

What comes from these arrangements, the researchers conclude, is a sense of order and equality that the group eventually takes upon itself to enforce, thus giving rise to widespread altruism.

This work was supported by the National Institutes of Health.