Evolution, spite, and ideological suicide bombs

11 October 2009

Recently we’ve seen allegations by a politician and a pundit that conservative leaders are being “spiteful” by taking positions that undermine their political foes (especially President Obama), even though these positions would seem to make them look bad. For example conservatives celebrated Obama’s failure to land the Olympics for Chicago even though this made them seem somewhat unpatriotic. Rush Limbaugh’s expression of hope that Obama fails to deliver his domestic political agenda–whether or not things get better–is another example.

This behavior has been compared to that of “bratty teenagers.” Of course, teenagers have no monopoly on juvenile spitefulness. My favorite example is from a child of a much younger age. When my son was 3 or 4, his bedtime ritual included having one of his parents gently scratch his back. On those exceedingly rare occasions when he was mad at his parents, one way he retaliated was to yell, “I’m not going to let you scratch my back tonight!”

Spite in any form raises the profound scientific question: “what’s up with that?”

Actually, the question that is raised is a deep one about the evolution of behavioral decisions that mediate selfishness and cooperation.

People interested in social evolution recognizes four kinds of patterns depending upon the benefits and costs that accrue to the parties involved. (“Parties” being an especially relevant term in this case.)

  • Selfishness: one party acts to benefit himself at the expense of another
  • Mutualism: both parties experience a net benefit (i.e., outweighing any costs of the action)
  • Altruism: one party acts in a way that benefits someone else, but at some net cost to himself
  • Spite: one party acts in a way that harms another, but he harms himself in the process

We can see all of these on display in human societies, and it is certainly anthropomorphism that motivated the naming of these categories. The scientific value of this classification is to focus attention on the pressures that may favor the evolution of different kinds of behavioral interaction in social groups.

Some of these behavioral categories are easier to account for than others. Selfishness, for example, is often assumed to be the default condition of a Darwinian world “red in tooth and claw.” Mutualism too is easy to understand, and nature–red or not in tooth and claw–abounds with examples of animals (and plants) helping each other to the mutual benefit of all. Think of bees and the flowers they pollinate: bees get food and flowers get their gametes dispersed accurately to other flowers.

Altruism has been a more of knotty problem. It has invited extensive study because there are numerous examples of apparent altruism in the animal (and human world), and because acts of self-sacrifice for others would fly in the face of a Darwinian account of evolution. This paradox has largely been resolved by recognizing that most apparently selfless acts actually result in some selfish benefit to the actor either through kinship (nepotism), reciprocity (you-scratch-my-back-and-I’ll-pay-good-money-for-it), or hidden mutualistic benefits.

This brings us to spite, which is an even harder problem than altruism because it is harder to find clear-cut cases in nature and because it is an even more challenging Darwinian paradox. How would any tendency to harm others evolve–or be allowed to persist in the face of natural selection–if it also entailed disadvantages to the harm-doer?

As mentioned, there are very few candidate examples of spite in nature, but there are some. One way to explain these is to identify hidden advantages to kin who might benefit as a consequence of a spiteful act that harms the actor. Another is to uncover “indirect reciprocity“–a spiteful act might hurt both the actor and the party that he harms (spiter and spitee?), but someone else who observes this act may benefit. If that individual (the enemy of my enemy) later turns around and helps the original actor, then the spiteful act may have been worth it. Thus, again, apparent self-sacrifice would have a self-serving consequence.

Do these explanations capture what does on in human societies, where spite is so remarkably common? Take an extreme instance of spite–suicide bombings. Here, the mildness of the term “spite” seems incommensurate to the horror of the act, but it raises the same evolutionary paradox in a particularly clear way. In the case of religiously inspired suicide bombers, the commonly understood motivation has to do with a delayed selfish benefit–eternal bliss. Science doesn’t allow recourse to supernatural payoffs, and in any case our stated motives may have nothing to do with Darwinian payoffs–the ways in which our actions affect the probability of our genes, or copies residing in kin, making it to the next generation. A Darwinian account of suicide bombings would predict that there is some selfish benefit, for example an enhancement of the well-being of the family of the bombers.

Let’s return to the somewhat milder spitefulness those who wade into political debates wearing ideological bomb vests–celebrating any failure of a political opponent even at the risk of blowing themselves up. It is not hard to imagine the selfish calculations (whether conscious or unconscious) that may underlie this stance. The key is that the failure of one’s enemy may pave the way for the future success of oneself or one’s own friends and family.

The troubling question is how the incentives wound up being set this way. It is not hard to imagine a different kind of society–because they do in fact exist–in which people can be guided by selfish motives but act in a way that benefits themselves as well as others. A society that embraces mutualism instead of spite. How have the payoffs been rigged so that spite is the attitude that prevails?


About ethologist

Professor in the Zoology Department at Michigan State University
This entry was posted in Ethology, Evolution, Religion, Science and public discourse. Bookmark the permalink.

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