Friday, April 24, 2015

A History of Violence

Two perennial and obviously closely related questions in the biosocial sciences are whether human beings are violent by nature and whether our close relatives among the great apes are violent by nature.  It is obvious that human beings and chimpanzees display violent behavior in fact, both within groups (politics) and between groups (war).  For those inclined to believe that such violence is not the produce of evolution but instead a result of unnatural environmental factors (which is to say, factors that did not constitute substantial selection pressures during their evolution), there are a number of available arguments. 
One is that the last twelve thousand years have seen the rise of social conditions among human beings that are very different from those in which any primate ever lived before.  Large surpluses and the social stratification that was made possible by those surpluses gave human beings something to fight about.  That is the most plausible case for the thesis that violence is accidental rather than natural to our species.  It flies in the face of evidence that human beings were more violent in hunter-gatherer societies that approximate the environment of evolutionary adaptation. 
A second argument is that human beings are largely responsible for chimpanzee violence.  Humans have put enormous stress on chimpanzees (by restricting their foraging ranges, etc.) and this, not their nature, is to blame.  For a third argument, one may look to our other cousins, the bonobos.  These animals do not fight wars, organize hunts, or display much interpersonal violence in their groups. 
To make the bonobo argument plausible, one would have to explain why the same artificial pressures that make chimpanzees violent have not had the same effect on bonobos.  If it has, I have not seen it reported.  The absence of violence among bonobos is thought to result from the power of female coalitions.  These coalitions are built upon networks of sexual partnerships among the females and function to protect the sons of the coalition partners. 
The problem with using bonobos to argue that the three species are not inherently violent is that is raises the question of what the female coalitions arose to do in the first place.  Mothers collective protect their sons, which they would not have to do if their sons did not need protection.  That this has been going on for long enough to modify the bonobo’s evolution is evident from the fact that bonobo males are considerably smaller and less robust than chimpanzee males. 
Competition for status among males is less intense and largely nonviolent but it is not absent.  Males who have living mothers are apparently advantaged in status competition over motherless males.  Motherless males are also subject to much more aggression by other males, especially when they are young.  It appears that bonobos are the exception that proves the rule.  Their tendencies to interpersonal violence are not absent, they are merely suppressed by a special feature of pan paniscus evolution. 
As for chimpanzees, a study published in Nature does short work with the excuses for violence in this species.  From a summary in The Washington Post:
The paper, which analyzed data from 426 combined years of observation and 18 separate chimp sites, argues chimps are not driven to violence by their contacts with humans, which some scientists have previously contended. Chimps, rather, are natural born killers.
“Variation in killing rates was unrelated to measures of human impacts,” said the paper, which was researched by an international team of 30 scientists. “… The adaptive strategies hypothesis views killing as an evolved tactic by which killers tend to increase their fitness through increased access to territory, food, mates and other benefits.”
The research feeds into a lengthy debate over the nature of chimp violence, and what it means for humanity’s own propensity for murder. “We’re trying to make inferences about human evolution,” lead researcher Michael L. Wilson, an anthropologist at the University of Minnesota, told the New York Times. Even in areas where humanity’s hand and habitat loss were not discernible, the chimps conveyed the same bellicosity, the research found. It signified that competition over resources— even when abundant — drove the chimp wars.
So if chimpanzees are not less violent where human influences are not felt and resources are abundant and bonobos are not more violent where human influences cause stress, then it seems clear that pan troglodyte is in fact violent by nature and bonobos not.  If bonobos are less violent not because aggressive tendencies are absent but because they have been suppressed by another evolutionary adaptation, then it seems likely that the tendencies toward violent aggression have been inherited by both species from their common pan ancestors.  Finally, if human beings were more troglodyte in behavior than paniscus in their behavior before the rise of settled agriculture, then it seems likely that the history of violence stretches back to the common ancestors of all three species. 
This has significant implications for political philosophy.  Jean Jacques Rousseau argued precisely that human beings were asocial and therefore non-aggressive by nature.  It was only a terrible accident of history that drove human beings together and created the conditions for inequality and violence.  Rousseau was wrong. 
Thomas Hobbes argued not that human beings were violent by nature but that the logic of their situation when they meet drives them in the direction of violence.  I might get what I want by killing you and you, knowing this, have an incentive to kill me first.  Hobbes was closer to the truth, but failed to consider that such logic would have to be partially built-in to be effective.  The context works by triggering instincts.  If our instincts were not Hobbesian, neither would be our behavior. 
John Locke supposed that what really made us dangerous was our inherent sense of justice.  Our tendency to invoke the executive power that belongs to everyone by nature can make really enemies out of human parties, each of which thinks it has been wronged by the other.  Locke was pretty much dead spot on.  Our moral instincts are built upon the political and territorial instincts of our ape (or proto-ape) ancestors. 
All three of these early modern philosophers were, however, proceeding on the basis of a big mistake.  They supposed that man is by nature an isolated animal.  Not only political institutions but all human societies are largely accidental.  As the nature of a wall does not change much the nature of bricks, so what is natural to us is only what we bring to any society of which be become a part. 
Aristotle did not make that mistake.  Just as a biologist cannot recognize a gene except by recognizing the function it has in the cellular machinery, so we cannot understand the nature of a single human being except by recognizing how he or she shapes and is shaped by social and indeed moral and political communities.  It remains the fact that we do carry with us a nature that contains our evolutionary history within it.  The three homo species (to use a proposed and, I think, correct specification) carry with them a history of violence. 

1 comment:

  1. This is a very nice summary of the many weaknesses of the argument that the capacity for violence in H. sapiens is not an adaptation. I've always noticed that I look a lot sharper in the mirror than I ever do in photos (reality). For some time, among a few scientists at least, the same kind of delusional thinking has pervaded thinking about H. sapiens and the capacity for violence.