PLoS ONE 6(7): e21437. doi:10.1371/journal.pone.0021437
The Demographic Benefits of Belligerence and Bravery: Defeated Group Repopulation or Victorious Group Size Expansion?
Laurent Lehmann
Intraspecific coalitional aggression between groups of individuals is a widespread trait in the animal world. It occurs in invertebrates and vertebrates, and is prevalent in humans. What are the conditions under which coalitional aggression evolves in natural populations? In this article, I develop a mathematical model delineating conditions where natural selection can favor the coevolution of belligerence and bravery between small-scale societies. Belligerence increases an actor's group probability of trying to conquer another group and bravery increase the actors's group probability of defeating an attacked group. The model takes into account two different types of demographic scenarios that may lead to the coevolution of belligerence and bravery. Under the first, the fitness benefits driving the coevolution of belligerence and bravery come through the repopulation of defeated groups by fission of victorious ones. Under the second demographic scenario, the fitness benefits come through a temporary increase in the local carrying capacity of victorious groups, after transfer of resources from defeated groups to victorious ones. The analysis of the model suggests that the selective pressures on belligerence and bravery are stronger when defeated groups can be repopulated by victorious ones. The analysis also suggests that, depending on the shape of the contest success function, costly bravery can evolve in groups of any size.
Link
"bravery increase[s] the actors's group probability of defeating an attacked group."
ReplyDeleteWhen does bravery become foolhardy?
I have doubts that there is a general increase of probability of success in conflicts with other groups that results from bravery.
Likewise, belligerence has costs as well as benefits that have to be accounted for, and it isn't clear that this model does.
It may be the case, however, the either a "peaceful and cautious" or a "belligerent and brave" strategy are better than middle ground.
In other words, War is a positive factor in the evolution of the species, which works through the survival of the fittest.
ReplyDeleteWar selects those tribes who are best fitted to combat. It encourages all sorts of qualities - strength, discipline, perseverance, hardiness, group co-operation, ruthlessness etc.
This raises the ethical issue that perhaps our modern "morality", which condemns war and aggression, is actually a hindrance to the evolution of the human species.
Perhaps pacifism, charity, foreign aid and global co-operation is actually retarding the human species and leading to a genetic regression that will weaken the species for thousands of years to come.
"All beings hitherto have created something beyond themselves: and ye want to be the ebb of that great tide, and would rather go back to the beast than surpass man?" (Nietzsche)
"Perhaps pacifism, charity, foreign aid and global co-operation is actually retarding the human species and leading to a genetic regression that will weaken the species for thousands of years to come."
ReplyDeleteWe are at the brink of "Post-Evolution Age".
Man will alter his own DNA to what he wants it to be.
Also, mashines will surpass man in this century. And man will become a pampered baby, a pet at the feet of the mashines. Maybe he will become a borg (Biology-mashine hybrid) to be not THAT much inferior to the mashines.
So I really dont care, where evolution would lead us. We kill evolution. We decide what will happen.