On Andrew Gelman’s blog he often reprints emails he receives and his responses when he thinks they may be interesting to his readers. This post will be my first attempt at that.  However, I once surprised a friend when congratulating him on his email being answered on Gelman’s blog. So, unlike Gelman, I plan to always ask permission first.

Ed LeGrand writes:

At the 2010 Human Evolution & Behavior Society meeting I met Paul Bingham, who discussed his ideas in his book, Death from a Distance. Intrigued, I bought and read it and have since wondered why I'm not hearing discussion of it in, since it sounds so reasonable.

Bingham's premise is that the evolution of weaponry goes hand-in-hand with the evolution of social size and the size of political systems (of course, there are hundreds of correlates!). As you mentioned, chimps need about a 4:1 advantage before attacking with a reasonable degree of safety. Bingham would point out that because of spatial limitations, not many more than 3-4 individuals can be involved in hand-to-hand combat against an opponent at a time. Because the victim may be large or skilled, there's a rather high risk that one of the attackers will get injured. Bingham views this attack from the standpoint of group members disciplining/punishing a transgressor. Once a method of killing from a distance (throwing rocks) developed, the odds changed dramatically. It now becomes much safer to punish transgressors. Rather than 3-5 group members trying to punish one person and suffering the real risk of physical injury (a 4:1 advantage for the attackers), they can administer punishment at a distance. Not only is it physical safer, but now there are 4 people throwing rocks at one person, who can throw one rock at 4 people (a 4^2:1 advantage). The farther away one can be from the transgressor, the more physical space there can be for discipliners. With the development of new weaponry, a group of 100 people can easily simultaneously send 100 arrows at a transgressor (or victim) while only 1 arrow gets sent back at the 100 people (a 100^2:1 safety factor for the attackers).  Bingham's book follows the development of weapons (spears, arrows, firearms, etc.) and notes that the advantage is greatly magnified. Bingham suggests that the size of the group/hierarchy is causally associated with the ability to control transgressors (or the ability of a dictator to control his subjects). In warfare, this ability to deliver death from a distance greatly increases the advantage of having the new technology. As a defense, the opponents without the most advanced weaponry have no choice but to join a larger group, and so on (I'm condensing a couple of hundred pages of argument and examples). The epitome of this is the advent of nuclear weapons where punishment of a whole country can be administered by the push of a button at great distance. Bingham pointed out that this has pushed the world into a huge single society. Drones aren't mentioned, but that's like the technology of a whole society being directed at specific transgressors from the safety of being on the other side of the globe.

Anyway, you may have heard of the conceptual model. If not, it's one to at least be aware of. I'd think the advantage of weaponry for easier and safer ability to effect punishment or to extend one's will would lend itself to interesting mathematical modeling.

My reply:

I had not heard of this specific thesis, but it reminds me of some of the ideas in Boehm’s Hierarchy in the Forest. Boehm’s story is actually somewhat opposite. He posits that human groups was once fairly similar to chimpanzee groups – physically dominant males were at the top of a social hierarchy and maintained their social status by, basically, brute strength against all challengers. Weaponry allowed less dominant individuals to effectively gang up on any would-be dominant male and invert the hierarchy – creating fairly egalitarian groups. In his story, death from a distance creates the conditions for less social control.

It seems like what should be important, in addition to total killing power, is how killing power is distributed. With Boehm’s chimpanzees and with the nuclear weapons in your example, power is concentrated in the elites (or there are elites because power is concentrated).  In Boehm’s egalitarian groups and in the bow-and-arrow example from your email, power is fairly widely distributed. I hadn’t really thought about it in terms of weaponry, but I think this is probably important for understanding the size of hierarchies.  I’ll check out Bingham’s book.