A chain of speculative scientific reasoning from our work into really big social/society questions:

1. Skill learning is a thing. If we practice something we get better at it and the learning curve goes on for a long time, 10,000 hours or more.  Because we can keep getting better for so many hours, nobody can really be a top-notch expert at everything (there isn’t time).  This is, therefore, among the many reasons why in group-level social functioning it is much better to specialize and have multi-person projects done by teams of people specializing in component steps (for tasks that are repeated regularly).  The economic benefits of specialization are massive and straightforward.
2. However, getting people to work well in teams is hard. In most areas requiring cooperation, there is the possibility of ‘defecting’ instead of cooperating on progress – to borrow terms from the Prisoner’s Dilemma formalism.  That powerful little bit of game theory points out that in almost every one-time 2-person interaction, it’s always better to ‘defect,’ that is, to act in your own self-interest and screw over the other player.
3. Yet, people don’t. In general, people are more altruistic than overly simple game-theory math would predict.  Ideas for why that model is wrong include (a) extending the model to repeated interactions where we can track our history with other players and therefore cooperation is rewarded by building a reputation; (b) that humans are genetically prewired for altruism (e.g., perhaps by getting internal extra reward from cooperating/helping); or (c) that social groups function by incorporating ‘punishers’ who provide extra negative feedback for the non-cooperators to reduce non-cooperation.
4. These three alternatives aren’t mutually exclusive, but further consideration of the (3a) theory raises some interesting questions about cognitive capacity. We interact a lot with a lot of different people in our daily lives.  Is it possible to track and remember everything about our interactions in order to make optimal cooperate/defect decisions?  Herb Simon argued (Science, 1980) that we can’t possibly do this, working along the same lines as his ‘bounded rationality’ reasoning that won him the Nobel Prize in Economics.  His conclusion was that (3b) was more likely and showed that if there was a gene for altruism (he called it ‘docility’), it would breed into the population pretty effectively.
5. No such gene has yet been identified and I have spent some time thinking about alternate approaches based on potential cognitive mechanisms for dealing with the information overload of tracking everybody’s reputation. One really interesting heuristic I ran is the Symmetry Hypothesis, which I have slightly recast for simplicity.  This idea is a hack to the PD where you can reason very simply as follows: If the person I am interacting with is just like me and reasons exactly as I do, no matter what I decide, they are going to do the same and in this case, I can safely cooperate because the other player will too.  And if I defect, they will also (potentially allowing group social gains through competition, which is a separate set of ideas).
6. Symmetry would apply in cases where the people you often interact with are cognitively homogeneous, that is, where everybody thinks ‘we all think alike.’ Here, where ‘we’ can be any social group (family, neighborhood, community, church, club, etc.).   If this is driving some decent fraction of altruistic behavior, you’d see strong tendencies for high levels of in-group trust (compared with out-group), and particularly in groups that push people towards thinking similarly.  You clearly do see those things, but their existence doesn’t actually test the hypothesis – there are many theories that predict in-group/out-group formation, that these affect trust, that people who identify in a group start to think similarly.  Of note, though, this idea is a little pessimistic because it suggests that groupthink leads to better trust and social grouping should tend to treat novel, independent thinkers poorly.
7. Testing the theory would require data examining how important ‘thinks like me’ is to altruistic behavior and/or how important cognitive homogeneity is to existing strong social groups/identity. This is a potential area of social science research a bit outside our expertise here in the lab.
8. But if true, the learning-related question (back to our work) is whether a tendency to rely on symmetry can be learned from our environment. I suspect yes, that feedback from successful social interactions would quickly reinforce and strengthen dependency on this heuristic.  I think that this could cause social groups to become more cognitively homogeneous in order to be more effectively cohesive.  Cognitively homogeneous groups would have higher trust, cooperate better and be more productive than non-homogeneous groups, out-competing them.  This could very well create a kind of cultural learning that would persist and look a lot like a genetic factor.  But if it was learned (rather than prewired), that would suggest we could increase trust and altruism beyond what we currently see in the world by learning to allow more diverse cognitive approaches and/or learning to better trust out-groups.

I was moved to re-iterate this chain of ideas because it came up yet again in conversational drive into politics among people in the lab.  Although our internal debates usually center around how different groups treat the out-groups and why.  Yesterday, the discussion started with observing that people we didn’t agree with seemed often to be driven by fear/distrust/hate of those in their out-groups.  However, it was not clear that if you didn’t feel that way, whether you had managed to see all of humanity as your in-group or instead had found/constructed an in-group that avoided negative perception of the out-groups.  We did not come to a conclusion.

FWIW, this line of thinking depends heavily on the Symmetry idea, which I discovered roughly 10 years ago via Brad DeLong’s blog (http://delong.typepad.com/sdj/2007/02/the_symmetry_ar.html).  According to the discussion there, it is also described as the Symmetry Fallacy and not positively viewed among real decision scientists.  I have recast it slightly differently here and suspect that among the annoying elements is that I’m using an underspecified model of bounded rationality.  That is, for me to trust you because you think like me, I’m assuming both of us have slightly non-rational decision processes that for unspecified reasons come to the same conclusion that we are going to trust each other.  Maybe there’s a style issue where a cognitive psychologist can accept a ‘missing step’ like this in thinking (we deal with lots of missing steps in cognitive processing) where a more logic/math approach considers that anathema.