(cross-posted from my blog)
I think that tribalism is one of the biggest problems with humanity today, and that even small reductions of it could cause a massive boost to well-being.
By tribalism, I basically mean the phenomenon where arguments and actions are primarily evaluated based on who makes them and which group they seem to support, not anything else. E.g. if a group thinks that X is bad, then it's often seen as outright immoral to make an argument which would imply that X isn't quite as bad, or that some things which are classified as X would be more correctly classified as non-X instead. I don't want to give any specific examples so as to not derail the discussion, but hopefully everyone can think of some; the article "Can Democracy Survive Tribalism" lists lot of them, picked from various sides of the political spectrum.
Joshua Greene (among others) makes the argument, in his book Moral Tribes, that tribalism exists for the purpose of coordinating aggression and alliances against other groups (so that you can kill them and take their stuff, basically). It specifically exists for the purpose of making you hurt others, as well as defend yourself against people who would hurt you. And while defending yourself against people who would hurt you is clearly good, attacking others is clearly not. And everything being viewed in tribal terms means that we can't make much progress on things that actually matter: as someone commented, "people are fine with randomized controlled trials in policy, as long as the trials are on things that nobody cares about".
Given how deep tribalism sits in the human psyche, it seems unlikely that we'll be getting rid of it anytime soon. That said, there do seem to be a number of things that affect the amount of tribalism we have:
* As Steven Pinker argues in The Better Angels of Our Nature, violence in general has declined over historical time, replaced by more cooperation and an assumption of human rights; Democrats and Republicans may still hate each other, but they generally agree that they still shouldn't be killing each other.
* As a purely anecdotal observation, I seem to get the feeling that people on the autism spectrum tend to be less tribal, up to the point of not being able to perceive tribes at all. (this suggests, somewhat oddly, that the world would actually be a better place if everyone was slightly autistic)
* Feelings of safety or threat seem to play a lot into feelings of tribalism: if you perceive (correctly or incorrectly) that a group Y is out to get you and that they are a real threat to you, then you will react much more aggressively to any claims that might be read as supporting Y. Conversely, if you feel safe and secure, then you are much less likely to feel the need to attack others.
The last point is especially troublesome, since it can give rise to self-fulfilling predictions. Say that Alice says something to Bob, and Bob misperceives this as an insult; Bob feels threatened so snaps at Alice, and now Alice feels threatened as well, so shouts back. The same kind of phenomenon seems to be going on a much larger scale: whenever someone perceives a threat, they are no longer willing to give someone the benefit of doubt, and would rather treat the other person as an enemy. (which isn't too surprising, since it makes evolutionary sense: if someone is out to get you, then the cost of misclassifying them as a friend is much bigger than the cost of misclassifying a would-be friend as an enemy. you can always find new friends, but it only takes one person to get near you and hurt you really bad)
One implication might be that general mental health work, not only in the conventional sense of "healing disorders", but also the positive psychology-style mental health work that actively seeks to make people happy rather than just fine, could be even more valuable for society than we've previously thought. Curing depression etc. would be enormously valuable even by itself, but if we could figure out how to make people generally happier and resilient to negative events, then fewer things would threaten their well-being and they would perceive fewer things as being threats, reducing tribalism.
Can you say what you think is more valuable? If i'm looking at GW's top charities, the options are AMF or SCI. AMF is about saving lives, rather than improving lives, so that's a moral question as to how you trade those off. I'm not really sure how to think of the happiness impact of SCI. GW seem to argue it's worthwhile because it increases income for the recipient, but I'm pretty sceptical increases in income, even at low levels, improve aggergrate happiness (see this paper on Give Directly that found it didn't increase overall happiness)
I don't think mental health has comparably good interventions to either of these, even given the caveats you note. Cost per QALY or similar for treatment looks to have central estimates much higher than these, and we should probably guess mental health interventions in poor countries have more regression to the mean to go.
Some hypothetical future intervention could be much better, but looking for these isn't that neglected, and such progress looks intractable given we understand the biology of a given common mental illness much more poorly than a typical NTD.