I would question your conflation of agreeableness with altruism. Tests of agreeableness conflate different traits, I always thought Europeans were just as high in altruism as East asians but just less conformist giving us lower agreeableness scores. But I've never seen comparisons of them doing the dictator game so I could be wrong I guess. I wouldn't say that Europeans dominating the world over Asians is strong evidence against group selection for altruism, it's probably just other traits that Asians have that stopped them from starting an industrial revolution like low Openness. Both seem high in altruism compared to the primitive low trust societies that failed to develop.
With regard to group selection, I think it needs to be disambiguated, so that we know which form you're referring to - because there's more than one sense of the term "group selection". A plausible form of group selection is "cultural group-selection": that refers to culture evolving in response to some form of competition between groups. In which case - and here I'm being speculative - it may be that moderate agreeableness is optimal. Perhaps because it simultaneously allows people to cooperate sufficiently with group members but to discount the interests of members from outside groups. In any case, an explanation in terms of cultural group-selection doesn't necessarily need to invoke selection pressures on alleles for agreeableness per se, via the feedback process that culture can have on the gene pool. Rather, the average or modal level of agreeableness seen in a society could be to a large extent moderated simply by that society's cultural norms and practices. And perhaps societies in Europe evolved to be closer to that cultural optimum, for various historical reasons. Furthermore, this kind of cultural group-selection-fuelled optimization could have regulated the evolved tribal psychology of humans: it could help regulate just how cooperative the average person is with an in-group member, and how hostile or ambivalent they are with respect to out-groups.
Narcissism is an interesting word and I note the mythical origin in Narcissus who admired his own reflection. There is this meaning which basically denotes admiring oneself excessively or having an inflated view of one's own virtues, and there is interesting exploration of that side here which seems sound.
However, I think the definitions emphasise 'excessive' preference for oneself and disregard for others, which is similar to the Britannica definition which seems to lean towards the psychiatric idea of the condition, narcissistic personality disorder. There are other nuances to the disorder like the need for admiration mentioned in the DSM. Thinking of the psychiatric concept, it doesn't seem right to say that a disorder is the default, which would belie its nature as a 'dis' -order.
I think the dictator games data does show selfishness but I wouldn't say it is 'excessive' and it seems a slightly contrived scenario which doesn't reflect that humans are more likely to be selfless or pro-social in other more natural and common situations. I would expect the average person to take all or most of a pot of money given to them out of the blue rather than give it to a stranger, and they'd consider that justified, but I would expect more pro-social or generous behaviour towards someone from an in group, friends or family, and also to a stranger in a co-operative project that yields a reward.
For example if a person worked on a project with a relative stranger that resulted in money or another reward, I guess they would be unlikely to try to take all of the reward for themselves, even if they could get away with it, again especially if it was a friend or family. The point is that it is normal to look after oneself in the first instance, but also normal to help others a lot of the time. Infants, which have undergone the least socialisation, display pro-social helping behaviours at very early ages.
There's also perhaps an imbalance in arguing that selfless actions may be implicitly selfish but not that selfish actions can't be implicitly selfless. Many people would and do argue that each person looking out for themselves foremost is the optimal basis for society at large.
There may be selfish rationale behind seemingly generous actions - but I don't buy the idea that if generosity makes someone feel good then it's actually selfish. I think the cause and effect is swapped here to what is supposed; giving to another person would only have positive emotional feedback for someone if they internally valued the action. If someone truly believed it was not valuable to give to another person, then I don't think they would get the 'selfish' emotional reward.
Also, possibly more than particularly valuing others or oneself, I suspect humans instinctively adhere to a principle of fairness in interactions with others, where they tend to avoid taking or giving excessively (this is reduced or absent in psychopaths or narcissists). This is to say that people balance the needs of self and other, but I wouldn't characterise them as naturally overall selfish.
I would question your conflation of agreeableness with altruism. Tests of agreeableness conflate different traits, I always thought Europeans were just as high in altruism as East asians but just less conformist giving us lower agreeableness scores. But I've never seen comparisons of them doing the dictator game so I could be wrong I guess. I wouldn't say that Europeans dominating the world over Asians is strong evidence against group selection for altruism, it's probably just other traits that Asians have that stopped them from starting an industrial revolution like low Openness. Both seem high in altruism compared to the primitive low trust societies that failed to develop.
So real
With regard to group selection, I think it needs to be disambiguated, so that we know which form you're referring to - because there's more than one sense of the term "group selection". A plausible form of group selection is "cultural group-selection": that refers to culture evolving in response to some form of competition between groups. In which case - and here I'm being speculative - it may be that moderate agreeableness is optimal. Perhaps because it simultaneously allows people to cooperate sufficiently with group members but to discount the interests of members from outside groups. In any case, an explanation in terms of cultural group-selection doesn't necessarily need to invoke selection pressures on alleles for agreeableness per se, via the feedback process that culture can have on the gene pool. Rather, the average or modal level of agreeableness seen in a society could be to a large extent moderated simply by that society's cultural norms and practices. And perhaps societies in Europe evolved to be closer to that cultural optimum, for various historical reasons. Furthermore, this kind of cultural group-selection-fuelled optimization could have regulated the evolved tribal psychology of humans: it could help regulate just how cooperative the average person is with an in-group member, and how hostile or ambivalent they are with respect to out-groups.
Narcissism is an interesting word and I note the mythical origin in Narcissus who admired his own reflection. There is this meaning which basically denotes admiring oneself excessively or having an inflated view of one's own virtues, and there is interesting exploration of that side here which seems sound.
However, I think the definitions emphasise 'excessive' preference for oneself and disregard for others, which is similar to the Britannica definition which seems to lean towards the psychiatric idea of the condition, narcissistic personality disorder. There are other nuances to the disorder like the need for admiration mentioned in the DSM. Thinking of the psychiatric concept, it doesn't seem right to say that a disorder is the default, which would belie its nature as a 'dis' -order.
I think the dictator games data does show selfishness but I wouldn't say it is 'excessive' and it seems a slightly contrived scenario which doesn't reflect that humans are more likely to be selfless or pro-social in other more natural and common situations. I would expect the average person to take all or most of a pot of money given to them out of the blue rather than give it to a stranger, and they'd consider that justified, but I would expect more pro-social or generous behaviour towards someone from an in group, friends or family, and also to a stranger in a co-operative project that yields a reward.
For example if a person worked on a project with a relative stranger that resulted in money or another reward, I guess they would be unlikely to try to take all of the reward for themselves, even if they could get away with it, again especially if it was a friend or family. The point is that it is normal to look after oneself in the first instance, but also normal to help others a lot of the time. Infants, which have undergone the least socialisation, display pro-social helping behaviours at very early ages.
There's also perhaps an imbalance in arguing that selfless actions may be implicitly selfish but not that selfish actions can't be implicitly selfless. Many people would and do argue that each person looking out for themselves foremost is the optimal basis for society at large.
There may be selfish rationale behind seemingly generous actions - but I don't buy the idea that if generosity makes someone feel good then it's actually selfish. I think the cause and effect is swapped here to what is supposed; giving to another person would only have positive emotional feedback for someone if they internally valued the action. If someone truly believed it was not valuable to give to another person, then I don't think they would get the 'selfish' emotional reward.
Also, possibly more than particularly valuing others or oneself, I suspect humans instinctively adhere to a principle of fairness in interactions with others, where they tend to avoid taking or giving excessively (this is reduced or absent in psychopaths or narcissists). This is to say that people balance the needs of self and other, but I wouldn't characterise them as naturally overall selfish.