>>515033553

Ayup. In fact it's so intuitive and obvious you literally have to be brainwashed out of it.

The Evolutionary Dominance of Ethnocentric Cooperation, Hartshorn et. al.
https://jasss.soc.surrey.ac.uk/16/3/7.html
>Here we show that ethnocentrism eventually overcomes its closest competitor, humanitarianism, by exploiting humanitarian cooperation across group boundaries as world population saturates.
>Selfish and traitorous strategies are self-limiting because such agents do not cooperate with agents sharing the same genes.


https://pubmed.ncbi.nlm.nih.gov/25576843/

The Emergence of Relationship-based Cooperation
Bo Xu et al.
https://pubmed.ncbi.nlm.nih.gov/26567904/
>We construct the model by categorizing game participants into four types: prosocialists (players who prefers to invest in their intimate friends), antisocialists (players who prefer to invest in strangers), egoists (players who never cooperate) and altruists (players who cooperate indifferently with anyone). We show that the relationship-based cooperation (prosocialists) is favored throughout the evolution if we assume players of the same type have stronger ties than different ones. Moreover, we discover that strengthening the internal bonds within the strategic clusters further promotes the competitiveness of prosocialists and therefore facilitates the emergence of relationship-based cooperation in our proposed scenarios.