Cooperation or Altruism or Prosociality is the tendency to help others, even at a cost to oneself. Naive conceptions of evolution, make us think that cooperation or altruism cannot evolve because the genes are selfish and only care about perpetuating themselves. However, the selfish gene view of evolution does not preclude organisms to become altruistic if for example they share genes ; one of the mechanisms for the same is kin selection.
Another mechanism that can give rise to cooperation is direct reciprocal altruism. In colloquial language, it is akin to you scratch my back and I’ll scratch yours. You help someone in their time of need and expect that the person will help you back in your time of need. Consider our hunter/ gatherer ancestors; if one of them made a big kill and shared with a con-specific, it becomes more likely that the peer will share with him when good fortune shines on the peer.
A necessary condition for reciprocal altruism to evolve is the ability to punish if someone doesn’t reciprocate or at least to not keep trusting that freeloader in future. Both punishment as well as not indulging with that person again or repaying a past benefactor, depends on the ability to remember the person whom who we have helped or who has helped us. This ability will typically involve remembering faces. Another ability that will come handy is the ability to gauge intentions- whether the person who helped did it on purpose or accidentally.
Yet another mechanism that gives rise to cooperation is indirect reciprocity. I help you and you help someone else. While in direct reciprocity, a pair or dyad helps each other over time or helps now with the hope/ expectation of a payoff in the future; in indirect reciprocity, one helps a stranger just because one has been helped by someone. Indirect reciprocity works by creating a culture of altruism, where helping becomes the norm and people accumulate reputations.
Now, direct reciprocity can work by encouraging feelings of gratitude in a beneficiary. These feelings of thankfulness and indebtedness towards the benefactor , act together to ensure that the person receiving favors, returns them.
Indirect reciprocity works similarly, by promoting feelings of elevation or inspiration in the general public who may be recipient or even just witnessing a virtuous act of kindness, morality etc. . Once such feelings are aroused, the person witnessing such acts become more likely to act prosocially.
The above may seem speculative, but there is solid evidence around the evolution of direct reciprocity as well as indirect reciprocity. and so too is there strong linkage between direct reciprocity and gratitude. The link between indirect reciprocity and elevation is also hinted.
For example, consider the following article by Sui et al that shows that trait gratitude and trait elevation have different neural correlates. From the abstract:
We demonstrated that trait gratitude was positively correlated with gray matter volume (GMV) in the left cerebellum extending to fusiform gyrus, and also the right middle occipital gyrus (MOG) extending to posterior superior temporal sulcus (pSTS) and temporoparietal junction (TPJ), while trait elevation was negatively correlated with GMV in the left dorsolateral prefrontal cortex. While controlling each other, all the regions still held significant, except the right MOG and pSTS/TPJ. The results indicate that there are distinct neuroanatomical correlates for proneness to gratitude and elevation, while the evidence is mixed that pSTS/TPJ may be the common correlates for them.
The authors discuss the implications of above: gratitude is associated with more GMV in fusiform gyrus, an area important for remembering faces, and is thus the emotion associated with direct reciprocity where remembering faces is important. Also, both gratitude/ elevation are associated with pSTS and TPJ, areas important for attributing and inferring intentions to others. Elevation further is negatively associated with GMV in left DLPFC, a region that involves thinking in a utilitarian manner rather than in intuitive manner about moral issues. As per dual process theories of morality one can either take a intuitive, de-ontological stand where a moral act is moral because it is the right thing to do or a duty to uphold; or the second pathway consists of more deliberate, utilitarian reasoning whereby one looks at acting such that happiness/utility is maximized for maximum number of people. Trolley problems are famous examples of such utilitarian reasoning battling with moral intuitions.
To me the differential neural correlates of gratitude and elevation, as well their different manifestations at the emotion and behavioral level, strongly suggest that they are associated with different types of altruism- direct and indirect respectively.