[SkyBelow]

Psychology studies in the past showed people were altruistic. Then psychologist accounted for social capital/good will and worked to remove it from their altruism tests. People stopped being overly altruistic when it stopped benefitting them, likely meaning that what we see as altruism is really a failure to account for all the benefits a person expects to gain and all the negatives they expect to avoid when choosing to perform a certain action.

As for shareholders, I think that comes down to the incentive to avoid the negative outcome of being replaced. Those at the top optimize their actions to avoid being replaced which filters down through each level until it effects every level of a company. There is some variety that results from how a company chooses who to promote, but that is still an outcome of not wanting to be replaced. Promote people who you think will strengthen your own position and not those who will weaken it. This ends up being the primordial pool that spawns corporate culture.

[heterodoxxed]

The concept of altruism does not require it to be "pure" or entirely selfless. Altruism can have benefits but those benefits can exist outside of economy and into the realm of the personal, spiritual, social, etc.

In other words, that doesn't disprove altruism so much as it proves that economic self-interest is not our only motivator.