The problem with the studies he mentioned is the interpretation. The article he linked (note: not a study) is an interpretation of a series of studies that actually ignores the conclusion of most of them. It has a massive anti-capitalist ideological bent. Science has no political bias. It is fact, it is not, or we don't know. The article he linked is attempting to explain the results according to how it's seen through a particular 'lens'.
Philosophers have been arguing about whether people are
inherently selfish since there has been such a thing as philosophers. In Plato's "Republic," Socrates has a discussion with his older brother Glaucon in which Glaucon insists that people's good behavior actually only exists for self-interest: People only do the right thing because they fear being punished if they get caught. If human actions were invisible to others,
Glaucon says, even the most "just" man would act purely for himself and not care if he harmed anyone in the process.
It's the sort of argument that might have appealed to Thomas Hobbes, the 17th-century English philosopher famous for saying that the natural state of man's life would be "nasty, brutish and short." According to Hobbes, humans must form social contracts and governments to prevent their selfish, violent tendencies from taking over.
Not all philosophers have agreed with this dour point of view, however. Philosopher John Locke, for example, thought that humans were inherently
tolerant and reasonable, though he acknowledged humanity's
capacity for selfishness.
But philosophers are great at asking questions, not getting answers. So what does the science say? In fact, you're right in that people are quite willing to act for the good of the group, even if it's against their own interests, studies do show this. But paradoxically, social structures that attempt to give people incentives for good behavior can actually make
people more selfish.
Take a classic example: In 2000,
a study in the Journal of Legal Studies found that trying to punish bad behavior with a fine backfired spectacularly. The study took place at 10 day care centers in Haifa, Israel. First, researchers observed the centers for four weeks, tracking how many parents arrived late to pick up their children, inconveniencing the day care staff. Next, six of the centers introduced a fine for parents who arrived more than 10 minutes late. The four other centers served as a control, for comparison. (The fine was small but not insignificant, similar to what a parent might have to pay a babysitter for an hour.)
After the introduction of the fine, the rate of late pickups didn't drop. Instead, it nearly doubled. By introducing an incentive structure, the day cares apparently turned the after-school hours into a commodity, the researchers wrote. Parents who might have felt
vaguely guilty for imposing on teachers' patience before the fine now felt that a late pickup was just something they could buy.
The Haifa day care study isn't the only one to find that trying to induce 'moral' behavior with material incentives can make people less considerate of others. In a
2008 review in the journal Science, Bowles examined 41 studies of incentives and
moral behavior. He found that, in most cases,
incentives and punishments undermined moral behavior.
For example, in one study, published in 2000 in the journal World Development, researchers asked people in rural Colombia to play a game in which they had to decide how much firewood to take from a forest, with the consideration that deforestation would result in poor water quality. This game was analogous to real life for the people of the village. In some cases, people played the games in small groups but couldn't communicate about their decisions with players outside their group. In other cases, they could communicate. In a third condition, the players couldn't communicate but were given rules specifying how much firewood they could gather.
When allowed to communicate, the people in the small groups set aside self-interest and gathered less firewood for themselves, preserving water quality in the forest for the larger group as a whole. Regulations, on the other hand, had a perverse result over time: People gradually began to gather more and more firewood for themselves, risking a fine but ultimately
putting their self-interest first.
"People look for situational cues of 'acceptable behavior,'" Bowles said. "Literally dozens of experiments show that if you offer someone a money
incentive to perform a task (even one that she would have happily done without pay), this will 'turn on' the 'What's in it for me?' way of thinking, often to such an extent that the person will perform less with the incentive than without."
All of this, as well as studies that show similar behaviour in other animal species, is indicative of selfishness being a perfectly natural survival mechanism. Let's face it, one good CME hits us and goodbye all the luxuries and conveniences of modern society. What allows us to be more 'altruistic' is just that, the convenience to do so. When Mazlow's heirarchy of needs is fulfilled, we have time and energy to spare to help others achieve their's, which is in and of itself as much an element of self-interest as it is caring for others, because the survival of the species is within our self-interest. But when the survival of the species is under threat, people will become more interested in survival of the self over others. Those who remain interested in the survival of others over themselves will be taken advantage of. When civilisation, and the conveniences that make rule by law possible, are out the window, then all that is left is 'might makes right'.
The thing most people keep doing here is conflating 'selfishness' with its negative connotations, as if selfishness is antithetical to virtue. But I guarantee you, something you are doing in your life is the product of that very selfishness inherent to all of us. I would bet every cent I earn for the rest of my life that this is the case in 100% of all living things.