Here is a description (about 5000 wds, or roughly 10 pages) of
biological altruism from Stanford U., which is directly pertinent here.
Some key points:
Stanford said:
In evolutionary biology, an organism is said to behave altruistically when its behaviour benefits other organisms, at a cost to itself. The costs and benefits are measured in terms of reproductive fitness, or expected number of offspring. So by behaving altruistically, an organism reduces the number of offspring it is likely to produce itself, but boosts the number that other organisms are likely to produce. This biological notion of altruism is not identical to the everyday concept. In everyday parlance, an action would only be called ‘altruistic’ if it was done with the conscious intention of helping another. But in the biological sense there is no such requirement. Indeed, some of the most interesting examples of biological altruism are found among creatures that are (presumably) not capable of conscious thought at all, e.g. insects.
So there may be some disjunct between what various folks here actually mean by the term "altruism". But conscious (moral) altruism is as easily explained by Darwinian theory as any other sort. The fact that cognition is layered over it really doesn't change anything. More on this later....
Some examples of altruism in the animal kingdom which, from a biological point of view, qualify.
Stanford said:
Altruistic behaviour is common throughout the animal kingdom, particularly in species with complex social structures. For example, vampire bats regularly regurgitate blood and donate it to other members of their group who have failed to feed that night, ensuring they do not starve. In numerous bird species, a breeding pair receives help in raising its young from other ‘helper’ birds, who protect the nest from predators and help to feed the fledglings. Vervet monkeys give alarm calls to warn fellow monkeys of the presence of predators, even though in doing so they attract attention to themselves, increasing their personal chance of being attacked. In social insect colonies (ants, wasps, bees and termites), sterile workers devote their whole lives to caring for the queen, constructing and protecting the nest, foraging for food, and tending the larvae. Such behaviour is maximally altruistic: sterile workers obviously do not leave any offspring of their own -- so have personal fitness of zero -- but their actions greatly assist the reproductive efforts of the queen.
From a Darwinian viewpoint, the existence of altruism in nature is at first sight puzzling, as Darwin himself realized. Natural selection leads us to expect animals to behave in ways that increase their own chances of survival and reproduction, not those of others. But by behaving altruistically an animal reduces its own fitness, so should be at a selective disadvantage vis-à-vis one which behaves selfishly. To see this, imagine that some members of a group of Vervet monkeys give alarm calls when they see predators, but others do not. Other things being equal, the latter will have an advantage. By selfishly refusing to give an alarm call, a monkey can reduce the chance that it will itself be attacked, while at the same time benefiting from the alarm calls of others.
So, how do we get past this "at first sight puzzling" fact of altruism? This was something that Darwin himself considered.
(Emphasis mine)
Stanford said:
The problem of altruism is intimately connected with questions about the level at which natural selection acts. If selection acts exclusively at the individual level, favouring some individual organisms over others, then altruism cannot evolve, for behaving altruistically is disadvantageous for the individual organism itself, by definition. However, it is possible that altruism may be advantageous at the group level. A group containing lots of altruists, each ready to subordinate their own selfish interests for the greater good of the group, may well have a survival advantage over a group composed mainly or exclusively of selfish organisms. A process of between-group selection may thus allow the altruistic behaviour to evolve. Within each group, altruists will be at a selective disadvantage relative to their selfish colleagues, but the fitness of the group as a whole will be enhanced by the presence of altruists. Groups composed only or mainly of selfish organisms go extinct, leaving behind groups containing altruists. In the example of the Vervet monkeys, a group containing a high proportion of alarm-calling monkeys will have a survival advantage over a group containing a lower proportion. So conceivably, the alarm-calling behaviour may evolve by between-group selection, even though within each group, individual selection favours monkeys that do not give alarm calls.
The idea that group selection might explain the evolution of altruism was first broached by Darwin himself. In The Descent of Man (1871), Darwin discussed the origin of altruistic and self-sacrificial behaviour among humans. Such behaviour is obviously disadvantageous at the individual level, as Darwin realized: “he who was ready to sacrifice his life, as many a savage has been, rather than betray his comrades, would often leave no offspring to inherit his noble nature” (p.163). Darwin then argued that self-sarcrificial behaviour, though disadvantageous for the individual ‘savage’, might be beneficial at the group level: “a tribe including many members who...were always ready to give aid to each other and sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection” (p.166). Darwin's suggestion is that the altruistic behaviour in question may have evolved by a process of between-group selection.
The article considers this issue in greater depth, then moves on to the question of what the OP might call "moral" rather than biological altruism, that is, altruism that is voluntary and neither reciprocal nor beneficial to kin:
Standford said:
If by ‘real’ altruism we mean altruism done with the conscious intention to help, then the vast majority of living creatures are not capable of ‘real’ altruism nor therefore of ‘real’ selfishness either. Ants and termites, for example, presumably do not have conscious intentions, hence their behaviour cannot be done with the intention of promoting their own self-interest, nor the interests of others. Thus... the contrast between ‘real’ altruism and merely apparent altruism simply does not apply to most animal species....
Human behaviour is obviously influenced by culture to a far greater extent than that of other animals, and is often the product of conscious beliefs and desires (though this does not necessarily mean that genetics has no influence).... Numerous human behaviours seem anomalous from the evolutionary point of view. Think for example of adoption. Parents who adopt children instead of having their own reduce their biological fitness, obviously, so adoption is an altruistic behaviour. But it is does not benefit kin -- for parents are generally unrelated to the infants they adopt -- and nor do the parents stand to gain much in the form of reciprocal benefits. So although kin selection and reciprocal altruism may help us understand some human behaviours, they certainly cannot be applied across the board.
Where human behaviour is concerned, the distinction between biological altruism, defined in terms of fitness consequences, and ‘real’ altruism, defined in terms of the agent's conscious intentions to help others, does make sense. (Sometimes the label ‘psychological altruism’ is used instead of ‘real’ altruism.) ....
Elliott Sober (1994) argues that, even if we accept an evolutionary approach to human behaviour, there is no particular reason to think that evolution would have made humans into egoists rather than psychological altruists. On the contrary, it is quite possible that natural selection would have favoured humans who genuinely do care about helping others, i.e. who are capable of ‘real’ or psychological altruism. Suppose there is an evolutionary advantage associated with taking good care of one's children -- a quite plausible idea. Then, parents who really do care about their childrens' welfare, i.e. who are ‘real’ altruists, will have a higher inclusive fitness, hence spread more of their genes, than parents who only pretend to care, or who do not care. Therefore, evolution may well lead ‘real’ or psychological altruism to evolve. Contrary to what is often thought, an evolutionary approach to human behaviour does not imply that humans are likely to be motivated by self-interest alone. One strategy by which ‘selfish genes’ may increase their future representation is by causing humans to be non-selfish, in the psychological sense.
I would add 2 more points.
First, in a highly social species like humans, in which many unrelated family groups share common resources, a tendency toward generalized altruism, especially toward children and pregnant women, has a selective advantage. Of course, this tendency is counterbalanced by other non-altruistic selectors, so we don't get pure altruism in humans.
Studies do show that most humans (John Gacey and Dean Corll would be notable exceptions) have a generally protective reaction to children. In fact, we have a generally positive and protective reaction toward anything that has physical features typical of small children.
Second, we must be careful to distinguish why a behavioral trait would be selected for (the evolutionary reason for a behavior's existence) and why the individual performs the behavior (the psychological reason for engaging in the behavior). These are not one and the same, but are often confused in discussions of the evolution of behavior.
As Dennett or Pinker put it (I can't recall which at the moment).... Why does a cat lick itself? Because it enjoys it. Why should there exist cats who enjoy licking themselves? Because the grooming has a selective advantage.
Same for fish who allow other cleaner-fish to groom them. Experiments have shown that these fish don't care about the cleaning, and likely aren't aware of it at all. They just like the tickling. But fish-who-enjoy-tickling evolved because of selective pressure involving the benefits of grooming.
So, the man who dives into the icy water to save some strangers' kids -- there's an evolutionary reason why he would feel the impulse to help these kids at the risk of his own life, but he need not be aware of it.
Ditto for donating to charity, stopping to help a stranded motorist change a tire, or sharing your oxygen with a fellow miner trapped in a shaft. We do it (as Dustin explained in post 4) because we feel bad if we don't. And we feel bad if we don't because our evolutionary past selected for that feeling.
