We will settle here for one detailed illustration of one way in which biological altruism can be given an evolutionary explanation, followed by a sketch of the ways in which this and other evolutionary mechanisms might likewise explain the emergence of psychological altruism—keeping in mind that this is all just one part of explaining morality proper,
The very idea that biological altruism can come about through natural selection may initially seem puzzling. One way of characterizing natural selection, after all, is in terms of “selfish genes”: natural selection occurs when a variant of a gene (an allele) at a given locus tends to cause a modification of a bodily or behavioral trait (a phenotypic trait) in a way that, in the overall environment, tends to cause that variant of the gene to increase its relative frequency in the next generation; this then increases the representation of the associated trait modification as well.
Typically this happens when the phenotypic modification is one that causes the organism to have greater reproductive success: if, in the overall context, allele A causes its carrier to have a trait T that causes the organism to have more offspring than other organisms in the population who carry rival allele A* and display alternative trait T*, then A will be inherited and carried by more organisms in succeeding generations; and that means that T will likewise be displayed by more organisms (Dawkins, 1989).
But how do we get from “selfish genes” increasing their representation in the gene pool, via improving the reproductive success of their carriers, to such things as cooperation and biological altruism? It turns out there are many ways.
To take one dramatic example, consider social insect colonies, and in particular, the Hymenoptera (bees, ants and wasps). In these colonies we find such an extreme degree of cooperation—division of labor (queen, workers, soldiers, etc.), food-sharing, information sharing—that it is tempting to view the entire colony as a single functioning organism. Indeed, in the case of stinging worker honey bees, there is not only cooperative labor but also, when necessary, the ultimate sacrifice in defense of the hive (at least where the invader is a mammal, stinging of which proves fatal to the bee as the barbed sting is torn out upon being deposited in the victim). How can such striking cooperation and self-sacrifice be explained in evolutionary terms?
This mechanism of “kin selection” can explain how worker bees evolved such apparently ‘selfless’ traits, focused on aiding the queen's survival and reproduction. In fact, the situation is even more interesting and extreme: workers have evolved to serve the queen's reproduction at the complete expense of their own, as they are sterile
The crucial point is just that any kind of genetically-based trait can evolve if it happens to have the right kind of feedback effect on the genes that influence it. This brings us, then, to the sort of trait we are more interested in: a disposition for psychological altruism.
For example, suppose you receive a letter from UNICEF soliciting contributions for health and nutrition programs for children in Darfur, and you are moved to send a check. This is not merely selective altruism toward kin or likely reciprocators, but altruism toward strangers who are in no position to reciprocate, and it might therefore seem puzzling from a purely biological point of view: such ‘indiscriminate altruism’ isn't biologically adaptive in the way more selective altruism might be; your helping children in Darfur isn't helping to propagate your own genes, so it may seem mysterious how such a trait could have evolved through natural selection. But a trait that is not presently adaptive may once have been. In the environment in which our hominin ancestors lived, where there was little positive contact with outsiders, even relatively indiscriminate altruism would tend to benefit kin or potential reciprocators, and so might have been a simple adaptive mechanism on the whole.
The very idea that biological altruism can come about through natural selection may initially seem puzzling. One way of characterizing natural selection, after all, is in terms of “selfish genes”: natural selection occurs when a variant of a gene (an allele) at a given locus tends to cause a modification of a bodily or behavioral trait (a phenotypic trait) in a way that, in the overall environment, tends to cause that variant of the gene to increase its relative frequency in the next generation; this then increases the representation of the associated trait modification as well.
Typically this happens when the phenotypic modification is one that causes the organism to have greater reproductive success: if, in the overall context, allele A causes its carrier to have a trait T that causes the organism to have more offspring than other organisms in the population who carry rival allele A* and display alternative trait T*, then A will be inherited and carried by more organisms in succeeding generations; and that means that T will likewise be displayed by more organisms (Dawkins, 1989).
But how do we get from “selfish genes” increasing their representation in the gene pool, via improving the reproductive success of their carriers, to such things as cooperation and biological altruism? It turns out there are many ways.
To take one dramatic example, consider social insect colonies, and in particular, the Hymenoptera (bees, ants and wasps). In these colonies we find such an extreme degree of cooperation—division of labor (queen, workers, soldiers, etc.), food-sharing, information sharing—that it is tempting to view the entire colony as a single functioning organism. Indeed, in the case of stinging worker honey bees, there is not only cooperative labor but also, when necessary, the ultimate sacrifice in defense of the hive (at least where the invader is a mammal, stinging of which proves fatal to the bee as the barbed sting is torn out upon being deposited in the victim). How can such striking cooperation and self-sacrifice be explained in evolutionary terms?
This mechanism of “kin selection” can explain how worker bees evolved such apparently ‘selfless’ traits, focused on aiding the queen's survival and reproduction. In fact, the situation is even more interesting and extreme: workers have evolved to serve the queen's reproduction at the complete expense of their own, as they are sterile
The crucial point is just that any kind of genetically-based trait can evolve if it happens to have the right kind of feedback effect on the genes that influence it. This brings us, then, to the sort of trait we are more interested in: a disposition for psychological altruism.
For example, suppose you receive a letter from UNICEF soliciting contributions for health and nutrition programs for children in Darfur, and you are moved to send a check. This is not merely selective altruism toward kin or likely reciprocators, but altruism toward strangers who are in no position to reciprocate, and it might therefore seem puzzling from a purely biological point of view: such ‘indiscriminate altruism’ isn't biologically adaptive in the way more selective altruism might be; your helping children in Darfur isn't helping to propagate your own genes, so it may seem mysterious how such a trait could have evolved through natural selection. But a trait that is not presently adaptive may once have been. In the environment in which our hominin ancestors lived, where there was little positive contact with outsiders, even relatively indiscriminate altruism would tend to benefit kin or potential reciprocators, and so might have been a simple adaptive mechanism on the whole.
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