1 Such organisms need not be deemed to be making conscious decisions, of course, but the rationality, such as it is, of the "decisions" they make is typically anchored to the expected benefit to the individual organism. See Sober and Wilson (1998) for important discussions of gene, individual, and group benefits of such decision-making.
2 Sober and Wilson (1998) note that there is a gap in their model of cultural evolution: "We can say that functionless [relative to human individual and group fitness] behavior should be more common in humans than other species, but we cannot explain why a particular functionless behavior has evolved in a particular culture. That kind of understanding probably requires detailed historical knowledge of the culture, and it may turn out that some behaviors evolved mainly by chance." p171. Dawkins' theory of memes, as briefly sketched in a single chapter of The Selfish Gene (1976, but see also Dawkins, 1993), is hardly a theory at all, especially compared to the models of cultural evolution developed by other biologists, such as Cavalli-Sforza and Feldman (1981), Lumsden and Wilson (1981), and Boyd and Richerson (1985). Unlike these others, Dawkins offers no formal development, no mathematical models, no quantitative predictions, no systematic survey of relevant empirical findings. But Dawkins does present an idea that is overlooked by all the others, including Sober and Wilson in this passage, and it is, I think, a most important idea. It is the key to understanding how we can be not just guardians and transmitters of culture, but cultural entities ourselves all the way in.
3 Strictly speaking, to the reproductive prospects of the fluke's genes (or the fluke's "group"'s genes), for as Sober and Wilson (1998) point out (p18) in their use of D. dendriticum as an example of altruistic behavior, the fluke that actually does the driving in the brain is a sort of kamikaze pilot, who dies without any chance of passing on its own genes, benefiting its [asexually reproduced] near-clones in other parts of the ant.
4 Boyd and Richerson (1992) show that "Virtually any behavior can become stable within a social group if it is sufficiently buttressed by social norms." (Sober and Wilson, 1998, p.152) Our biology strongly biases us to value health, nutritious food, the avoidance of bodily injury, and of course having lots of offspring, so a sheltered theorist might suppose that it is highly unlikely that any human group could ever support a fashion for, say, bodily fragility or bulimia, or the piercing of bodily parts or, or suicide, or celibacy. If even these practices can so readily overturn our innate biases, where can Wilson's leash do any serious constraining?
5 "What benefit could there be to diverting time and energy to the making of plinking noises, or to feeling sad when no one has died? . . . .As far as biological cause and effect are concerned, music is useless." (p528) On p538, he contrasts music with the other topics of his book: "I chose them as topics because they show the clearest signs of being adaptations. I chose music because it shows the clearest signs of not being one."
6 This is not the decisive difference some critics of memes have declared. We can readily enough imagine virus-like symbionts that have alternate transmission media that are (roughly) indifferent to whether they arrive at new hosts by direct transportation (as with regular bacteria, viruses, viroids, fungi . . . ) or by something akin to the messenger-RNA transcription process: they stay in their original hosts, but imprint their information on some messenger element (rather like a prion, we may imagine) that then is broadcast, only to get transcribed in the host into a copy of the "sender." And if there could be two such communication channels, there could be twelve or a hundred, just as there are for transmission of cultural habits.
7 Sober and Wilson (1998) describe circumstances in which individuals of unrelated lineages thrown into group situations can be selected for cooperativity. Just how if at all this model can be adapted for memic coalescence is a topic for further research.