On many people taking the meme-evolution analogy too far:

The other extension of adaptation is the seemingly innocuous cliché that “cultural evolution has taken over from biological evolution.” […]

Richard Dawkins has drawn the clearest analogy between the selection of genes and the selection of bits of culture, which he dubbed memes. Memes such as tunes, ideas, and stories spread from brain to brain and sometimes mutate in the transmission. New features of a meme that make its recipients more likely to retain and disseminate it, such as being catchy, seductive, funny, or irrefutable, will lead to the meme’s becoming more common in the meme pool. In subsequent rounds of retelling, the most spreadworthy memes will spread the most and will eventually take over the population. Ideas will therefore evolve to become better adapted to spreading themselves. Note that we are talking about ideas evolving to become more spreadable, not people evolving to become more knowledgeable.

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I think you’ll agree that this is not how cultural change works. A complex meme does not arise from retention of copying errors. it arises because some person knuckles down, racks his brain, musters his ingenuity, and composes or writes or paints or invents something. Granted, the fabricator is influenced by ideas in the air, and may polish draft after draft, but neither of these progressions is like natural selection. […] [Draft five and draft six] do not differ by a few random substitution. The value added in each iteration comes from focusing brain-power on improving the product, not from retelling or recopying it hundreds of thousands of times in hope that some malaprops or typos will be useful.

As an aside, I think one of Pinker’s arguments against cultural evolution is unsubstantiated. He claims that one does not “copy” a meme-idea over and over again, waiting for a random mutation to produce a better version; but I argue that when one is faced with a problem that has them stumped, that’s actually exactly what we do. We revisit and pound our minds against the problem, in every direction, in a sense, repeating the problems in our mind over and over again, until suddenly, an anomaly is detected, which usually triggers a torrent of thoughts, and the solution comes to us.

Thus, while I agree with Pinker that the theory of cultural evolution is probably incorrect, I don’t think he use this particularly argument to support his claim.

Stop being so literal-minded! respond the fans of cultural evolution. Of course cultural evolution is not an exact replica of the Darwinian version. In cultural evolution, the mutations are directed and the acquired characteristics are inherited. Lamarck, while being wrong about biological evolution, turned out to be right about cultural evolution.

But this won’t do. Lamarck, recall, was not just unlucky in his guess about life on this planet. As far as explaining complex design goes, his theory was, and is, a non-starter. It is mute about the beneficent force in the universe of all-knowing voice that’s doing all the creative work. To say that cultural evolution is Lamarckian is to confess that one has no idea how it works. […]

Many people unfamiliar with cognitive science see cultural evolution as the only hope for grounding wispy notions like ideas and culture in rigorous evolutionary biology. To bring culture into biology, they reason, one shows how it evolved by its own version of natural selection. But that is a non sequitur; the products of evolution don’t have to look like evolution. The stomach is firmly grounded in biology, but it does not randomly secret variants of acids and enzymes, retain the ones that break down food a bit, let them sexually recombine and reproduce, and so on for hundreds of thousands of meals. Natural selection already went through trial and error in designing the stomach, and now the stomach is an efficient chemical processor, releasing the right acids and enzymes on cue. Likewise, a group of minds does not have to recapitulate the process of natural selection to come up with a good idea. Natural selection designed the mind to be an information processor, and now it perceives, imagines, simulates, and plans. When ideas are passed around, they aren’t merely copied with occasional typographical errors; they are evaluated, discussed, improved on, or rejected. Indeed, a mind that passively accepted ambient memes would be a sitting duck for exploitation by others and would have quickly been selected against.