Peter Richerson uses part of his presentation there to describe his resistance to the "meme" terminology:
In this exercise, we think it best to wear the analogy between genes and memes most lightly. For example, we have resisted using the term “meme” to describe the “unit” of cultural transmission. who knows if the structure of cultural inheritance is anything like the neatly particulate gene?So, the idea is that memes are like genes in that they transmit heritable material from one generation to the next, they undergo drift, they recombine, they mutate, they are subject to selection, they engage in hitchhiking, they sometimes have associated phemes - and the ones that do evolve more slowly - and they evolve via Darwinian evolution. They are not necessarily like genes in every single way!
As for DNA genes being "neatly particulate", that is a highly dubious idea. DNA genes can be sliced and diced during meiosis every which way and can be modulated by methylation and by chromatin remodeling caused by post-translational modification of histone proteins. They are just not all that particulate. Even if they were: so what? Memes do not have to be like genes in every single way!
Internet memes have pretty neatly discrete and digital representations. I expect the earliest genes were less "neatly particulate" than modern ones are, through having poorer quality error correction and more analog noise. So: on closer inspection, the resemblance between the cultural and organic realms deepens.
Peter goes on to say:
We do know that culture is most ungene-like in many respects. Culture has the principle of inheritance of acquired variation (what one person invents another can imitate). we are not necessarily blind victims of chance imitation, but can pick and choose among any cultural variants that come to our attention and creatively put our own twist on them. we don’t have to imitate our parents or any other specific individuals but can always be open to a better idea, or own invention or someone else’s.Acquired variation of a type broadly similar to what Peter mentions can be inherited in the organic realm too - as when a dog gets fleas and then passes them on to their offspring.
Humans can pick and choose the diseases they acquire - to some extent - as well as the ideas they acquire. Both realms have vaccination, immune systems, disease resistance and disease avoidance. Not so much of a difference there, it seems.
We don't have to have the same food symbionts as our parents. If a new foodstuff comes along we can form a symbiosis with that foodstuff instead. Other creatures have similar food symbioses - for example ants.
So, the differences Peter mentions are mostly exaggerated. Not that there are no differences - just that the similarities overwhelm them, abundantly justifying the meme-gene association.
If you understand that memes are the heritable material of cultural symbionts, you get to reuse all the standard mathematical models of symbiosis in biology - whereas if you don't you have to invent a whole bunch of new models - which is a big waste of time.
Will more of the people in academia someday "get" these kinds of relationship? Their persistent failure to do so just makes them look as though they don't properly understand their own subject to the memeticists. Is there some good reason why we can't we all get onto the same page on this issue? If so, what is it?