The Meme Machine

80 THE MEME MACHINE
tune quickly. Or if females (for whatever reason) start going for ritualised
hunting dances then it becomes advantageous to have male children who can
copy dances. The selection pressures on the genes now change in the wake of
changes in the memes. The process of sexual selection is exactly the same as it
is in examples of biological evolution, but with the added twist that the things
being selected for can spread at the speed of memetic evolution. Meme-driven
sexual selection will favour mating with males who are not only good at
imitating in general, but who are good at imitating whatever happen to be the
favoured memes at the time. In this way the memes are, as it were, dragging the
genes along. The leash has been reversed and, to mix metaphors, the dog is in
the driving seat.
Please note, however, that sexual selection is not necessary for a memetic
explanation of brain size, and its role must be an empirical question for the
future. The first three processes alone will produce the selection pressures
required to drive a runaway increase in brain size – if one further small
assumption is made. That is, that being good at imitation requires a big brain.
Interestingly, there has been so little attention paid to imitation that there is very
little information to back this up. However, this theory suggests that the main
tasks of our larger brains are first, the general ability to imitate, and second, the
particular ability to imitate the kinds of memes that have proliferated in our
species’ past.
Can this theory be tested? Like so many biological theories it is not easy to
devise specific experimental tests. Nevertheless, some predictions can be made.
For example, within any related group of species I would predict that imitation
ability will correlate positively with brain size. That is, the best imitators will
have the largest brains. Given the scarcity of imitation among other animals
there will not be much data to choose from, and there will be problems with
choosing an appropriate measure of encephalisation, but this study ought to be
possible for various groups of birds and cetaceans.
Using humans, experiments could compare two people performing the same
actions but with one person initiating the action while the other imitates it.
Various measures could be used to determine just how much extra demand is
created by imitating. For example, cognitive studies should show that imitation
requires a lot of processing and that we have specialised mechanisms for doing
it. Brain-scan studies should show that imitation requires a large amount of
energy, and that the extra activity is found predominantly in the evolutionarily
newer parts of the brain – those parts that differentiate us from other species. I
would not be surprised if specific neurons were found that carry out some of the