There was no longer selection on it; it accumulated
noise and failed to work.
In this case, you can completely eliminate one component,
whereas in the other direction we can push it
to equilibrium, so to speak. With this kind of masking
effect, you can completely eliminate function,
but under these circumstances, these three adaptations
became necessary. When vitamin C availability
dropped down in this model, you had to keep these
up and they increased in their probability in the population
over time. All three of them supported each
other.
I want to make the claim that language and culture
and tools - you put them all together and you
get the ultimate of an artificial niche. I want to claim
that the creation of a symbolic niche recruited this
highly robust, metastable, many-segmented, component
system. Not one mutation, not one place, but
many systems simultaneously drew them together
by virtue of, first of all, the masking effects of culture
that allowed the system to, in effect, accomplish these
things in a variety of social ways. This masked a lot of
other functions, including, I think, a lot of vocalization
functions that we were now being able to carry
on by other means, allowing the release of some of
these functions to be taken up elsewhere. The reason
that we have such a widely distributed and multicomponent
system that has been adapted for language
function is, in part, because it was degenerated then
re-recruited by this process.