Calvi n: I agree that there could be a substantial gap
in there. One of the things that genetic changes do,
even as simple as the one I'm hypothesizing here -
taking the acquisitiveness curve and moving it back
- is make a cultural practice more efficient and more
likely to be reinvented. That is to say: It's sufficiently
strong now that a deaf kid will invent his own sign
language to use with another deaf kid. There are some
instincts now that are serving as backups but they're
very general in how detailed they are.
Maybe there were many attempts to
"take off," so to speak, and so when we
finally see a take-off, we assume that
that was the first take-off.
Varki : Following up on the matter of population,
I think that really is an issue. When we talk about
"human universals" - let's say that music is a human
universal. Well, it's not, in the sense that many people
in the population couldn't carry a tune if they had
to, to save their lives; then there are others who are
Mozarts. It's possible that what happened is that you
had these abilities maybe 150,000 years ago, but as the
population grew and they started bootstrapping this
culture, then maybe that one population got wiped
out. Maybe there were many attempts to "take off," so
to speak, and so when we finally see a take-off, we
assume that that was the first take-off.