Ya?l: Hey Don, I bet you think you're pretty smart.

Don: Well, uhm, Ya?l, I guess so. I mean, I'm no genius or anything.

Y: Relax. I just meant that you have a big brain compared to most other animals.

D: OK. I guess in that sense I am pretty smart--at least compared to a chimp or something.

Y: But guess what--about ten-thousand years ago there was a race of people who may have been even smarter than we modern humans.

D: Really? Who where they?

Y: They're known as the Boskops because that's the region in South Africa where their  fossils were first found. And the cool thing is that the Boskops appear to have had  skulls that were a lot bigger than ours.

D: Which would mean that their brains were probably bigger than ours, too! But does  that mean they were necessarily smarter?

Y: Well, that's impossible to know for sure. But consider that our bigger brains allow us to imagine possibilities and alternate realities in ways that smaller-brained animals can't, as far as we know. Now, if you imagine a person with a brain significantly  larger than normal, it stands to reason that they'd be able to process more information at once and see and imagine things in ways that are beyond us.

D: That's interesting. But if the Boskops were so smart, where are they now?

Y: They died out, obviously. And that may be simply because their heads were so big that babies heads had a hard time fitting through the birth canal. Maybe too many Boskop babies died in childbirth.

D: So I guess it doesn't always pay to have a big brain.

Y: Maybe not.