The brain did not evolve over millions of years to spend its free time practicing something irrelevant to our lives. Indeed, the discovery that the brain is constantly practicing something suggests that evolution has, in a sense, made a bet about the value of that particular thing.

Reference: Social: Why Our Brains are Wired to Connect; A book by Matthew D. Lieberman


Does "made a bet" here mean speculate (v.) or conjecture (v.)?

Thank you.

Bahareh MDoes "made a bet" here mean speculate (v.) or conjecture (v.)?

Yes, more or less. Evolution has guessed or supposed that the thing in question is important. A correct supposition will be beneficial and vice versa (like winning or losing a bet).