It's all linked to the evolution of intelligence, says author Satoshi Kanazawa, an evolutionary psychologist at the London School of Economics and Political Science.

(Also see "Future Humans: Four Ways We May, or May Not, Evolve.")

Kanazawa's theory is that intelligence—particularly our ability for on-the-spot problem solving and reasoning—arose as an adaptation to deal with the unusual and unexpected, such as a sudden forest fire.

Since disasters like that are rare in daily life, responding to them wouldn't likely be something our ancestors were hard-wired to "know" how to do. Surviving the fire required both the ability to think up a new behavior, and the willingness to try it out.

Passed down