[kaon_2]

I once read a fascinating booklet that made the argument that "intelligence" as we call it evolved out of the ability to track better. Early hominids had many different skills, but improved reasoning capability paid for itself evolutionary speaking by making you a much better tracker. You spot measure the temperature of droppings, and reason that a gazelle was here only 2 hours ago. You see the tracks and notice that the gazelle was probably in the shade to avoid the midday sun. Now it must be thirsty and is therefore likely to go visit the stream nearby.

In that context, "Intelligence" is just one part of a collection of useful skills for a band of early hominids. You only need a few great trackers, but those trackers would be grateful if they also had some "meatheads" in the crew that are phenomenally atletic. And who knows; early hominids would mock each other for not being good at tracking, but would they call each other dumb? I somehow doubt it.