A BBC Report shows that people are certainly becoming better at cognitive tests, Average IQ scores are only prevented from rising by resetting the score, so that the Caucasian score is made to average around 100. In fact the tests are getting harder, and people are doing better at them. This gradual upward creep of IQ results is what I understand the Flynn effect to be. Every generation, people get better at doing the cognitive problems that underlie IQ scores.
This effect is experienced across the world, and Third World countries are showing proportionately greater increases in IQ results than in the developed world.
Attempts to explain these results abound: better education, better nutrition, better lighting (seriously) and continuous shift of our work towards cognitively demanding tasks. Whether people are actually becoming more intelligent is not yet clear.
But if the principal task of human existence was to be a good hunter, then tracking, aiming and throwing, and the team cooperation that keeps meat in the pot, would be favoured. It would hardly surprize anyone that, if we had to, overweight bureaucrats and salesmen would get better at hunting than people have to be when food is found in supermarkets.Or those same people get better at war-making when they have been winnowed by three years of combat, as happened in World War 2.
Where I live, Inuit immigrants to Ottawa scavenge liquor and beer bottles for the cash available on bottle returns. These are useful people who might otherwise be beggars. Their grandfathers hunted. The grandsons of the bottle scavengers will live in cities and hold low-level salaried jobs. 10,000 years in five generations. The IQs of the descendants will be higher too. Yet whether the neolithic grandfathers were more or less intelligent than their urban grandsons depends more on the nature of the life-test, than a change in cognitive capacities.
That’s my guess and I am sticking to it.