If Modern Humans Are So Smart, Why Are Our Brains Shrinking?

[Warpy]

8. It probably had to be bigger due to the physical stress

of living a nomadic lifestyle, following and chasing game and needing to know where and when edible plants would ripen.

My guess is that the major shrinkage occurred with the invention of agriculture and the more sedentary lifestyle of raising and harvesting crops. Concurrently, the variety of foodstuffs decreased sharply as people only grew what gave them the biggest caloric return for calories expended in farming.

However, a gradual dumbing down also makes some sense as a devolutionary force that might keep us from blowing up the planet.

One thing should be pointed out, though: it's not the size of the brain but the number and depth of convolutions on its surface that give us the most brain power. This is why the "women have smaller brains, must be dumber" guys are all wrong.