Wild rabbit brain and modern human brain

"The brains of rabbits raised in hutches are 15-30% smaller than in wild rabbits that develop their wits and skills " 
Charles Darwin, 1871

http://discovermagazine.com/2010/sep/25-modern-humans-smart-why-brain-shrinking#.Ux8YZuddXWY


http://phys.org/news/2011-06-farming-blame-size-brains.html

"Looking at human fossil evidence for the past 200,000 years, Lahr looked at the size and structure of the bones and skulls found across Europe, Africa and Asia. What they discovered was that the largest Homo sapiens lived 20,000 to 30,000 years ago with an average weight between 176 and 188 pounds and a brain size of 1,500 cubic centimeters.

They discovered that some 10,000 years ago however, size started getting smaller both in stature and in brain size. Within the last 10 years, the average human size has changed to a weight between 154 and 176 pounds and a brain size of 1,350 cubic centimeters.

While large size remained static for close to 200,000 years, researchers believe the reduction in stature can be connected to a change from the hunter-gatherer way of life to that of agriculture which began some 9,000 years ago."

http://ajcn.nutrition.org/content/71/3/665.full.pdf+html

And the very good letter of my friend S Cunnane

http://ajcn.nutrition.org/content/72/6/1584.2.full.pdf+html