Human intelligence is declining according to Stanford geneticist.  Dr. Gerald Crabtree explains that of the roughly 5,000 genes he considered the basis for human intelligence, a number of mutations over the years has forced modern man to be only a portion as bright as his ancestors.

I would wager that if an average citizen from Athens of 1000 BC were to appear suddenly among us, he or she would be among the brightest and most intellectually alive of our colleagues and companions, with a good memory, a broad range of ideas, and a clear-sighted view of important issues. … The basis for my wager comes from new developments in genetics, anthropology, and neurobiology that make a clear prediction that our intellectual and emotional abilities are genetically surprisingly fragile.

According to the doctor, humans were at their most intelligent when “every individual was exposed to nature’s raw selective mechanisms on a daily basis.”

“We, as a species, are surprisingly intellectually fragile and perhaps reached a peak 2,000 to 6,000 years ago,” he writes. “If selection is only slightly relaxed, one would still conclude that nearly all of us are compromised compared to our ancient ancestors of 3,000 to 6,000 years ago.”

That doesn’t mean it’s all downhill, though. Dr. Crabtree says,

Although our genomes are fragile, our society is robust almost entirely by virtue of education, which allow strengths to be rapidly distributed to all members.