Considering all the scientific advancements of the modern age – putting a man on the moon, inventing nuclear energy and creating the Internet, just to mention a few – it seems ludicrous to argue that human beings are getting dumber.
Yet that's exactly what Stanford University researcher Gerald Crabtree suggests is happening in a set of papers, published in the journal Trends in Genetics.
Crabtree suggests our intellectual and emotional abilities peaked before our early ancestors began leaving Africa, which occurred some two million years ago. At the time, he argues, intelligence was critical for survival, and thus, under selective pressure, early humans evolved to have genes that maximized brain power.
"The development of our intellectual abilities and the optimization of thousands of intelligence genes probably occurred in relatively non-verbal, dispersed groups of peoples before our ancestors emerged from Africa," Crabtree said in a press release.
Ever since, human intellect has been on the decline, he says, because the advent of agriculture and urbanization has lessened the selective pressure to weed out genetic mutations that hamper intelligence.
"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," Crabtree said in his paper, according to The Independent.
"Furthermore, I would guess that he or she would be among the most emotionally stable of our friends and colleagues."
It's probably no surprise that Crabtree's conclusions are hotly debated.
Although we can't blame it on genetics, however, there is perhaps a case to be made that new technologies let us get away with using less brain power. Think back to how many telephone numbers you used to know by heart before the invention of the memory-dial function and contact lists on our mobile phones. Consider how you were forced to creatively solve problems and come up with answers to questions before Google.
Are we really getting dumber?