The geneticist, Gerald Crabtree, has published two journal articles on this hypothesis. According to the publication PopSci, Crabtree argues that “human intelligence may have actually peaked before our ancient predecessors ever left Africa...Genetic mutations during the past several millennia are causing a decline in overall human intellectual and emotional fitness...Evolutionary pressure no longer favors intellect, so the problem is getting exponentially worse.” Crabtree argues that this process, like other evolutionary processes, take a long time to emerge.

Crabtree’s central thesis to back his claim up is, according to PopSci , that “each generation produces deleterious mutations, so down the line of human history, our intelligence is ever more impaired compared to that of our predecessors.”

Continue Reading...