"For a long time, we were pretty dumb. Humans did little but make "the same very boring stone tools for almost 2 million years," he said. Then, only about 150,000 years ago, a different type of spurt happened - our big brains suddenly got smart. We started innovating. We tried different materials, such as bone, and invented many new tools, including needles for beadwork. Responding to, presumably, our first abstract thoughts, we started creating art and maybe even religion.
"To understand what caused the cognitive spurt, Khaitovich and colleagues examined chemical brain processes known to have changed in the past 200,000 years. Comparing apes and humans, they found the most robust differences were for processes involved in energy metabolism.
The finding suggests that increased access to calories spurred our cognitive advances, said Khaitovich, carefully adding that definitive claims of causation are premature.
The research is detailed in the August 2008 issue of Genome Biology.
The extra calories may not have come from more food, but rather from the emergence of pre-historic "Iron Chefs;" the first hearths also arose about 200,000 years ago.
While other theories for the brain's cognitive spurt have not been ruled out (one involves the introduction of fish to the human diet), the finding sheds light on what made us, as Khaitovich put it, "so strange compared to other animals." - More