when did it start? Three millennia ago. The human brain was bigger before, but then it started to shrink. Why? A research was devoted to answer this question. Some traces are in an unlikely example: ants.
Fine-tuning brains
Jeremy DeSilva is an anthropologist at Dartmouth College in the United States. He is the one who draws the comparison. What similarity can we have with ants? Some of them practice a form of agriculture, growing mushrooms. And when comparing different ants, those with larger societies have larger brains. Except those that grow mushrooms. Why?
Apparently, a proper division of labor in society would cause brains to shrink. Cognitive abilities are divided and distributed among many members of the group. In other words, intelligence becomes collective. “What if that happened in humans?” says DeSilva.
Human babies are born with an excess of neurons-100 billion. This number decreases as they develop. Brains fine-tune themselves according to the development and environment of the individual.
Mammals evolved in the shadow of dinosaurs. They needed extremely good sensory capabilities to survive. That is why they developed nocturnal habits and night vision. This must have had an impact on neural development.
Modifying environment
The environment put pressure on mammalian brains to develop survival capabilities. Accelerating cognitive progress in a world full of challenges became an advantage.
Birds that colonized oceanic islands had to adapt to unpredictable new territory. They were found to possess larger brains than their continental counterparts. But size is only one piece of the puzzle.
The human brain was bigger before – will it continue to get smaller? Scientists wonder. can that population threshold be reached where information is shared at a level that changes cognitive abilities? We may know in another 3,000 years.
