Human brains have tripled in size over the past 2 million years, growing much faster than those of other mammals.
What might the reasons be for such dramatic brain expansion?
University of Missouri researchers studied three hypotheses for brain growth: ecological demand, social competition and climate change.
Yes, climate change. They're not stupid. An entire presidential cabinet is stuffed with carbon dioxide true believers so it's good diplomacy to at least consider global warming may make us devolve - that would be terrific marketing for a carbon trading scheme. Luckily, the much more likely social competition was determined in their analysis as the major cause of increased cranial capacity.
To test their hypotheses, they collected data from 153 hominid (humans and ancestors) skulls from the past 2 million years. They examined the locations and made a best guess at the global climate changes at the time the fossil was dated, the number of parasites in the region and estimated population density in the areas where the skulls were found.
They determined that population density had the biggest effect on skull size and thus cranial capacity. Sounds vague? Well, there are few rules in psychosocial sciences and a lot of assumptions.
"Our findings suggest brain size increases the most in areas with larger populations and this almost certainly increased the intensity of social competition," said David Geary, Curator's Professor and Thomas Jefferson Professor of Psychosocial Sciences in the MU College of Arts and Science. "When humans had to compete for necessities and social status, which allowed better access to these necessities, bigger brains provided an advantage."
Climate change isn't completely out of the question tangentially, since global climate change and migrations away from the equator resulted in humans becoming better at coping with diverse environments. But the importance of coping with a changing climate was much smaller than the importance of coping with other people.
"Brains are metabolically expensive, meaning they take lots of time and energy to develop and maintain, making it so important to understand why our brains continued to evolve faster than other animals," said Drew Bailey, MU graduate student and co-author of the study. "Our research tells us that competition, whether healthy or not, sets the stage for brain evolution."
Article: "Hominid Brain Evolution," Human Nature, co-authored by Geary and Bailey.
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- What Do EU Countries Give Up When They Opt-out Of GMO Crops? And For Whom?
- Nobel Prize Validates Chinese Medicine? Nope.
- An Easy Problem
- Mother Jones Hates Scientists - And Their Bias Shows
- Machine learning vs NRA, a Grand Challenge
- Thank You Guido
- Hand And Arm Movement To Quadriplegic Patients Restored
- "This is a bit of irony: Mother Jones, which can never be bothered with facts or truth and got sued..."
- "Great piece Steve. While the potential for suffering and death in Africa especially thanks to this..."
- "I look forward to more threats and libel from you in the very near future. It's your stock in trade..."
- "Dear Mr. Campbell: Again you spin and dissemble. It was quite clear from the many tweets between..."
- "One of us does not know what libel means (hint: It is you). Calling me a felon and a fraud is libel..."
- FDA-Approved Test for Meningitis is a Home Run
- Trends In Smoking – Chinese Men In Peril, American Women Get Better Cessation
- Counter-Point: Activists Operate By Outrage, Not Fear
- Whole Foods Recalls Organic Roquefort Cheeses After Listeria Found
- Suicide Tries Linked to Weight-Loss Surgery? Study Doesn’t Show
- Following Rules, Refreezing Thawed Meat is Safe
- Beetles provide clues about the genetic foundations of parenthood
- Trees to power: McMaster engineers build better energy storage device
- High dose chemo & stem cell transplantation results in long-term survival for amyloid patients
- 'Blind analysis' could reduce bias in social sciences papers
- Adoption of streamlined breast cancer treatment has stagnated, study finds