Human brains have been shrinking since the Stone Age. We don’t know why

stone
Image: Haslemere Educational Museum

It’s something of a well-known secret among anthropologists: Based on measurements of skulls, the average brain volume of Homo sapiens has reportedly decreased by roughly 10 percent in the past 40,000 years. This reduction is a reversal of the trend of cranial expansion, which had been occurring in human evolution for millions of years prior.

Since this pattern was first noticed in the late 1980s, researchers have proposed a number of possible explanations. Some say the decrease came from from a slight reduction in body size and robustness, related to the warmer conditions of the Holocene. Bigger bodies were better during the Ice Age, and then became disadvantageous as the climate warmed. But anthropologist John Hawks has countered this idea by showing that the documented brain reduction is too great to be explained by simply having slightly smaller bodies.

Related article:  Can we boost human memory by tweaking the microbiome?

Other researchers point to the fact that brains are energetically costly organs. Though the modern human brain is only 2 percent of our body weight, it consumes almost one quarter our energy input. By inventing ways to store information externally — cave art, writing, digital media — humans were able to shed some brain bulk, according to one proposal.

Read full, original post: The Human Brain Has been Getting Smaller Since the Stone Age

Outbreak
Outbreak Daily Digest
Biotech Facts & Fallacies
Talking Biotech
Genetics Unzipped
ft covidresponseus feature

Video: Viewpoint: The US wrote the global playbook on the coronavirus and then ignored it

A year ago, the United States was regarded as the country best prepared for a pandemic. Our government had spent ...
mag insects image superjumbo v

Disaster interrupted: Which farming system better preserves insect populations: Organic or conventional?

A three-year run of fragmentary Armageddon-like studies had primed the journalism pumps and settled the media framing about the future ...
dead bee desolate city

Are we facing an ‘Insect Apocalypse’ caused by ‘intensive, industrial’ farming and agricultural chemicals? The media say yes; Science says ‘no’

The media call it the “Insect Apocalypse”. In the past three years, the phrase has become an accepted truth of ...
globalmethanebudget globalcarbonproject cropped x

Infographic: Cows cause climate change? Agriculture scientist says ‘belching bovines’ get too much blame

A recent interview by Caroline Stocks, a UK journalist who writes about food, agriculture and the environment, of air quality ...
organic hillside sweet corn x

Organic v conventional using GMOs: Which is the more sustainable farming?

Many consumers spend more for organic food to avoid genetically modified products in part because they believe that “industrial agriculture” ...
benjamin franklin x

Are most GMO safety studies funded by industry?

The assertion that biotech companies do the research and the government just signs off on it is false ...
gmo corn field x

Do GMO Bt (insect-resistant) crops pose a threat to human health or the environment?

Bt is a bacterium found organically in the soil. It is extremely effective in repelling or killing target insects but ...
favicon

Environmental Working Group: EWG challenges safety of GMOs, food pesticide residues

Known by some as the "Environmental Worrying Group," EWG lobbies for tighter GMO legislation and famously puts out annual "dirty dozen" list of fruits and ...
m hansen

Michael Hansen: Architect of Consumers Union ongoing anti-GMO campaign

Michael K. Hansen (born 1956) is thought by critics to be the prime mover behind the ongoing campaign against agricultural biotechnology at Consumer Reports. He is an ...
News on human & agricultural genetics and biotechnology delivered to your inbox.
Optional. Mail on special occasions.
Send this to a friend