Smaller Brains, Smarter Humans

Over the last 30,000 years, the human brain has decreased about 10% in size. But our brains are not just getting smaller—they are also getting more efficient.

Based on skulls found in Europe, Asia, and the Middle East, the human brain was about 1,500 cubic centimeters 30,000 years ago, and now it's down to about 1,359 cubic centimeters. That means that, as a species, humans now only need 90% the brain size that we did 30,000 years ago. That's an incredibly rapid change—30 millennia is practically no time at all in evolutionary terms—and one for which anthropologists have plenty of explanations. First up, there's the physiological answer. It's easy to equate brain size with cognitive ability, but it's only part of the story.

NASA astronomer Michelle Thaller on ​the multiple dimensions of space and human sexuality

Science and the squishiness of the human mind. The joys of wearing whatever the hell you want, and so much more.

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How to split the USA into two countries: Red and Blue

Progressive America would be half as big, but twice as populated as its conservative twin.

Image: Dicken Schrader
Strange Maps
  • America's two political tribes have consolidated into 'red' and 'blue' nations, with seemingly irreconcilable differences.
  • Perhaps the best way to stop the infighting is to go for a divorce and give the two nations a country each
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Ideology drives us apart. Neuroscience can bring us back together.

A guide to making difficult conversations possible—and peaceful—in an increasingly polarized nation.

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  • How can we reach out to people on the other side of the divide? Get to know the other person as a human being before you get to know them as a set of tribal political beliefs, says Sarah Ruger. Don't launch straight into the difficult topics—connect on a more basic level first.
  • To bond, use icebreakers backed by neuroscience and psychology: Share a meal, watch some comedy, see awe-inspiring art, go on a tough hike together—sharing tribulation helps break down some of the mental barriers we have between us. Then, get down to talking, putting your humanity before your ideology.
  • The Charles Koch Foundation is committed to understanding what drives intolerance and the best ways to cure it. The foundation supports interdisciplinary research to overcome intolerance, new models for peaceful interactions, and experiments that can heal fractured communities. For more information, visit charleskochfoundation.org/courageous-collaborations.