White American Skulls Bigger Now Than Before

We might not be necessarily smarter, but it looks like our heads are getting bigger. Scientists who studied white Americans' skulls from the mid-1800's to the 1980's have found that white Americans have larger skulls with space enough to accommodate a tennis ball's worth of extra brain matter.

Still, the researchers are not able to pinpoint a the reason behind this.

"The varieties of changes that have swept American life make determining an exact cause an endlessly complicated proposition," said researcher Lee Jantz, coordinator of the University of Tenessee's Forensic Anthropology Center . "It likely results from modified growth patterns because of better nutrition, lower infant and maternal mortality, less physical work, and a breakdown of former ethnic barriers to marriage. Which of these is paramount we do not know."

Based on the skulls they studied, the researchers determined that the skulls have gotten narrower, larger, and taller.Skull height has increased by 6.8 percent since the 1800's, while body height has increased by 5.6 percent. Skull dimensions have continued to change while body height has pretty much plateaued.

Human skulls continued to grow until around 30,000 years ago. Then, around five to six thousand years ago, they shrank. Scientists don't know exactly why, but one theory explains that as agriculture made our lives easier, we did not need the extra brain space.

"Americans drive cars, vaccinate their children-and an excess of food is now a bigger problem than undernutrition, among many other things. It's almost as if we're conducting an experiment on ourselves to see how we'll respond to a totally new environment," said Jantz.