Posted: 19 Jan 2010 10:29 AM PST
Social butterflies who shine at parties may get their edge from special genes that make them experts at recognizing faces. Scientists have found the strongest evidence to date that genes govern how well we keep track of who's who.
The findings suggest that face-recognition and other cognitive skills may beseparate fromeach other, and independent of general intelligence. This could help explain what makes one person good at math but bad at music, or good at spatial navigation but bad at language
"People have wondered for a long time what makes one person cognitively different from another person," said cognitive psychologist Nancy Kanwisher ofMIT, coauthor of thestudy published Jan. 7 in Current Biology. "Our study is one tiny piece of the answer to this question."
The ability to recognize faces is not just handy for cocktail parties, it's crucial for distinguishing friend from foe and facilitating social interactions. If face recognition increases our ability to fend off predators and find mates,there is an evolutionary drive to encode this ability in our genes.
To test this, Kanwisher's team looked at whether the ability to recognize faces runs in the family. They found that identical twins, who share 100 percentof their genes, were more similar in their face-recognition ability than fraternal twins, who share only 50 percentof their genes. This suggests the ability to recognize faces is heritable.
"This is the strongest evidence for a role of genes in face recognition abilities in humans," Kanwisher said.
Some scientistshave proposedthat IQ is a general factor: You are either smart at all mental abilities or weak across mental abilities. Others havesuggested that each mental ability has its ownseparate hardware in the brain. The current results show that the latter is true, at least for face recognition.
"There's an ongoing debate about whether the brain is divided into separate pieces that do completely independent things, or whether it's a general-purpose device," said psychologist Gary Marcus ofNew York University, who was not involved in the study. "This is some of the best evidence that genes could target a particular aspect of the mind."
It's unclear how the genes affect recognition, Swisher said.Oneoption is that they determine how well you measure distances between the eyes and mouth. Another possibility is that the genes may make you more extraverted, and spending more time with people helps you get better at recognizing faces.
"We just can't tell which is true," Kanwisher said. "Our study shows that genes exert a specific influence on face recognition ability, but it does tell us which genes are involved, or how exactly they shape the relevant neural circuits."
Though the new findings suggest thatadditional cognitive skillscould berooted in an independant set of genes as well,it maynot be true forabilities. Language, for instance, evolved much later than face perception.
"This may mean that language depends less on genes that evolved specifically for language, and that it's less separable from other aspects of the mind," Marcus said.
Kanwisher and the study's senior author, Jia Liu of Beijing Normal University, are planning future studies to examine the role of genes in language, spatial ability, math and a range of cognitive abilities.
Posted: 18 Jan 2010 09:00 PM PST
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Floating sea ice covers about 11 million square miles of Earth's oceans in the Arctic and Antarctic regions. It plays an importantrole in regulating climate and is critical for many animals. Glaciers and Ice sheets cover around 10 percent of the land area on Earth. Every continent except Australia is partially covered in ice.
Despite its extent and importance, thenature of the cryosphere makes it difficult to visit, study and understand. Because of the remote and harsh conditions throughout most of the polar regions, scientists who study them often have to rely on data collected from spacefor research.
The images taken by satellites and astronauts provide critical information forunderstanding the rapidly changing climate near the poles, but they also deliver some surprisingly beautiful, strange and intriguing images. We've collected some of the best here.
Above: The Wilkins ice shelf on the Antarctic Peninsula dramatically broke apart in February 2008. In the image above, captured by the Taiwanese satellite Formosat-2, big pieces of the ice shelf float in a frozen matrix of smaller bits of ice. Some of the larger chunks are several hundred yards long. The image was made from near-infrared, infrared and green wavelengths reflected by the ice.
Below: This image from NASA's Terra satellite, taken in November 2009, gives a wider view of the event.
Click on any image in this gallery for a higher-resolution version.
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