Random Samples

Science  09 Jun 2006:
Vol. 312, Issue 5779, pp. 1449

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    Brain injuries can destroy the ability to recognize faces, and some people are born without the skill. This condition, known as face blindness or prosopagnosia, was thought to be exceedingly rare, but now a survey of 1600 people has revealed that up to 2% of the population may be afflicted.

    Cognitive neuroscientist Bradley Duchaine of University College London and colleagues used the Internet to recruit participants and conduct a facial recognition survey. The subjects first viewed a face for 3 seconds. They were then presented with three face photos—the original one and two others—and asked to indicate the one they recognized. More difficult tests followed, in which participants were shown larger numbers of faces and asked whether they recognized people in different poses in altered lighting.

    The team, whose research is as yet unpublished, found that dozens of the subjects had serious enough problems with facial recognition that their daily lives would likely be affected. “It's a neglected condition,” says Duchaine. Cognitive neuroscientist Martha Farah of the University of Pennsylvania calls prosopagnosics “the ivory-billed woodpecker of neurological patients: They were rare, and some researchers even doubted that they existed.” Duchaine's team has found some cases in which prosopagnosia seems to run in the family, but the neurological and genetic bases for the condition remain to be unraveled.


    Without the agricultural surpluses made possible by the shift some 10,000 years ago from hunting and gathering to farming, the rise of towns and cities would not have been possible. But a survey of skeletal data from farming sites around the world shows that civilization took a toll on health—especially dental health.

    Anthropologist Clark Larsen of Ohio State University in Columbus reviewed several dozen studies covering hundreds of skeletons from both hunter-gatherer and ancient farming societies. In the June issue of Quaternary International, he reports that farmers' teeth show dramatically increased incidences of cavities compared to hunter-gatherers, probably as a result of eating more carbohydrate-loaded plants and less meat. What's more, a reduction in the size of the face and jaw, from eating softer foods such as cooked porridge, led to crowding of the teeth in the farmers. The shift away from meat eating also led to iron-deficiency anemia, as shown by a pathological increase in bone porosity in the skulls. Higher population densities also took their toll, Clark reports, allowing infectious diseases such as syphilis, tuberculosis, and leprosy—all of which leave telltale marks on the skeleton—to spread much more readily.

    Brian Hayden, an archaeologist at Simon Fraser University in Burnaby, Canada, speculates that the shift to farming also led to psychological stresses from increased population density: “Health took a back seat right from the beginning.”



    The Defense Advanced Research Projects Agency (DARPA) plans to add a “new level of complexity” to next year's Grand Challenge, a contest that pits robot vehicles bristling with radar, cameras, and Global Positioning System antennae against one another over a lengthy course.

    The first two Grand Challenges were desert runs. This time, the autonomous machines will negotiate an urban environment. Their assignment: to safely complete a 93-kilometer simulated military supply mission in under 6 hours, merging with traffic, avoiding obstacles, negotiating busy intersections, obeying traffic signals, executing U-turns, and finding alternate routes when necessary. For traffic, the vehicles will have to contend with one another as well as “teleoperated” ones, says Jan Walker of DARPA.

    Only four vehicles completed last year's Grand Challenge, which was won by “Stanley,” a souped-up Volkswagen Touareg (above) designed by a team at Stanford University. This year, team leader Sebastian Thrun says they're starting with a VW Passat.

    The race, to be run on 3 November 2007, carries a $2 million prize for the winner. Final deadline for entry is 5 October 2006.



    Japan and Korea are in a neck-and-neck competition to produce the world's most human-looking android. Below is Korea's latest entry, developed by the Korean Institute for Industrial Technology and unveiled last month. Unlike Japan's Actroid, introduced in 2003, EveR-1, as “she” is known, can look you in the eye because a camera that recognizes movement is located in the head. She can hold short conversations in Korean and English with her 400-word vocabulary, moving her lips correspondingly. She has 15 facial expressions and will show displeasure if you poke her. Her lower half has yet to be worked out, but scientists say EveR-1 can serve educational functions such as museum guide and reading to children.