New Scientist: Evan Peck of Tufts University in Medford, Massachusetts, and his colleagues have developed a device that lets them monitor whether a person is concentrating or otherwise mentally engaged. They used a technique called functional near-IR spectroscopy to shoot IR light from an emitter attached to the wearer’s forehead into the brain’s prefrontal cortex. Some of the light is absorbed by both oxygenated and deoxygenated hemoglobin, and the rest is reflected. By measuring the changes in the amount of light reflected, the headset can detect when the wearer is concentrating. Matching the periods of activity with knowledge of what the person was looking at allowed Peck’s team to determine what information the wearer considered “useful.” When the researchers used the device to test a movie rating system, they found that more favorable ratings were associated with more activity in the prefrontal cortex. They were then able to use that information to generate, and further modify, movie recommendations. Similar systems are being tested for managing work loads for flight controllers and for testing heads-up displays for driving vehicles. Peck’s group plans to develop a version of the device that allows for more advanced interactions.