As a time-honored way to make decisions in Japan, adults often resort to janken, a local version of the child's game of rock, paper, scissors. Japanese scientists have developed a new twist on this tradition, a machine that can read minds and then form the "weapon" of choice on a mechanical hand--in effect, a mind-controlled robot.

The joint project by Kyoto-based Advanced Telecommunications Research (ATR) Institute International and Honda Research Institute Japan is a novel "brain-machine interface." In the ATR-Honda approach, demonstrated this past May, a subject in a functional magnetic resonance imaging (fMRI) machine forms the rock, paper or scissors with his hand. A machine-learning algorithm analyzes the fMRI data on changes in blood flow connected with neural activity in the motor cortex. The decoded data are transmitted to the robot hand, which reproduces the choice within about seven seconds and with 85 percent accuracy.