The power of thought just got a lot more powerful. Scientists have created a cranial implant that allows monkeys to control a robotic arm just by thinking about it. Using brain signals, the monkeys persuaded the arm to pick up and feed them chunks of zucchini, cucumbers and apples.

Last winter, neuroscientist Andrew Schwartz and his team at the University of Pittsburgh trained monkeys to think about reaching for food (the animals' arms had been temporarily restrained). Using almost 200 electrodes