Terje Falck-Ytter and his colleagues at Uppsala University in Sweden tested the responses of 11 babies, 11 toddlers and 11 adults when watching nine identical videos of an actor's hand placing three toys into a bucket. Both adults and toddlers moved their eyes to the bucket before the hand finished its motion and did so in roughly the same amount of time. The babies, however, did not shift their eyes until the hand had reached the bucket.
Similar trials with mechanical motion or toys moving without a hand did not result in either adults, infants or babies looking ahead, leading the team to speculate that the mirror neuron system might be responsible for the ability. This system, first discovered in macaque monkeys, allows primates to map the actions of others in the same areas of the brain that would be activated if they undertook the action themselves.
This theory is further reinforced by the fact that six-month-old babies cannot predict the action. Human infants usually learn to place toys in buckets at some point in the latter half of the first year of life. If the mirror neuron system is indeed involved then only one-year-olds should be able to predict such actions. The research was published online in Nature Neuroscience yesterday.