Are you out of touch with reality? Baby can tell

Very young children -- even infants -- can realize that other people see the world differently than they do, a new study suggests. And, they seem to make this realization automatically, without deliberate effort, the authors report in journal Science.

The ability to infer others’ intentions and beliefs, often known as “theory of mind,” is an essential part of social interactions and may have been a central condition for the evolution of cooperative human societies. Until a few years ago, it was generally accepted that theory of mind abilities didn’t arise until children were three or four years old. Since then, a flurry of studies using a variety of methods has suggested that much younger humans might in fact possess this capacity.

Ágnes Melinda Kovács and colleagues have devised a new approach to this question and applied it to both adults and to seven-month-old infants. The experiments involved showing the test subject a series of animated videos in which a ball first rolls behind a small wall, and then either stays there, rolls out of view, or rolls away and comes back.

A cartoon character observes different intervals of this process. At the end of each video, the researchers measured how long it took the test subjects to detect the ball. (For the babies, the researchers inferred this based on how long it took the infants to look away from the screen.)

Both the adults’ and infants’ reaction times were faster when the cartoon character’s “belief” about the ball’s location matched the ball’s actual whereabouts. This was the case even when the cartoon character had left the screen by the end of the video. Kovács and colleagues conclude that from seven months on we automatically perceive other people’s points of view, and even when these other people are no longer present, we still remember their beliefs as alternative representations of the world.