Using a head-mounted camera to infer attention direction

A head-mounted camera was used to measure head direction. The camera was mounted to the forehead of 20 6and 20 12-month-old infants while they watched an object held at 11 horizontal ( 80 to þ 80 ) and 9 vertical ( 48 to þ 50 ) positions. The results showed that the head always moved less than required to be on target. Below 30 in the horizontal dimension, the head undershoot of object direction was less than 5 . At 80 , however, the undershoot was substantial or between 10 and 15 . In the vertical dimension, the undershoot was larger than in the horizontal dimension. At 30 , the undershoot was around 25% in the downward direction and around 40% in the upward direction. The size of the undershoot was quite consistent between conditions. It was concluded that the head-mounted camera is a useful indicator of horizontal looking direction in a free looking situation where the head is only turned moderately from a straight ahead position.