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 6- and 20 12-month-old infants while they watched an object held at 11 horizontal (-80 degrees to + 80 degrees) and 9 vertical (-48 degrees to + 50 degrees) positions. The results showed that the head always moved less than required to be on target. Below 30 degrees in the horizontal dimension, the head undershoot of object direction was less than 5 degrees. At 80 degrees, however, the undershoot was substantial or between 10 degrees and 15 degrees. In the vertical dimension, the undershoot was larger than in the horizontal dimension. At 30 degrees, 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.