A simple system for monitoring the timing of infant gaze to stimuli at specific locations

A system for monitoring the timing of infant gazes to specific locations is described. Infants sit on a parent’s lap in a dark room and observe videotaped stimuli presented on one of four monitors. Infrared (IR) light sources provide illumination for an IR-sensitive video camera and are positioned so that the infant’s direction of gaze can be readily apprehended on the basis of the reflections of the IR light sources relative to the infant’s pupil. The parent monitors the infant’s eyes through a headmounted display and keeps the infant in view of the video camera. Direction and timing of gaze shifts can be coded from frame-by-frame inspection of the videotape. We demonstrate that this coding is relatively accurate and that the present system provides some advantages over coding gaze direction on the basis of an unembellished video recording.