Eye-trackers suitable for use with infants are now marketed by several commercial vendors. As eye-trackers become more prevalent in infancy research, there is the potential for users to be unaware of dangers lurking "under the hood" if they assume the eye-tracker introduces no errors in measuring infants' gaze. Moreover, the influx of voluminous…

In 2004, McMurray and Aslin edited for "Infancy" a special section on eye tracking. The articles in that special issue revealed the enormous promise of automatic eye tracking with young infants and demonstrated that eye-tracking procedures can provide significant insight into the emergence of cognitive, social, and emotional processing in infancy.…

Yoshida and Smith (this issue) provide one of the first attempts to overcome the most serious impediment to the use of head-mounted eye trackers with infants: Except in rare cases they are not light enough to be worn on an infant's head, or the infant does not tolerate looking through a half-silvered mirror that is hanging on a rigid stalk…