Abstract
Studies of cognitive, perceptual, and socio-emotional development in infancy have made extensive use of looking time as an outcome measure. These procedures typically rely on assessing infant looking; investigators have primarily focused on mean looking times for groups of infants. This practice, however, obscures information about the individual looks of individual infants. This project addressed this gap by testing the temporal dependency hypothesis: The duration of an infant’s successive looks at a target are positively predicted by the duration of the infant’s previous looks at that target. Temporal dependency was found in the Face-to-Face/Still-Face procedure at 6 months (n = 109); the duration of successive looks at the parent were predicted by the duration of previous looks at the parent. Each individual infant’s level of temporal dependency predicted joint attention on the Early Social Communication Scales (ESCS) at 9 months, but did not predict measures of joint attention on the ESCS at 6 and 12 months, language on the Mullen Scales of Early Learning at 12, 24, or 36 months, or temperament assessed with the Infant Behavior Questionnaire at 12 months. Temporal dependency was also found in an infant-controlled habituation procedure at 6 months (n = 92); the duration of successive looks at a recorded face were predicted by the duration of previous looks at the recorded face. In two contexts, individual infant looks were predictable; past behavior constrained current behavior. Non-random variation due to temporal dependency is an under-appreciated influence on looking behavior in both interactive and non-interactive contexts.