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 data sets from eye-trackers requires users to think hard about what they are measuring and what these measures mean for making inferences about underlying cognitive processes. The present LDE225 mw commentary highlights these concerns, both technical and interpretive, and reviews the five articles that comprise this Special Issue. “
“Developmental changes in learning from peers and adults during the second year of life were assessed using an imitation paradigm. Independent groups of 15- and 24-month-old infants watched a prerecorded

video of an unfamiliar child or adult model demonstrating a series of actions with objects. When learning was assessed immediately, 15-month-old infants imitated the target actions from the adult, but not the peer whereas 24-month-old infants imitated PS341 the target actions from both models. When infants’ retention was assessed after a 10-min delay, only 24-month-old infants who had observed the peer model exhibited imitation. Across both ages, there was a significant positive correlation between the number of actions imitated from the peer and the length of regular peer exposure reported by caregivers. Length of peer exposure was not related to imitation from the adult model. Taken together, these findings indicate that a peer-model advantage develops as a function of age and experience during the second year of life. “
“Infants typically exhibit a shift from unimanual to bimanual reaching toward

the end of their first year, which has been linked to walking onset. Until now, however, it has been unclear whether it was the onset of walking per se that influenced reaching PRKD3 patterns or whether a more general shift to an upright posture might have prompted the reorganization of the motor system. To address this question, the current study longitudinally chronicled the uni- and bimanual reaching preferences of 25 infants every 3 weeks starting at 7 months, prior to the onset of pulling-to-stand and through the onset of cruising. Experimenters recorded infants’ reaching behavior via a semi-structured reaching procedure and documented their motor development. There was no relationship between the shift from uni- to bimanual reaching and the onset of pulling-to-stand. However, the onset of cruising was related to a shift in reaching pattern preference, suggesting that the increase in infants’ bimanual reaching was prompted by a reorganization of the motor system in which the arms are recruited for use in new ways to support locomotion. We also discuss individual differences in the trajectory of reaching activity in terms of the pitfalls of using age as an explanatory variable.