Infant s Examination and Manipulation of Objects

This study will explore how babies become able to use their experience with objects to plan to manipulate them appropriately. For example, an adult knows that picking up a grocery bag full of canned food requires different actions than are needed for lifting an empty bag. This study will examine when and how infants first begin to adapt their actions to manipulate specific objects that weigh different amounts. Participants will include normal healthy babies within 2 weeks of their first birthday. If the expected results are obtained from testing, 9-month-old children will then be studied to identify a lower age boundary in task performance. If the expected results are not obtained at the 12-month test age, older children will be recruited to participate. The study involves one 30-minute session with the baby and his or her mother or father. The parent will answer some questions about the family, such as its size and ethnic make-up. The infant will then have small magnetic sensors taped to the underside of each arm and to the back. While sitting on the parent s lap, the infant will be presented with plastic toys, and his or her actions will be measured by the sensors as he or she reaches for and picks up the toys. The sensors will be connected to a computer that will track and record the motion of the infant s arms. ...