Publication Date


Document Type


Degree Type





Julie Campbell

Mentor Department



Role-differentiated bimanual manipulations (RDBMs)are a complex action in which two hands, each performing a different task, work together to accomplish a mutual goal (Babik & Michel, 2015).RDBMs can be used as an indicator of hemispheric specialization for hand preference, and hand preference has been implicated to have an impact on a host of cognitive abilities (Michel, 2017). Hand preference for acquisition and hand preference for RDBM have previously been shown to be related, as infants prefer to use their ipsilateral hand for performing both of these actions (Babik & Michel, 2015). The goal was to examine the relation of hand preference to RDBM efficiency, which is defined as the speed of an infant successfully completing a RDBM action. Thirty (10 right-handed for acquisition, 10 left, and 10 no preference) infants' (20 males) videos were derived from archived data from a larger longitudinal study. Videos were examined for the time taken to successfully complete simple and difficult RDBM actions. The start time was indicated by the infant's initial contact with an object and stop time was indicated by successful completion of a RDBM action. A two-way ANOVA revealed a difference in performance time between the 9 month RDBM performance times and each of the other months of testing, indicating that RDBM speed increased across time. Infants with a left acquisition hand preference (M= 6.14) performed RDBMs significantly faster than infants with a late right preference (M= 7.64).