Does Unimanual Hand Preference Predict Rdbm Hand Preference During Infancy?

Publication Date


Document Type





Julie Campbell

Mentor Department



Research demonstrates that unimanual manipulation appears before the onset of role-differentiated bimanual manipulations (RDBM; Nelson, Campbell, & Michel, 2013). RDBM appears around 9 months (Babik & Michel, 2016a). Hand preference in one manual skill concatenates into the next manual skill developed (Hinojosa, Sheu, & Michel, 2003). Nelson et al. (2013) found that infant hand preference for acquiring objects is related to hand preference for RDBM during toddlerhood. In the current study, we examine the development of hand preference of unimanual manipulation and the development of RDBMs during infancy by observing the hand preference of both behaviors across 9- to 14-month age period. Thirty infants were observed during a play situation in which a researcher presented objects to an infant while seated at a table. During the unimanual manipulation portion, 17 pairs of identical objects were placed in the infant's hands in monthly sessions. During the RDBM manipulations task, 32 objects were placed on the table within reaching distance of the infant. RDBM actions were coded when infants used one hand to stabilize an object and the other hand to manipulate them. The hand that has an active manipulating role on an object was coded as the preferred hand. No RDBM action was coded if infants did not engage in playing with an object or used only one hand to manipulate an object. Video recordings were analyzed for the number of unimanual and RDBMs that the infant performed during each monthly session. Ten infants with a left-hand preference, right-hand preference, no hand preference for unimanual manipulations were examined. Hierarchical linear modeling was used to create trajectories of each of the behaviors across the 9 to 14-month period and to analyze the relation between the intercepts and slopes of these trajectories. The results show that there is a relation between unimanual manipulations and RDBMs such that, across 9 to 14 months, the no hand preference and right hand preference groups for unimanual show an increase in right RDBM performance, whereas the left hand preference group shows a decrease in right RDBM performance. Babik, Michel, Sheu, and Campbell (2014) showed that infants decreased the amount of right hand acquisitions around 9-10 months. Our study supports the theory that skill for acquisition concatenates into RDBM skills because infants with a right hand preference for unimanual increase in their preference for RDBM.


Pattanakul-graduate, Flores-undergraduate, Mordan-undergraduate

This document is currently not available here.