Faculty Mentor Information
Dr. Iryna Babik (Mentor), Boise State University
Abstract
Manual lateralization, or hand preference, emerges in infancy and gets manifested in object acquisition and manipulation. The magnitude of manual lateralization refers to the strength of hand preference, irrespective of its direction (right vs. left). Manual lateralization has evolved as a useful adaptation, but does it improve manual performance? Previous research showed inconsistent results on the relation between manual lateralization and manual performance. This may have been due to differences in measures of hand preference, with some research looking at the direction rather than magnitude of manual lateralization. The aim of this research was to determine whether the magnitude of infants’ manual lateralization was related to the performance of role-differentiated bimanual manipulation (RDBM) and tool-use (TU). This longitudinal study included 158 full-term infants (91 males, aged 9.13 ± 0.15 months at baseline) who were tested monthly from 9 to 14 months. Statistical analyses were performed using HLM software. Results revealed that the magnitude of manual lateralization was negatively associated with RDBM performance, suggesting that infants with a weaker hand preference performed more RDBMs than those with a stronger hand preference. It was also shown that the magnitude of infants’ manual lateralization had no association with TU performance. Therefore, a coupling of the hands (using both hands collaboratively during a task, or frequently switching from left to right) showed to be the best predictor of advanced RDBM performance. This research emphasizes the importance of bimanual use in infants since it may facilitate the development of complex coordination during bimanual tasks.
Is Manual Lateralization Associated with Manual Performance?
Manual lateralization, or hand preference, emerges in infancy and gets manifested in object acquisition and manipulation. The magnitude of manual lateralization refers to the strength of hand preference, irrespective of its direction (right vs. left). Manual lateralization has evolved as a useful adaptation, but does it improve manual performance? Previous research showed inconsistent results on the relation between manual lateralization and manual performance. This may have been due to differences in measures of hand preference, with some research looking at the direction rather than magnitude of manual lateralization. The aim of this research was to determine whether the magnitude of infants’ manual lateralization was related to the performance of role-differentiated bimanual manipulation (RDBM) and tool-use (TU). This longitudinal study included 158 full-term infants (91 males, aged 9.13 ± 0.15 months at baseline) who were tested monthly from 9 to 14 months. Statistical analyses were performed using HLM software. Results revealed that the magnitude of manual lateralization was negatively associated with RDBM performance, suggesting that infants with a weaker hand preference performed more RDBMs than those with a stronger hand preference. It was also shown that the magnitude of infants’ manual lateralization had no association with TU performance. Therefore, a coupling of the hands (using both hands collaboratively during a task, or frequently switching from left to right) showed to be the best predictor of advanced RDBM performance. This research emphasizes the importance of bimanual use in infants since it may facilitate the development of complex coordination during bimanual tasks.