Asymmetrical hand usage in infancy: An ethological approach

Observations of the motor behavior of 22 infants were made by 8-hour daily video recording of nursery school activity over 11 days. Recorded object-oriented manipulating or holding actions were scored as the number of movements made by each hand separately and together, by each child, each day, and the average duration of hand activity. For the group, the right hand made significantly more movements than the left, and the duration of right-hand use was longer than the left. Although individual differences in frequency of hand use were reliably consistent, they were not for movement duration. The results show that data from spontaneous object manipulation can be a highly reliable and valid means of assessing differences in hand usage.