Why measure handedness
There are many reasons to study the development of hand preference in infants. For one thing, being left-handed can be an advantage in one-on-one sports such as tennis. For example, Rafael Nadal is a left-handed player and with this natural advantage, he is now a star tennis player with many successful matches to his name. The advantage being, in a population with a left-handed minority and a right-handed majority, the left-handed Rafael Nadal plays most of his matches against right-handed opponents and is therefore well-practiced at dealing with this asymmetry. A right-hander plays the majority of his matches against other right-handers. In conclusion, when confronted with left-handers, they are less practiced, thereby giving the lefty a natural advantage.
Measuring handedness in infancy
Recently, Nelson et al. presented “Unimanual to bimanual: Tracking the development of handedness from 6 to 24 months”. One of their findings was that, as infants, 39% of these children showed preference for the right hand, whereas 61% had no hand preference. In toddlerhood, this 39% increased to 97%. This study provides some evidence that handedness might begin to stabilize earlier than traditionally assumed. However, in order to confirm this conclusion, more research was required.
Nelson et al. were particularly interested in asymmetric bimanual actions. Nelson et al. explain: The current study is the first longitudinal attempt to connect unimanual and bimanual preferences, and emerging handedness patterns, over repeated monthly assessments in a large group of developing children (N = 38). They focused on actions where two hands work together to achieve a goal, a skill known as Role-Differentiated Bimanual Manipulation (RDBM).