The manifestation of infant hand-use preferences when reaching for objects during the seven--to thirteen-month age period.

Handedness is an aspect of hemispheric specialization whose pattern of expression may signal an unusual specialization that in turn, may underlie several developmental psychopathologies. It is generally believed that infant handedness is neither stable nor reliable and hence, cannot be used as an early marker of potential developmental abnormality of hemispheric specialization. We show that infant hand-use preferences for apprehending objects can be reliably assessed and may be relatively stable throughout the 7-13 month age period. However, the results also demonstrate that identifying infant handedness requires assessment using very large sample sizes with multiple assessment periods because it is likely that there may be many more than three patterns in the development of handedness during infancy.