Using writing instruments: invariances in young children and adults.

In 2 studies, developmental changes in variability associated with handwriting were investigated. In Study 1, variability in grip patterns and pen positioning relative to a flat surface were examined in 3- and 5-year-olds and adults. The results indicated that between 3 and 5 years of age there is a reduction in the number of grips that individual children routinely use and a reduction in variability associated with pen-surface positioning. In Study 2, the 3-year-old children who participated in Study 1 were tested 6 months later. In comparison to young 3-year-old children, older 3-year-olds use an adult grip pattern more often and are less variable in pen-surface positioning, although the use of multiple grip patterns is still common. The findings from both studies are considered in relation to prior research that emphasized modal patterns of motor development and newer work that uses developmental changes in variability to understand the acquisition of motor skill.