The ontogeny of visual-motor memory and its importance in handwriting and reading: a developing construct.

Humans have evolved a remarkable ability to remember visual shapes and use these representations to generate motor activity (from Palaeolithic cave drawings through Jiahu symbols to cursive handwriting). The term visual-motor memory (VMM) describes this psychological ability, which must have conveyed an evolutionary advantage and remains critically important to humans (e.g. when learning to write). Surprisingly, little empirical investigation of this unique human ability exists--almost certainly because of the technological difficulties involved in measuring VMM. We deployed a novel technique for measuring this construct in 87 children (6-11 years old, 44 females). Children drew novel shapes presented briefly on a tablet laptop screen, drawing their responses from memory on the screen using a digitizer stylus. Sophisticated algorithms (using point-registration techniques) objectively quantified the accuracy of the children's reproductions. VMM improved with age and performance decreased with shape complexity, indicating that the measure captured meaningful developmental changes. The relationship between VMM and scores on nationally standardized writing assessments were explored with the results showing a clear relationship between these measures, even after controlling for age. Moreover, a relationship between VMM and the nationally standardized reading test was mediated via writing ability, suggesting VMM's wider importance within language development.