Background/Purpose The ability to mentally represent action in space is important to movement planning and execution. An important outcome of action representation is the prediction and consequences of intended actions. Research indicates quite clearly that motor imagery provides a window into this process. Using a lifespan design, we examined children, young adults, and elderly persons on their ability to estimate reachability via use of motor imagery.
Method Children (M = 8 years), young adults (M = 20 years), and a group of elderly persons (M = 77 years) were instructed to estimate via use of motor imagery whether randomly presented targets in peripersonal (within actual reach) and extrapersonal (beyond reach) space were within or out of reach of their dominant limb while seated. Imagined responses were compared to the individual's scaled maximum reach. Each participant received 35 trials randomly presented across seven target distances with five trials per site.
Analysis/Results ANOVA results for accuracy indicated that children and the elderly were similar, with scores significantly lower than those of young adults (p < .01). Whereas all groups displayed greater error in extrapersonal space, once again children and the elderly were similar, but significantly different than young adults. That is, children and elderly displayed greater overestimation responses.
Conclusions Although other factors are discussed, we speculate that differences are due to distinctions in brain structure and functioning – namely, immature development (in children) and decline in the elderly in the parietal cortex and other areas associated with mental representation.