Relations between aging sensory/sensorimotor and cognitive functions.

Recent evidence is reviewed to examine relations among sensory, sensorimotor, and cognitive aging. Age-heterogeneous cross-sectional data sets show substantial covariation among sensory, sensorimotor and intellectual abilities, and an increase in covariation from adulthood to old and very old age. Recent longitudinal analyses suggest that changes in sensory and intellectual functioning are interrelated. Experimental studies investigate the interdependence between cognitive and sensory/sensorimotor aging by examining the effects of simulated sensory loss on cognitive performance, or the effects of cognitive load manipulations on sensory or motor performance. Generally, both types of manipulations hinder older adults' performance more than that of younger adults. Theoretically, the age-associated intensification of the links among sensory, sensorimotor and cognitive functions observed both correlationally and experimentally may point to (a). common causes influencing all three functions; (b). an increase in resource overlap, cross-domain resource competition, and compensatory tradeoffs; and (c). a combination of the two. Future research aiming at discerning the relative import of these possibilities would profit from an integration of experimental and correlational research strategies.