The Effect of Healthy Aging on the Perception- Action Dissociation

Abstract

The two visual pathways hypothesis posits distinct brain systems for vision-for-perception and vision-for-action. While this dissociation is well-established in younger adults, its integrity in healthy aging remains unclear. To address this, younger (n = 25, range: 18–25 years) and older adults (n = 25, range: 60–95 years) completed estimation and grasping tasks in two experiments. In Experiment 1, two rectangular objects with varying lengths (40 mm and 42 mm) were placed on the “far” and “close” surfaces of a Ponzo illusion board. Despite age-related changes in grasping kinematics, the perception–action dissociation persisted: the illusion influenced estimation, while grasping showed a reversed effect. Experiment 2 tested whether this reversal was due to surface size by removing illusory cues and varying only the background surface size (“big” versus “small”). While estimation was unaffected, surface size modulated grasping in both groups, with a stronger effect in older adults. These findings indicate that the perception–action dissociation is preserved in aging, but older adults rely more on contextual cues during action, potentially reflecting compensatory mechanisms to maintain visuomotor performance in daily life.