Age-related differences in the weighting of kinematic and contextual information during action prediction.

Introduction: Predicting others' behaviors is an essential ability to interact efficiently within the social world. Previous evidence suggests that action prediction entails the integration of incoming sensory information with previous experience and contextual expectations. While it is well known that motor and cognitive functions face age-related changes, research examining how action prediction abilities evolve across the lifespan remains limited. Methods: Here, we compared the action prediction performance of 30 young and 30 older adults in a temporal occlusion paradigm displaying everyday actions embedded in breakfast scenarios. We asked participants to predict the outcome (i.e., to eat or to move) of reaching-to-grasp movements towards big or small food objects (i.e., krapfen or cream puff). Actions were embedded in contexts cueing to an eating or a moving intention, either congruently or incongruently with kinematics. We also measured participants' imaginary abilities and level of identification of actions. Results: Compared to young adults, older adults showed lower sensitivity at predicting actions when they were interrupted early, but not later. At the same time, they were less affected by response bias, particularly for late-interrupted actions. Beside reduced sensitivity, older adults' response speed in predicting early-interrupted actions benefitted more than that of young adults from contextual information. Notably, contextual modulation was stronger in individuals with more intense kinesthetic sensations during motor imagery, particularly within the young group. Discussion: The results suggest that, while action prediction skills seem to reduce with aging, older adults tend to rely more heavily on contextual cues when predicting others' behavior, which may serve as a compensatory mechanism under certain conditions.