Action prediction in the aging mind
MPI series in human cognitive and brain sciences 151
189 pages. Leipzig, Max Planck Institute for Human Cognitive and Brain Sciences (2013)
One of the most essential abilities that enables us to navigate successfully through our social environment and interact with others is the prediction of actions that are performed by other individuals. Based on the widely held assumption of a shared representation between action execution and action observation, the crucial feature for effective prediction is that an observed action is part of the observer’s motor repertoire. This assumption is supported by a vast amount of neuroimaging studies that provide evidence for a remarkable overlap between brain regions recruited during action execution and action observation. At present, however, it is still poorly understood whether and how predictive abilities and their underlying neural mechanisms change over the lifespan due to age-related changes in the brain and body. Therefore, this dissertation investigated how action prediction changes with advancing age and the observers’ level of sensorimotor experience. In two behavioral experiments, evidence was found that there might be a specific age-related decline in the ability to predict observed actions, possibly based on less precise internal action representations. The results further showed that extensive amounts of sensorimotor experience seem to enable experts to predict actions from their domain of expertise more precisely even in older age. In a follow-up fMRI experiment, age-related changes in neural activation patterns during action prediction were examined. The results showed that this task engages a distributed network in the brain that is modulated by the content of the observed actions and the age and experience of the observer. Compared to younger adults, older adults seemed to create a visual image of the observed actions and evaluated its features instead of effectively exploiting their sensorimotor system. Taken together, this dissertation provides new and important insights into the way older adults predict observed actions, as well as the first evidence demonstrating how aging impacts the neural underpinnings of this process.