Action prediction ability: from healthy aging to Parkinson pathophysiology

This thesis integrates theoretical discussion and empirical contributions to provide a systematic examination of Action Prediction, progressing from foundational conceptual framework to applied research in healthy aging and people with PD. Chapter 1 outlines the core cognitive and neural mechanisms of action perception and prediction, including prediction error (PE) processes and their relevance for everyday social interactions. Chapter 2 synthesized evidence on age-related changes in predictive processing, thereby establishing the conceptual and empirical background for the first experimental study presented in Chapter 3, which examines age-related modulation of AP using the proposed behavioral framework. Chapter 4 introduces a complementary methodological contribution by presenting the validation and psychometric evaluation of the Italian version of the Behavioral Identification Form. By providing a reliable measure of individual differences in hierarchical action representation, this chapter supplies a critical tool for interpreting variability in predictive performance across both healthy aging and clinical populations. The second part of the thesis focuses on PD. Chapter 5 reviews evidence on predictive processing alterations associated with Parkinson’s disease, with a focus on how the condition impacts action perception and prediction. Chapter 6 then presents an empirical investigation of AP in individuals with PD compared with age-matched healthy adults, applying the same behavioral framework used to examine age-related changes. By integrating these findings with an explicit focus on individual differences, the thesis moves beyond descriptive accounts of performance decline and provides a framework for disentangling predictive sensitivity, decisional strategies, and representational factors across healthy aging and PD.