An active inference model of hierarchical action understanding, learning and imitation

We advance a novel active inference model of the cognitive processing that underlies the acquisition of a hierarchical action repertoire and its use for observation, understanding and imitation. We illustrate the model in four simulations of a tennis learner who observes a teacher performing tennis shots, forms hierarchical representations of the observed actions, and imitates them. Our simulations show that the agent's oculomotor activity implements an active information sampling strategy that permits inferring the kinematic aspects of the observed movement, which lie at the lowest level of the action hierarchy. In turn, this low-level kinematic inference supports higher-level inferences about deeper aspects of the observed actions: proximal goals and intentions. Finally, the inferred action representations can steer imitative responses, but interfere with the execution of different actions. Our simulations show that hierarchical active inference provides a unified account of action observation, understanding, learning and imitation and helps explain the neurobiological underpinnings of visuomotor cognition, including the multiple routes for action understanding in the dorsal and ventral streams and mirror mechanisms

The cognitive and neural representations of actions

The aim of this thesis is to explore how people assign meaning to actions. For that reason, I investigated the cognitive and neural structures underlying action representations, taking into account the key features of actions and the categories that these actions form. The thesis consists of five chapters. The first chapter provides a general background on the topic of action understanding and the methods I chose for analyzing the data. Chapters 2 - 4 incorporate the three main studies that I conducted throughout the PhD project. Chapter 5 includes a general discussion, the implications of the studies, their limitations, and ideas for future studies. The article presented in Chapter 2 has been published in Behavior Research Methods (impact factor = 5.95) on July 5th 2022. The manuscript in Chapter 3 has been submitted to Human Brain Mapping (impact factor = 5.40) and is currently in revision. All references have been combined into one bibliography at the end of the thesis. Supplementary files and figures for all three manuscripts have been merged in the Appendix following Chapter 5. No further changes have been made to the text of the published article. The PhD project has been funded by a Research Grant from the German Research Foundation (Li 2840/1-1). I was supported by the Research Grant from the German Research Foundation (Li 2840/1-1) and the stipend from Finanzielles Anreizsystem zur Förderung der Gleichstellung