Perception, Action and Neuroscience

The main aim of this thesis is to offer new insights in our understanding of the relationships between visual perception and action. Starting from experimental results in vision and motor neuroscience, it will do this by suggesting new functional characteristics – which are neglected in the literature – of vision-for-action and of motor perception. The crucial task of these characteristics is to compute, from a motor point of view, the most suitable way we can interact with the external environment. A better understanding of these characteristics requires an investigation into the nature of the computational mechanisms through which our visuomotor brain can lead us to perceive the possibilities of action in this external environment. Describing in a coherent way the nature of the relation between the visual processes that allow us to guide action and the motor processes at the basis of our motor skills is one of the most yarned enterprises in both contemporary philosophy and neuroscience, insofar as opening the “black-box” of the mental representations by which vision-for-action is subserved – in the literature they are called motor representations (MRs) – means to understand in general how the way embodied agents can actively couple with the external environment. Here, I want to offer a specific contribution to several open, central issues, each concerning the relation between visual perception and action, and each familiar from the literature concerning the philosophy of neuroscience. Starting from two specific empirical frameworks, the one of the ‘Two Visual Systems Model’ and the other of a model of ‘Motor Perception', the project will shed new light on the mental processes that allow us to visually perceive action possibilities in the external environment. Indeed, it is known that these processes convert the visual information about the objects we are faced with into motor information that we can use to interact with those objects. But what kind of mental representations do these processes rely on? This is the foundational question guiding my overall research. Answering this general question requires a discussion of several more specific issues connected with it. I will confront these issues, and thus answer my main question, by starting from the philosophical analysis of the processing of the cortical anatomo-functional correlates, as well as the computational mechanisms these mental phenomena – that is, MRs – rely on. Here is a brief overview of the chapters of this thesis, and the related issues I focus on. Chapter 1 introduces the topic. Chapter 2 reviews and synthesises the massive sets of neuroscientific evidence in a coherent philosophical theory of MRs, something we lack at the moment. The goal of chapter 3 is to show that emotions play a crucial role in forming our mental antecedents of action, insofar as they assist vision-for-action from its early stage processing. Chapter 4 aims to defend the idea, completely new, that the representation of action properties, which is a function of MRs, is possible not only for normal objects, but also for depicted objects. Chapter 5 suggests that depicted objects cannot foster the visual feeling of presence because it is strictly linked to the perception of absolute depth cues that give rise to qualitatively rich stereopsis, which is linked to the perception of the possibility of reliable motor interaction with the object we face with.