This book elaborates a series of contributions to a non–representational theory of action and perception. It is based on current theoretical developments in the enactive approach to life and mind. These enactive ideas are applied and extended to provide a theoretically rich, naturalistic account of sensorimotor meaning and agency. This account supplies non–representational extensions to the sensorimotor approach to perceptual experience based on the notion of the living body as a self–organizing dynamic system in coupling with the environment. The enactive perspective entails the use of world–involving explanations, in which processes external to an agent co–constitute mental phenomena in ways that cannot be reduced to the supply of information for internal processing. These contributions to sensorimotor theories are a dynamical–systems description of different types of sensorimotor regularities or sensorimotor contingencies, a dynamical interpretation of Piaget's theory of equilibration to ground the concept of sensorimotor mastery, and a theory of agency as organized networks of sensorimotor schemes, with its implications for sensorimotor subjectivity. New tools are provided for examining the organization, development, and operation of networks of sensorimotor schemes that compose regional activities and genres of action with their own situated norms. This permits the exploration of new explanations for the phenomenology of agency experience that are favorably contrasted with traditional computational approaches and lead to new empirical predictions. From these proposals, capabilities once beyond the reach of enactive explanations, such as the possibility of virtual actions and the adoption of socially mediated abstract perceptual attitudes, can be addressed.

According to the sensorimotor approach, perception is a form of embodied know-how, constituted by lawful regularities in the sensorimotor flow or in sensorimotor contingencies (SMCs) in an active and situated agent. Despite the attention that this approach has attracted, there have been few attempts to define its core concepts formally. In this paper, we examine the idea of SMCs and argue that its use involves notions that need to be distinguished. We introduce four distinct kinds of SMCs, which we define operationally. These are the notions of sensorimotor environment (open-loop motor-induced sensory variations), sensorimotor habitat (closed-loop sensorimotor trajectories), sensorimotor coordination (reliable sensorimotor patterns playing a functional role), and sensorimotor strategy (normative organization of sensorimotor coordinations). We make use of a minimal dynamical model of visually guided categorization to test the explanatory value of the different kinds of SMCs. Finally, we discuss the impact of our definitions on the conceptual development and empirical as well as model-based testing of the claims of the sensorimotor approach.

The sensorimotor approach to perception addresses various aspects of perceptual experience, but not the subjectivity of intentional action. Conversely, the problem that current accounts of the sense of agency deal with is primarily one of subjectivity. But the proposed models, based on internal signal comparisons, arguably fail to make the transition from subpersonal computations to personal experience. In this paper we suggest an alternative direction towards explaining the sense of agency by braiding three theoretical strands: a world-involving, dynamical interpretation of the sensorimotor approach, an enactive description of sensorimotor agency as contrasted with organic agency in general, and a dynamical theory of equilibration within and between sensorimotor schemes. On this new account, the sense of oneself as the author of one's own actions corresponds to what we experience during the ongoing adventure of establishing, losing, and re-establishing meaningful interactions with the world. The meaningful relation between agent and world is given by the precarious constitution of sensorimotor agency as a self-asserting network of schemes and dispositions. Acts are owned as they adaptively assert the constitution of the agent. Thus, awareness for different aspects of agency experience, such as the initiation of action, the effort exerted in controlling it, or the achievement of the desired effect, can be accounted for by processes involved in maintaining the sensorimotor organization that enables these interactions with the world. We discuss these processes in detail from a non-representational, dynamical perspective and show how they cohere with the personal experience of agency.

Distance estimation of visually simulated self-motion is difficult, because one has to know or make assumptions about scene layout to judge ego speed. Discrimination of the travel distances of two sequentially simulated self-motions in the same scene can be performed quite accurately (Bremmer and Lappe 1999; Frenz et al., 2003). However, the indication of the perceived distance of a single movement in terms of a spatial interval results in a depth scaling error: Intervals are correlated with the true travel distance, but underestimate travel distance by about 25% (Frenz and Lappe, 2005). Here we investigated whether the inclusion of further depth cues (disparity/motion parallax/figural cues) in the virtual environment allows more veridical interval adjustment. Experiments were conducted on a large single projection screen and in a fully immersive computer-animated virtual environment (CAVE). Forward movements in simple virtual environments were simulated with distances between 1.5 and 13 m with varying speeds. Subjects indicated the perceived distance of each movement in terms of a depth interval on the virtual ground plane. We found good correlation between simulated and indicated distances, indicative of an internal representation of the perceived distance. The slopes of the fitted regression lines revealed an underestimation of distance by about 25% under all conditions. We conclude that estimation of travel distance from optic flow is subject to scaling when compared to static intervals in the environment, irrespective of additional depth cues

Learning to perceive is faced with a classical paradox: if understanding is required for perception, how can we learn to perceive something new, something we do not yet understand? According to the sensorimotor approach, perception involves mastery of regular sensorimotor co-variations that depend on the agent and the environment, also known as the “laws” of sensorimotor contingencies (SMCs). In this sense, perception involves enacting relevant sensorimotor skills in each situation. It is important for this proposal that such skills can be learned and refined with experience and yet up to this date, the sensorimotor approach has had no explicit theory of perceptual learning. The situation is made more complex if we acknowledge the open-ended nature of human learning. In this paper we propose Piaget’s theory of equilibration as a potential candidate to fulfill this role. This theory highlights the importance of intrinsic sensorimotor norms, in terms of the closure of sensorimotor schemes. It also explains how the equilibration of a sensorimotor organization faced with novelty or breakdowns proceeds by re-shaping pre-existing structures in coupling with dynamical regularities of the world. This way learning to perceive is guided by the equilibration of emerging forms of skillful coping with the world. We demonstrate the compatibility between Piaget’s theory and the sensorimotor approach by providing a dynamical formalization of equilibration to give an explicit micro-genetic account of sensorimotor learning and, by extension, of how we learn to perceive. This allows us to draw important lessons in the form of general principles for open-ended sensorimotor learning, including the need for an intrinsic normative evaluation by the agent itself. We also explore implications of our micro-genetic account at the personal level.