This is a book about how we see: the environment around us (its surfaces, their layout, and their colors and textures); where we are in the environment; whether or not we are moving and, if we are, where we are going; what things are good for; how to do things (to thread a needle or drive an automobile); or why things look as they do.The basic assumption is that vision depends on the eye which is connected to the brain. The (...) author suggests that natural vision depends on the eyes in the head on a body supported by the ground, the brain being only the central organ of a complete visual system. When no constraints are put on the visual system, people look around, walk up to something interesting and move around it so as to see it from all sides, and go from one vista to another. That is natural vision—and what this book is about. (shrink)

This paper concerns how motor actions are neurally represented and coded. Action planning and motor preparation can be studied using a specific type of representational activity, motor imagery. A close functional equivalence between motor imagery and motor preparation is suggested by the positive effects of imagining movements on motor learning, the similarity between the neural structures involved, and the similar physiological correlates observed in both imaging and preparing. The content of motor representations can be inferred from motor images at a (...) macroscopic level, based on global aspects of the action and the motor rules and constraints which predict the spatial path and kinematics of movements. A more microscopic neural account calls for a representation of object-oriented action. Object attributes are processed in different neural pathways depending on the kind of task the subject is performing. During object-oriented action, a pragmatic representation is activated in which object affordances are transformed into specific motor schemas. Animal as well as human clinical data implicate the posterior parietal and premotor cortical areas in schema instantiation. A mechanism is proposed that is able to encode the desired goal of the action and is applicable to different levels of representational organization. (shrink)

When two or more people coordinate their actions in space and time to produce a joint outcome, they perform a joint action. The perceptual, cognitive, and motor processes that enable individuals to coordinate their actions with others have been receiving increasing attention during the last decade, complementing earlier work on shared intentionality and discourse. This chapter reviews current theoretical concepts and empirical findings in order to provide a structured overview of the state of the art in joint action research. We (...) distinguish between planned and emergent coordination. In planned coordination, agents' behavior is driven by representations that specify the desired outcomes of joint action and the agent's own part in achieving these outcomes. In emergent coordination, coordinated behavior occurs due to perception action couplings that make multiple individuals act in similar ways, independently of joint plans. We review evidence for the two types of coordination and discuss potential synergies between them. (shrink)