The Perceptual Basis Of Spatial Representation

First Proofs Friday, July 17 2009 1 2 1 The perceptual basis of spatial representation Vyvyan Evans 3 Overview 4 24 The human experience of space includes knowledge relating to the size, shape, location and distribution of entities in a stable three-dimensional environment. In this introductory chapter I address the perceptual systems and processes that facilitate this: the sense-perceptory and brain mechanisms that process perceptual information giving rise to spatial experience. I also examine the processes whereby perceptual experience is redescribed into rudimentary representations of space. That is, I examine primitive concepts which form the bedrock of our ability to think, reason and talk about space and, indeed, more abstract realms. Thus, this chapter is concerned primarily with i) the perception of space, and the way in which spatial experience is ‘constructed’ by virtue of our sense-perceptory systems and brain mechanisms, and ii) how spatial experience is ‘redescribed’, giving rise to foundational spatial concepts prior to the emergence of language from around one year onwards. The chapter begins by examining the distinction between spatial representations, exploring the difference between percepts and concepts. I then examine the human perceptual systems which facilitate the detection of sensory stimuli from the external environment. I then look at perceptual theories which attempt to explain how the brain constructs spatial experience from this sensory input. I then turn to the human mapping ability: an innate mechanism that allows us to construct spatial or cognitive ‘maps’ based on locational information. This ability is essential for wayfaring, which is to say navigating in space. I then examine how percepts are redescribed as the basic spatial primitives, known as image schemas. 25 1 Introduction: perception vs conception 26 My main concern in this chapter is to review the way in which space is experienced and constructed by the human sensory (or sense-perceptory) systems, and the brain. I also review the way in which these objects of spatial perception known as percepts give rise to rudimentary spatial representations (or concepts) known as image schemas. Accordingly, at this point I briefly review the distinction between perception (and percepts), and conception (and concepts). Perception consists of three stages: i) sensation ii) perceptual organisation and iii) identification and recognition. Sensation concerns the way in which external energy, such as light, heat, or (sound) vibrations are converted into the neural codes which the brain recognises. Perceptual organisation concerns the way in which this sensory informa- 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 27 28 29 30 31 32 33 34 35 21 First Proofs Friday, July 17 2009 language, cognition and space 22 7 tion is organised and formed into a perceptual object, a percept. Identification and recognition relates to the stage in the process whereby past experiences and conceptual knowledge is brought to bear in order to interpret the percept. For instance, a spherical object might be identified and recognised as a football or a coin, or a wheel, or some other object