How Vertical Spaces Are Perceived and Represented Daniele Nardi (d.nardi@uniroma1.it) Department of Psychology, Sapienza University of Rome, Via dei Marsi 78 Rome, 00185 Italy Frank H. Durgin (fdurgin1@swarthmore.edu) Department of Psychology, Swarthmore College, 500 College Avenue Swarthmore, PA, 19081 USA Kate J. Jeffery (k.jeffery@ucl.ac.uk) Cognitive, Perceptual and Brain Sciences, University College London, 26 Bedford Way London, WC1H 0AP, UK Steven M. Weisberg (smweis@temple.edu) Department of Psychology, Temple University, 1701 N. 13 th street Philadelphia, PA, 19122 USA Keywords: Vertical spaces; volumes; slope or slant; angular scale expansion; spatial abilities; individual and sex differences; place and grid cells. other angular variables, is exaggerated by the introduction of perceptual biases, such that the range of inclinations relevant to locomotion is more densely coded (Durgin & Li, 2011). This angular scale expansion enables us to more precisely represent small differences in inclinations, and thus may improve the precision of action control. Furthermore, the theory quantitatively predicts the well- reported overestimation of hill slant, suggesting that this phenomenon may not be directly due to a role of effort or physical potential, but to a more general angular coding scheme that is useful for action control as well as route planning and spatial orientation. Beyond perceptual encoding of slope for action, recent research has demonstrated large individual differences in the ability to rely on slope cues for cognitive spatial tasks, including navigation (Weisberg & Newcombe, 2011). Given that slope is a stable and salient part of the lay of the land, a fundamental question explored in a line of research by Weisberg is whether people are able to take slope into account when building a mental map of the environment – and what makes slope difficult to use for some people. Using a navigation task in a virtual environment, it was found that individual’s navigation ability is a crucial factor in determining whether terrain slope facilitated a more accurate representation: in a complex environment, only good navigators were able to take advantage of the information. This result is very important because it can explain previously reported sex-specific difficulties with slope in light of individual differences in broad spatial abilities. Given the theoretical distinctiveness of the vertical component of space, due to its link with the gravity axis, an important question to investigate is the salience of vertical information in spatial learning tasks. Studies on non-human animal models have indicated that vertical information dominates over horizontal information. Recently, a line of research by Nardi has investigated if the same occurs in humans. Reorientation was tested in a real-world Introduction The purpose of this symposium is to highlight how the vertical dimension is perceived and represented differently from the horizontal dimensions, and the role of this dimension in spatial learning. This is a new and important issue because literature on spatial cognition has hitherto neglected the study of the vertical dimension, under the assumption that space can identically be investigated in the horizontal plane. This notion, while untested, ignores a crucial, unique property of the vertical dimension – that of being parallel to the force of gravity, which poses constraints on affordances and energetic potential. Additionally, the ability to move freely in three dimensions imposes computational complexities not present in two. New research impetus is trying to clarify the role of the vertical dimension in space. The present symposium will try to tie together different perspectives (psychophysics, cognition, neurophysiology), using different animal models (human and non-human), and different experimental methods (real and virtual environments), in order to provide a synthetic view on this issue, and to establish future goals of common interest. We focus here on two aspects of three- dimensional space: surface properties (e.g., hills and valleys) and volumetric properties. Surface Properties A major constraint to terrestrial movement is represented by the inclination of the terrain. While a moderate hill can be a challenge to walk, a steep one can be dangerous and energetically depleting. Therefore, it is ecologically adaptive for our perceptual system to be extremely sensitive in estimating geographical slants. Recent research by Durgin’s lab has indeed shown that the coding of slant, and
['Daniele Nardi', 'Frank H. Durgin', 'Kj Jeffery', 'Steven M. Weisberg']
How Vertical Spaces Are Perceived and Represented