Transformations of Visuospatial Images

Abstract

Transformations of visuospatial mental imagesHere are some simple instructions: "Close your eyes.Imagine you are standing in front of a pedestal facing a bust of William James. Imagine now that you have walked around the pedestal and are now viewing the bust from the side. Now, imagine that a motor is turning the bust, allowing you to view it from a range of angles. Finally, imagine that you reach out, pick up the bust, and turn it upside-down to look at the bottom."Most people report that they can follow such instructions, and doing so often results in phenomenal experiences that are vivid and faithful to reality-though the degree that this is the case varies among individuals (Isaac and Marks, 1994). The experiences evoked by instructions such as these are transformations of visuospatial images. They may not require explicit intentions to produce: Humans and other animals appear to construct and transform visuospatial representations to solve a range of everyday reasoning problems, including navigation, the making and using of tools, and construction. But what is the computational and neurophysiological nature of the representations involved? How are those representations transformed during explicit and implicit visuospatial imagery?There is now a body of theory and evidence speaking to each of these questions. The goals of this article are, first, to introduce a framework for thinking about visuospatial image transformations, and, second, to interpret the available data within that framework to provide current best answers to both questions. To do so, we first provide an overview of the phenomena constituting visuospatial imagery and then describe a framework for relating image transformations to the representations on which they operate. The rest of the article characterizes different types of image transformations and the relations among them. The article's major empirical claim is that two sorts of visuospatial transformations can be dissociated: transformations in which the representations of individual objects are updated relative to other spatial representations and transformations in which one's personal perspective is updated. These visuospatial transformations are characterized by different patterns of behavioral performance, different neural correlates, and different psychometric properties. 96Authors' Note: We would like to thank Ty Fagan for his assistance with the meta-analysis. We also thank Sarah Creem-Regehr, Nora Newcombe, Amy Shelton, Barbara Tversky, and Maryjane Wraga, whose thoughtful comments were extremely helpful in revising the article. The research of our laboratory described here was supported in part by the McDonnell Center for Higher Brain Function.

Imagined own-body transformations during passive self-motion

“…This finding suggests that spatial perspective taking involves the embodied transformation of one's body to adopt the imposed perspective. This 'embodied transformation account' is further supported by neuroimaging studies showing the involvement of motorrelated areas during perspective taking and indicating that spatial perspective taking involves comparable neural mechanisms that are involved in actual bodily movements as well (Vogeley et al, 2004;Wraga, Shephard, Church, Inati, & Kosslyn, 2005;Zacks & Michelon, 2005).…”

“…On this account, increased angular disparity between the actual and the imagined spatial perspective results in a stronger discrepancy between the physical and imagined egocentric reference frame, which is reflected in slower response times and higher error rates. This hypothesis accounts for the finding that response latencies and errors increase with increased angular disparity between the imagined and actual spatial perspective (Huttenlocher & Presson, 1979;Kozhevnikov & Hegarty, 2001;May, 2004;Zacks & Michelon, 2005) and that imagined rotations were found to be more difficult than imagined translations (Creem-Regehr, 2003;Rieser, 1989). That is, in the case of translation the conflict between the imagined and the actual egocentric perspective is smaller than in the case of rotation, thereby resulting in less errors.…”

“…The sensorimotor interference hypothesis is closely related to the suggestion that spatial perspective taking is an embodied process that involves a mental transformation of the observer's own body (Zacks & Michelon, 2005). More specifically, it has been proposed that spatial perspective taking involves a process of endogenous motor embodiment, in which a self-initiated emulation of a body movement is used to adopt the imposed perspective (Arzy, Thut, Mohr, Michel, & Blanke, 2006;Kessler & Thomson, 2010).…”

Egocentric and object-based transformations in the laterality judgement of human and animal faces and of non-corporeal objects

“…This indicates that one set of instructions spontaneously lead to two entirely different strategies, and highlights the importance of recognizing the often glossed over role of individual differences in cognitive strategy and motor imagery performance [47]. Notably, and in accord to other studies which included the spatial transformation of one self with respect to a model room [34] or the spatial transformation of a car and of one's own perspective [45], the typical psychophysical profile for response times (mental rotation function) was found for the objectbased group, but not the egocentric group.…”

“…We have attempted to deal with the first issue through the use of the semi-structured questionnaire to elicit feedback about the strategy used. To deal with the second issue, we have adopted the operational definitions described in the comprehensive review of Zacks and Michelon [47]. Hence, we use "egocentric transformation" to mean the localization of an object to one's own frame of reference, and "object-based transformation" to refer to the localization of an object relative to a complex of axes relative to the same object.…”