Interactions of form and motion in the perception of moving objects

This chapter covers a few highlights from the past 20 years of research demonstrating that there is ‘motion from form’ processing. It has long been known that the visual system can construct ‘form from motion.’ For example, appropriate dot motions on a two-dimensional computer screen can lead to a percept of, say, a rotating three-dimensional cylinder or sphere. Less appreciated has been the degree to which perceived motion follows from processes that rely upon rapid analyses of form cues. Percepts that depend on such form-motion interactions reveal that form information can be processed and integrated with motion information to determine both the perceived velocity and shape of a moving object. These integration processes must be rapid enough to occur in the brief period, probably less than a quarter of a second, between retinal activation and visual experience. Data suggest that global form analyses subserve motion processing in at least five ways (Porter et al., 2011). Here, we describe three examples in which the analysis of form significantly influences our experience of moving objects. The following examples have been chosen not only for their distinctiveness, but also to compliment other examples described in detail within other chapters of this book (Bruno & Bertamini, 2013; Herzog & Öğmen, 2013; Hock, 2013; Vezzani et al., 2013). First, we describe Transformational Apparent Motion, a phenomenon that reveals how form analyses permit the figural segmentation dedicated to solving the problem of figure-to-figure matching over time (Hsieh and Tse, 2006; Tse, 2006; Tse & Caplovitz, 2006; Tse & Logothetis, 2002). Secondly, we describe how the size and shape of an object can influence how fast it is perceived to rotate. These interactions reveal the way in which form analyses permit the definition of trackable features whose unambiguous motion signals can be generalized to ambiguously moving portions of an object to solve the aperture problem (Caplovitz et al., 2006; Caplovitz & Tse, 2007a,b). Finally, we describe a number of peculiar ways in which the motions of individual elements can interact with the perceived shape and motion of a global object constructed by the grouping of these elements. These phenomena reveal that the form analyses that underlie various types of perceptual grouping can lead to the generation of emergent motion signals belonging to the perceptually grouped object that appear to underlie the conscious experience of motion (Caplovitz & Tse, 2006, 2007b; Hsieh & Tse, 2007; Kohler et al., 2010; Kohler et al., 2009). OUP UNCORRECTED PROOF – FIRSTPROOFS, Mon Nov 03 2014, NEWGEN