Form features provide a cue to the angular velocity of rotating objects.

Abstract

As an object rotates, each location on the object moves with an instantaneous linear velocity dependent upon its distance from the center of rotation, while the object as a whole rotates with a fixed angular velocity. Does the perceived rotational speed of an object correspond to its angular velocity, linear velocities, or some combination of the two? We had observers perform relative speed judgments of different sized objects, as changing the size of an object changes the linear velocity of each location on the object’s surface, while maintaining the object’s angular velocity. We found that the larger a given object is, the faster it is perceived to rotate. However, the observed relationships between size and perceived speed cannot be accounted for simply by size-related changes in linear velocity. Further, the degree to which size influences perceived rotational speed depends on the shape of the object. Specifically, perceived rotational speeds of objects with corners or regions of high contour curvature were less affected by size. The results suggest distinct contour features, such as corners or regions of high or discontinuous contour curvature, provide cues to the angular velocity of a rotating object.

Spatiotemporal Form Integration: Sequentially presented inducers can lead to representations of stationary and rigidly rotating objects

“…These features also play an important role in determining the speed of moving objects (Blair, Goold, Killebrew, & Caplovitz, 2014; Caplovitz, Hsieh, & Tse, 2006; Caplovitz & Tse, 2007; Ullman, 1979). Specifically, the angular velocity of rotating objects is more accurately estimated when they contain salient contour regions such as contour discontinuities and regions of high contour curvature (Blair et al, 2014).…”

“…These features also play an important role in determining the speed of moving objects (Blair, Goold, Killebrew, & Caplovitz, 2014; Caplovitz, Hsieh, & Tse, 2006; Caplovitz & Tse, 2007; Ullman, 1979). Specifically, the angular velocity of rotating objects is more accurately estimated when they contain salient contour regions such as contour discontinuities and regions of high contour curvature (Blair et al, 2014). This has important implications for perceiving moving objects under conditions of occlusion, especially considering the finding that occluded regions of objects are perceived to move more slowly (Palmer & Kellman, 2014) and such features may aid in extracting an accurate motion signal.…”

Towards a unified perspective of object shape and motion processing in human dorsal cortex

“…In some cases, for example, larger objects appear to move slower than smaller ones (Kohler et al, 2009, 2014; Verghese & Stone, 1996). However, in the case of rotational motion, the opposite is true: large object appear to rotate faster than small ones and moreover the degree to which size influences perceived rotational speed is itself mediated by the shape of the object (Blair, Goold, Killebrew & Caplovitz, 2014). The perceived speed of an object can also be influenced by its orientation relative to the direction of motion with objects elongated in the direction of motion appearing to move faster than ones moving in a perpendicular direction (Krolik, 1934; McCarthy, Cordeiro, & Caplovitz, 2012; Metzger, 1936; Or, Khuu, & Hayes, 2010; Pavan, Bimson, Gall, Ghin, & Mather, 2017; Porter, Caplovitz, Kohler, Ackerman, & Peter, 2011; Series, Georges, Frégnac, & Lorenceau, 2002).…”

Color synesthesia improves color but impairs motion perception

“…Not only does form processing play an important role in grapheme-color synesthesia, but it also contributes to many aspects of motion perception [8]. For example, the size and shape of an object can greatly influence the way it is perceived to move [9] and conversely, the motion of an object can influence its perceived shape. Could it be the case that the color-form and color-motion mechanisms that manifest in color synesthesia mediate interactions between form and motion?…”