Transitions between Central and Peripheral Vision Create Spatial/Temporal Distortions: A Hypothesis Concerning the Perceived Break of the Curveball

Abstract

BackgroundThe human visual system does not treat all parts of an image equally: the central segments of an image, which fall on the fovea, are processed with a higher resolution than the segments that fall in the visual periphery. Even though the differences between foveal and peripheral resolution are large, these differences do not usually disrupt our perception of seamless visual space. Here we examine a motion stimulus in which the shift from foveal to peripheral viewing creates a dramatic spatial/temporal discontinuity.Methodology/Principal FindingsThe stimulus consists of a descending disk (global motion) with an internal moving grating (local motion). When observers view the disk centrally, they perceive both global and local motion (i.e., observers see the disk's vertical descent and the internal spinning). When observers view the disk peripherally, the internal portion appears stationary, and the disk appears to descend at an angle. The angle of perceived descent increases as the observer views the stimulus from further in the periphery. We examine the first- and second-order information content in the display with the use of a three-dimensional Fourier analysis and show how our results can be used to describe perceived spatial/temporal discontinuities in real-world situations.Conclusions/SignificanceThe perceived shift of the disk's direction in the periphery is consistent with a model in which foveal processing separates first- and second-order motion information while peripheral processing integrates first- and second-order motion information. We argue that the perceived distortion may influence real-world visual observations. To this end, we present a hypothesis and analysis of the perception of the curveball and rising fastball in the sport of baseball. The curveball is a physically measurable phenomenon: the imbalance of forces created by the ball's spin causes the ball to deviate from a straight line and to follow a smooth parabolic path. However, the curveball is also a perceptual puzzle because batters often report that the flight of the ball undergoes a dramatic and nearly discontinuous shift in position as the ball nears home plate. We suggest that the perception of a discontinuous shift in position results from differences between foveal and peripheral processing.

The Conformal Camera in Modeling Active Binocular Vision

“…These different roles, very likely, involve different image processing principles [31,32]. An example of the separation in foveal and peripheral processing is explained in [31] in the context of curve balls in baseball. Often, batters report that balls undergo a dramatic and nearly discontinuous shift in their position as they dive in a downward path near home plate.…”

“…This shift in the ball's position occurs when the image of the ball passes the boundary on the retina between these two regions. The authors argue in [31] that this phenomenon is a result of the differences between foveal and peripheral processing.…”

Unifying account of visual motion and position perception

“…This is complicated by the fact that local motion signals can result from a combination of motions (of which object translations are only one) (15,16). A flying, rotating soccer ball provides a prototypical example of this problem (Fig.…”

Local form–motion interactions influence global form perception

“…As such, neural mechanisms that process the relative positions of the elements independently of their apparent motion may offset the mechanisms underlying the distortions that we report here. The relatively small distortion reported here suggests that these sources of positional information get integrated with local velocity information (De Valois & De Valois, 1988;Shapiro et al, 2010;Tse & Hsieh, 2006;Whitney, 2002;Whitney et al, 2003). It has been demonstrated that V4 is a site for the integration of many types of visual information (Desimone & Schein, 1987).…”

“…Specifically, the perceived speed of an object made up of perceptually grouped elements is dictated by the overall shape of the grouped object rather than by the speeds of the local elements (Caplovitz & Tse, 2007;Kohler et al, 2009). In addition, the perceived position of a drifting Gabor pattern can be influenced by the speed and direction of the drift (De Valois & De Valois, 1988;Shapiro, Lu, Huang, Knight, & Ennis, 2010;Tse & Hsieh, 2006). Moreover, Whitney et al demonstrated that these driftposition interactions lead to a perceived boundary shift for objects formed from drifting Gabors.…”