The generalized optic acceleration cancellation theory of catching.

Abstract

The generalized optic acceleration cancellation (GOAC) theory of catching proposes that the path of a fielder running to catch a ball is determined by the attempt to satisfy 2 independent constraints. The 1st is to keep the angle of elevation of gaze to the ball increasing at a decreasing rate. The 2nd is to control the rate of horizontal rotation necessary to maintain fixation on the ball. Depending on the lateral velocity of the ball relative to the fielder, this rate may be zero or constant at a negative or positive value. The authors show that a simulated fielder implementing the GOAC strategy follows a path indistinguishable from that of real fielders running to catch balls thrown on the same trajectories.

Evidence for a generic interceptive strategy

“…They presented a theory and simulated data that supported the idea that fielders catching baseballs headed to the side keep their gaze moving upward at a decreasing rate, thereby guaranteeing interception (McLeod et al, 2001(McLeod et al, , 2003(McLeod et al, , 2006. They also claimed, and showed, that fielders simultaneously move their gaze laterally, relative to the origin and at a constant rate.…”

“…A new strategy for catching baseballs has been described by McLeod et al (2003) and further described by McLeod et al (2006). They presented a theory and simulated data that supported the idea that fielders catching baseballs headed to the side keep their gaze moving upward at a decreasing rate, thereby guaranteeing interception (McLeod et al, 2001(McLeod et al, , 2003(McLeod et al, , 2006.…”

“…Although much of the evidence suggests that fielders do run so that increases McLeod & Dienes, 1996;McLeod et al, 2003McLeod et al, , 2006, one of the disadvantages is that controlling the velocity of the vertical optical angle in this way does not guarantee interception, which is geometrically guaranteed when fielders keep the tangent of (tan ) increasing at a constant rate (or maintaining constant acceleration of the ball) (Chapman, 1968). At angles near 30º, can be kept increasing at a constant rate to satisfy the requirement that tan increases at a constant rate, because tan (i.e., the law of small angles).…”

“…In the present study, we test whether humans catching Frisbees utilize the same simple viewer-based navigational heuristics that have been established for baseball and cricket fielders catching fly balls (McBeath, Shaffer, & Kaiser, 1995McLeod, Reed, & Dienes, 2001, 2006. When baseball outfielders run to catch fly balls, they use natural, geometrically invariant properties to optically maintain control over the ball.…”

“…It seems more likely that humans adopted an interception strategy for baseball that they evolved to take advantage of across a number of domains, and less likely that fielders have adopted a "baseball specific" (or "cricket specific") strategy. In this article, we examine whether a monotonically increasing LOT and a more recent proposal for catching fly balls (McLeod et al, 2006) are generic tracking strategies used by humans catching Frisbees in addition to catching fly balls. Before testing how well these two strategies can explain Frisbee-catching behavior, we first clarify the angular notation we use to describe patterns of instantaneous optical position and velocity for the LOT.…”