Postma, D.B.W. (2014) Direct perception of catchability: A Differential Analysis of Optical Variables that Might Inform About the Perceived Catchability of a Fly Ball. thesis, Human Movement Sciences.
Full text available on request.Abstract
Chapman (1968) postulated an information-based control strategy that would lead to successful interception of a fly ball. The Chapman strategy, also known as the Optical Acceleration Cancellation (OAC) strategy, holds that zeroing out Optical Acceleration will lead to successful interception of a projected fly ball. Although the OAC strategy has proven to be quite successful in capturing the characteristics of locomotor patterns of fielders running to catch a fly ball, the strategy appears to be at odds with the theory of affordances. Affordances appear to have no part in guiding locomotion from an information-based control perspective. Though, control of everyday actions appears to be influenced by the perception of what is afforded (Fajen, 2007). The current study will examine what optical information is likely to be used by fielders to perceive the affordance for catchability. This is a first and necessary step in understanding the role of affordances in locomotor control in catching fly balls. Semi-professional baseball players were required to catch fly balls projected along the sagittal plane. Some fly balls were projected within their locomotor reach, whereas others were projected beyond their locomotor reach. Participants were instructed to call ‘no’ the instant they perceived a ball to be uncatchable. Using an HD-camera, positioned perpendicular to the plane of ball projection, we could establish different optical relations, such as Tau, Optical Acceleration and Image Velocity Ratio. The power, in predicting catchability, was assessed for each of the selected optical relations. Results show that a fractional derivative of Optical Position (i.e. !!.!(!) !!!.! ) is most likely to be used by fielders to assess catchability. Present findings provide an exiting entry for establishing the relation between the affordance and control aspects of running to catch a fly ball. KEYWORDS: Information-Based Control, Affordance-Based Control, Outfielder Problem, Perception - Action
| Item Type: | Thesis (UNSPECIFIED) |
|---|---|
| Supervisor name: | Zaal, dr. ir. F.T.J.M. |
| Faculty: | Medical Sciences |
| Date Deposited: | 06 Apr 2022 08:07 |
| Last Modified: | 06 Apr 2022 08:07 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/3047 |
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