Relative Throw-ability of Objects of Varying Size and Weight Is Perceivable As Revealed By Magnitude Estimation Methods
36.423, Sunday, May 12, 2:45 - 6:45 pm, Orchid Ballroom
Todd Mirich1, Qin Zhu1, Geoffrey Bingham2; 1Division of Kinesiology and Health, University of Wyoming, 2Department of Brain and Psychological Research, Indiana University
Introduction Bingham et al (1989) found that throwers could perceive the optimal weights for objects of given sizes to be thrown to maximum distances. This has been confirmed numerous times (Zhu et al, 2008, 2009, 2011, 2012). Bingham et al. also speculated that the relative throw-ability among all object sizes and weights might be perceivable, but this had not been tested until now. Methods 21 skilled throwers were blindfolded and asked to judge the throw-ability of 24 objects (3 sizes and 8 weights in each size) by hefting objects in the throwing hand. Participants were assigned randomly to one of three groups. Each group selected the optimal object in one of the sizes. The selection was used as a reference (magnitude = 100). Participants compared all remaining objects with the reference to judge relative magnitudes of throw-ability. Results A mixed design ANOVA was performed on judged magnitudes, and no main effect was found for group, but the interactions with weight (F14,126 = 3.5, P <0.001) and size by weight (F28,252 = 2.2, P <0.001) were significant as were size (F2,36 = 13.2 p <0.001) and size by weight (F14,252 = 21.2 p <0.001). Results for COV were closely related. Post-hoc analyses showed different weights were rated highest within each size with the least variability. This pattern of judgments was similar to that in skilled long distance throwing using the same objects (Zhu & Bingham, 2008). For instance, 1 balls were rated higher and thrown farther than 6 ones. Heaviest weights in 1" and middleweights in 6" were rated highest and thrown farthest. Conclusion The speculation of Bingham et al. was confirmed by the current study, which implies the general mapping from throwing performance to perception of the relevant affordance.