A distributed movement is complex, but, as Diaz's second experiment indicates, some people may be using it however unconsciously to inform their judgment as to which direction the ball will go.
In his second experiment, Diaz played an animation of the motion capture data to a group of 31 subjects, and asked the subjects to pick which direction they thought the ball would go. In the animation, each body joint is represented by a dot, and movement of the body is easily recognizable as such. The animation runs from the standing-start until the foot reaches the ball, at which point the screen goes black and subjects pressed a button to the left or right of the screen, indicating which direction they thought the ball had gone.
Among his 31 subjects, all of whom were novices to the activity, 15 were not able to score above chance (50/50), even when given one-half second after the scene to ponder the outcome. Sixteen, however, did perform better than chance.
Diaz then looked for relationships between successful judgments on ball direction and each of the "local" and "distributed" movements he had tracked. His analysis revealed strong correlations between the two "local" and two of the three "distributed movements" that were reliable indicators of kick direction.
"The question is, knowing these potential sources of reliable information, what do people actually use?" Diaz said. "I found four reliable sources that were well correlated with subjects' judgments."
Another finding, he said, is that the 16 successful subjects waited longer than the 15 unsuccessful subjects to make their choices (if the half-second elapsed without a response from the subject, no result was entered).
"There is a clear relationship between response timing and performance," Diaz said.
Diaz said his findings have set the stage for further exploration. He would like to creat
|Contact: Mary Martialay|
Rensselaer Polytechnic Institute