Learning to visually perceive the relative mass of colliding balls in globally and locally constrained task ecologies.
David M. Jacobs, Sverker Runeson, Claire Farley Michaels · Journal of Experimental Psychology Human Perception & Performance · 2001
Novice observers differ from each other in the kinematic variables they use for the perception of kinetic properties, but they converge on more useful variables after practice with feedback.The colliding-balls paradigm was used to investigate how the convergence depends on the relations between the candidate variables and the to-be-perceived property, relative mass.Experiment 1 showed that observers do not change in the variables they use if the variables with which they start allow accurate performance.Experiment 2 showed that, at least for some observers, convergence can be facilitated by reducing the correlations between commonly used nonspecifying variables and relative mass but not by keeping those variables constant.Experiments 3a and 3b further demonstrated that observers leam not to rely on a particular nonspecifying variable if the correlation between that variable and relative mass is reduced.Research has shown that humans can visually perceive kinetic properties of their environments such as the weight of lifted boxes (Runeson & Frykholm, 1983), the peak force exerted by bimanual pullers (Michaels & de Vries, 1998), and the relative mass of colliding balls (Runeson, 1995).Given that the ambient optic array comprises only kinematic variables (e.g., velocities and angles), kinematic variables must form a basis for the perception of kinetic properties.The bulk of research on the visual perception of kinetic properties has been carried out in the colliding-balls paradigm.In this paradigm, observers are asked to judge which of two colliding balls is the heavier or, more recently (Jacobs, Michaels, & Runeson, 2000), to make quantitative estimates of mass ratios.Runeson (1995) showed that the mass ratio of colliding balls is specified by, among other kinematic patterns, the relative amount of velocity change.