The effects of age in the discrimination of curved and linear paths

摘要

Previous research has found that younger observers show a greater accuracy in detecting curved trajectory of moving objects when a three-dimensional background was present (Gillespie & Braunstein, VSS 2009). The current study examined age-related differences in detecting curved trajectories of moving objects. Younger and older observers viewed two displays in which a ball moved towards the observer. In one of the displays the ball moved along a linear path, while in the other display the ball moved in an upwards arc along one of three curved paths. Curvature of the path was indicated by projected velocity information, size change information, or by both types of information. In addition to age, four independent variables were manipulated: the background information (3D scene vs. uniform background), the information indicating the curved trajectory (velocity, size, or both), the order of the trajectory (linear first vs. curved first), and the curvature of the curved trajectory (three levels). The task was to indicate which display simulated a curved trajectory. A three way interaction was found between age, background information, and information indicating the curved trajectory. When background information was present, the performance of older observers was similar to that of younger observers when only velocity information was available and when both size and velocity information was available. Accuracy was at chance for both age groups when only size change information was provided. When uniform background information was given, this trend was the same for younger observers. However, for older observers, performance was at chance level regardless of what type of information was available. These results show the importance of velocity information when detecting forward moving curved paths. The results also suggest that older individuals in particular use ground plane information to determine curved paths.