Visual perception of lifted weight from kinematic and static (photographic) displays.

Observers of patch-light videotape displays can reliably discriminate levels of lifted weight; accuracy of judgments sometimes approximates that achieved when the observers themselves lift weighted boxes. Results of 6 studies reveal impressive levels of visual weight discrimination based on static displays (photographs) of certain action phases sampled from videos of entire lifting-carrying events. Slow and controlled actions (e.g., walking, placing box on table) supported optimum weight discrimination for both photographic and video displays, whereas the action of lifting a box yielded high levels of discrimination only for video displays. Static and kinematic specification of dynamics, as well as the work by painters and photographers to depict humans and other animals in action, is discussed.