Zago Myrka, La Scaleia Barbara, Miller William L, Lacquaniti Francesco
Laboratory of Neuromotor Physiology, Santa Lucia Foundation, Rome, Italy.
J Vis. 2011 Sep 20;11(10):13. doi: 10.1167/11.10.13.
Dealing with upside-down objects is difficult and takes time. Among the cues that are critical for defining object orientation, the visible influence of gravity on the object's motion has received limited attention. Here, we manipulated the alignment of visible gravity and structural visual cues between each other and relative to the orientation of the observer and physical gravity. Participants pressed a button triggering a hitter to intercept a target accelerated by a virtual gravity. A factorial design assessed the effects of scene orientation (normal or inverted) and target gravity (normal or inverted). We found that interception was significantly more successful when scene direction was concordant with target gravity direction, irrespective of whether both were upright or inverted. This was so independent of the hitter type and when performance feedback to the participants was either available (Experiment 1) or unavailable (Experiment 2). These results show that the combined influence of visible gravity and structural visual cues can outweigh both physical gravity and viewer-centered cues, leading to rely instead on the congruence of the apparent physical forces acting on people and objects in the scene.
处理倒置的物体既困难又耗时。在对于定义物体方向至关重要的线索中，重力对物体运动的可见影响受到的关注有限。在这里，我们操纵了可见重力与结构视觉线索之间以及它们相对于观察者方向和物理重力的对齐方式。参与者按下一个按钮触发一个击球器去拦截一个由虚拟重力加速的目标。一个析因设计评估了场景方向（正常或倒置）和目标重力（正常或倒置）的影响。我们发现，当场景方向与目标重力方向一致时，拦截显著更成功，无论两者是直立还是倒置。这与击球器类型无关，并且当向参与者提供（实验1）或不提供（实验2）表现反馈时都是如此。这些结果表明，可见重力和结构视觉线索的综合影响可以超过物理重力和以观察者为中心的线索，从而导致人们转而依赖作用于场景中人和物体的表观物理力的一致性。
