Humans show a gravitational advantage in perception: we are more precise at judging the speed of downwards-moving than upwards-moving objects, indicating that gravitational acceleration is an internalised prior. However, it is unclear whether this gravity prior is based on purely perceptual cues or whether it can incorporate semantic knowledge. Previous research has used only objects which are known to comply with gravity, possibly confounding semantic and perceptual cues. Here we have addressed this question by asking participants to judge the speed of objects that typically move coherently with gravity (ball) or against it (rocket). Our results showed a perceptual advantage for falling stimuli, irrespective of object identity, suggesting the gravity prior is based on perceptual cues.

人类在感知方面表现出重力优势：我们判断向下运动的速度比向上运动的物体更精确，这表明重力加速度是内在的先验。但是，目前尚不清楚该引力先验是否仅基于感知线索或它是否可以包含语义知识。先前的研究仅使用已知符合重力的物体，可能会混淆语义和感知线索。在这里，我们通过要求参与者判断通常随着重力（球）或逆着重力（球）相干运动的物体的速度解决了这个问题。我们的研究结果显示了跌倒刺激的感知优势，而与物体身份无关，这表明重力先验是基于感知线索的。