Body movement perception is shaped by both generic and actor-specific models of human bodies

Body movement perception is shaped by knowledge of the human body biomechanics. Apparent motion from rapidly alternating pictures follows the shortest path between two body postures only if it is biomechanically plausible. And although we tend to perceive a moving body part as slightly shifted forward along its trajectory, this extrapolation is absent (or reduced) when the biomechanical constraints make continued movement unlikely. The received view is that perception is shaped by a model of the observer's own body. Here, we present three lines of evidence challenging this view. First, we report the typical influence of knowledge of the upper-limb biomechanics on apparent movement perception and perceptual extrapolation in two individuals born without limbs (Experiments 1 and 2). Second, we report that these effects are independent of the observers' own flexibility (Experiment 3). Third, we show that perception is influenced by knowledge of actor-specific biomechanics (Experiments 4-8). We conclude that body movement perception relies on visually acquired models of both generic and actor-specific body biomechanics. (PsycInfo Database Record (c) 2026 APA, all rights reserved).