Abstract
In addition to detecting "low-level" features like shape, color, and movement, the human visual system perceives certain "higher-level" properties of the environment, like cause-and-effect interactions. The strongest evidence that we have true causal perception and not just inference comes from the phenomenon of retinotopically specific visual adaptation to launching, which shows that launching events have specialized processing at a point in the visual system that still uses the surface of the retina as its frame of reference. Using this paradigm, we show that the visual system adapts to two distinct causal features found in different types of interaction: a broad "launching-like" causality that is found in many billiard-ball-like collision events including "tool-effect" displays, "bursting," and event "state change" events; and an "entraining" causality in events where one object contacts and then moves together with another. Notably, adaptation to entraining is not based on continuous motion alone, as the movement of a single object does not generate the adaptation effect. These results not only demonstrate the existence of multiple causal perceptions, but also begin to characterize the precise features that define these different causal event categories in perceptual processing.