Kimberly W. Wong¹, Aalap D. Shah¹, Brian Scholl¹; ¹Yale University

We typically think of visual perception as providing us with representations of our present local environments. But vision may also sometimes represent the causal *past*, extracting how those environments got to be that way--as when a shape with a jagged 'bite' is represented as the full (unbitten) shape to which an event (biting) occurred. Here we suggest that this perception of 'causal history' is more prevalent than previously suspected, due to intuitive physics. In a stack of blocks (or books, or dishes), for example, gravity entails that the bottom object was placed before higher objects. Here we show that such 'historical' relationships are spontaneously extracted during passive viewing, and influence perception in surprising ways. Observers viewed a table on which a stack of two blocks appeared, (1) all at once, (2) with the bottom block appearing first, or (3) with the top appearing first--and they simply reported on each trial whether the blocks appeared simultaneously or sequentially. We reasoned that possibility (3) might be less naturally perceived, since it violates the causal history mandated by the underlying intuitive physics. And indeed: when the bottom block appeared first, observers reliably perceived this sequential presentation; but when the top block appeared first, they were more likely to mistakenly perceive that blocks had appeared simultaneously--as if the actual temporal offset and the gravity-inspired prior effectively cancelled out. In fact, observers were more accurate for towers built 'from the ground-up' than for actual simultaneous presentations (which were often misperceived as sequential). And these effects seemed specific to gravity-based intuitive physics, since they disappeared when the same stimuli appeared to be lying flat on the table. These results collectively show how visual processing extracts causal history as a result of intuitive physics, and how such representations influence the perception of temporal order.