Abstract
Visual processing recovers not only low-level properties such as color and motion, but also seemingly higher-level properties such as causality. In Michotte's 'launching effect', for example, an object (A) moves toward a stationary second object (B) until they are adjacent, at which point A stops and B starts moving in the same direction. In this situation, observers have a visceral visual impression that B's motion was caused by A's impact. And among the evidence that this truly reflects visual processing (as opposed to higher-level judgment) is the discovery that causal launching supports retinotopically specific adaptation (Rolfs et al., 2013, Current Biology): viewing causal launching causes a later ambiguous event (in which A and B may overlap to some degree before A stops and B starts moving) to be perceived as non-causal 'passing' – but only if the two events occur in the same retinal location. Does this reflect the detection of some unitary phenomenon of causality, or might vision extract multiple distinct forms of causal perception (as explored by Komsinky et al., 2017, Psychological Science)? Here we use adaptation to ask whether launching is a fundamentally different category from entraining – which is superficially identical to launching, except that A continues to move along with B once they make contact. In contrast to other sorts of causal events (Kominsky & Scholl, 2016, VSS), retinotopically specific adaptation did not transfer between launching and entraining. In particular, adapting to entraining events had no effect on the subsequent perception of ambiguous events as involving launching or passing. We conclude that there are indeed fundamentally distinct categories of causal perception in vision. Furthermore, this emphasizes the sensitivity of the adaptation effect, which is specific enough to distinguish not only between causal and non-causal events, but between different categories of causal events.
Meeting abstract presented at VSS 2018