Visual routines for detecting causal interactions are tuned to motion direction

Abstract

AbstractDetecting causal relations structures our perception of events in the world. Here, we determined whether generalized or specialized visual routines underly the perception of causality by assessing the adaptability of specific features in launching events of simple geometric shapes. After prolonged exposure to causal launch events (the adaptor) defined by a particular set of features (i.e., a particular motion direction, motion speed, or feature conjunction), observers were less likely to see causal interactions in subsequent ambiguous test events. We assessed whether this negative aftereffect transfers to test events with a new set of feature values that were not presented during adaptation. Processing in specialized (as opposed to generalized) visual routines predicts that the transfer of adaptation depends on the feature-similarity of the adaptor and the test event. We show that negative aftereffects do not transfer to unadapted launch directions. Crucially, adaptation was contingent on the causal impression in launches as demonstrated by a lack of adaptation in non-causal control events. In contrast, adaptation to launches with a particular motion speed transferred also to a different speed. Moreover, adaptation based on feature conjunctions (color and launch direction) revealed that launch direction trumps the feature identity of the object for causal perception; the adaptation transferred across colors if the test event had the same motion direction as the adaptor. In summary, visual adaptation allowed us to carve out a visual feature space underlying the perception of causality and revealed specialized visual routines that are tuned to a launch’s motion direction.Significance statementWe used visual adaptation to carve out a visual feature space that is critical for detecting collisions in launching events. Observers were less likely to report perceiving a collision after the repeated viewing of launches. Importantly, observers’ perception of collisions in the opposite direction as the adaptor were not affected by the adaptation. However, provided the test stimulus had the adapted direction of motion, the speed or the color of the objects involved in the launching event did not need to be the same as during adaptation to show the negative aftereffect. Thus, visual routines underlying the detection of causal interactions are selective for motion direction, therefore providing evidence that the perception of causality relies on low-level perceptual processes.