Caroline Myers¹ (), Peter Mazalik¹, Jonathan Flombaum¹, Justin Halberda¹; ¹Johns Hopkins University

A staggering example of apparent motion is the Ternus illusion: when two discs are shown side by side, and then shifted horizontally, the temporal gap between the successive presentations determines whether observers perceive element-wise or group motion. At long (20ms) intervals, group motion is perceived; at brief (0ms) intervals, element-wise motion is perceived. Will an object-file travel with our conscious percept, or will assignment prioritize spatiotemporal proximity? To test these possibilities, we exploited a well-known paradigm – the object-specific preview benefit (OSPB) – in which “previewing” information presented on one object results in faster and more accurate retrieval if the information later reappears on the “same” object relative to another object. If moving objects are defined by spatiotemporal proximity, an OSPB should not follow an object that appears to “jump” when element-wise motion is perceived. However, if the object file system tracks conscious perception, we should expect to see benefits at the “perceived” final position of the object. Observers viewed an apparent motion display consisting of three horizontally adjacent discs containing letters. Following a variable blank inter-stimulus interval, (0ms or 20ms), the discs reappeared shifted one position rightward, with a probe letter reappearing on either the same or different discs. Observers reported whether the probe contained the same letter shown at the beginning of the trial. Strikingly, observers’ reaction times and accuracy reflected a characteristic OSPB in accordance with the induced percept: participants retrieved the feature faster and more accurately both when the probed object appeared to translate (20ms intervals), as well as when it appeared to jump (0ms intervals). These results suggest that object identity is mapped across the perceived object motion path induced by the inter-stimulus interval, even if the induced motion path is not the shortest. Thus, in the Ternus display, object files mirror our conscious percepts.