Sensory memory of multi-stable displays: memory mechanisms are used to resolve ambiguity, not to stabilize perception

Publication Type:

Conference Paper

Source:

Vision Sciences Society 13th Annual Meeting (2014)

Abstract:

<p>Multi-stable displays are ambiguous visual displays that have several comparably plausible interpretations. When presented continuously, their appearance reverses spontaneously from time to time. When presented intermittently (blank intervals &gt;1 s), the appearance stabilizes, revealing the existence of an implicit visual memory (“sensory memory”) for multi-stable appearance. What function does this “sensory memory” subserve, if any? Typically, it is assumed that its function is to ensure continuity of vision during interruptions (“stabilization of perception” hypothesis). We propose an alternative hypothesis: Memory mechanisms are transiently engaged to accumulate sensory evidence and resolve perception of challenging visual displays (“resolution of ambiguity” hypothesis). In this case, an implicit visual memory trace is a mere epiphenomenon left by an earlier interaction between perception and memory. These two hypotheses make different predictions for the contents of visual memory: “Stabilization” predicts that it should hold the most recent appearance of a display, whereas “resolution” predicts that it should hold the initial appearance when the perception was established (shortly after the stimulus onset). To distinguish between these possibilities, we used a rotationally asymmetric structure-from-motion (SFM) object, the configuration (and dominant perceptual appearance) of which changed continuously during viewing episodes (1000 ms duration). After a blank interval (1000 ms duration), we presented an ambiguous probe display, at an orientation that corresponded to one of the configurations viewed earlier. We used selective adaptation procedure [Pastukhov, Füllekrug, &amp; Braun (2013) AP&amp;P, 75(6)] to determine the contents of the sensory memory and to infer the time instant when it was induced. We find that memory contents corresponds to perceptual state of SFM object at ~120 ms after onset. We conclude that lingering visual memory trace reflects an earlier transient engagement of memory mechanisms that were recruited to accumulate sensory evidence, assisting sensory regions in resolving perception of challenging (ambiguous) displays.</p>