Abstract
Perception often seems instantaneous, but the underlying reality is richer and stranger. Consider a post-cueing paradigm: multiple stimuli are presented briefly (as S1, at time t), and then after they disappear one of them is highlighted (at time t+1) by a cue (S2). Intuitively, it would seem impossible for S2 to influence the subjective perception of S1 — since by t+1 it should be “too late”. Yet this is precisely what can happen: S2 may enhance the perception of S1 (as in retrospective triggering of awareness), or may degrade it (as in object substitution masking) — a phenomenon known as *postdiction*. In past studies, the S2 cue has nearly always altered the perception of a *static* property of S1 (e.g. its shape or orientation). Here, in contrast, we ask whether postdiction is sophisticated enough to enhance the perception of temporal order itself. On each trial, observers saw two outlined circles. Four unique colors then appeared briefly — two at a time, one in each circle. Afterward, an arrow appeared, to highlight one of the (again-empty) circles as the ‘target’, and observers simply reported which two colors had appeared (and in what order) inside the target circle. Critically, a task-irrelevant post-cue also appeared on some trials: after the colors had disappeared (but before the target was identified), a randomly selected circle flashed momentarily. This gave rise to a robust postdictive performance enhancement: observers were more accurate at identifying each target color — and the order in which they appeared — when the target circle happened to flash (compared to when the non-target circle flashed, or when there was no flash). Thus postdiction can not only alter our perception of an object’s static features, but can also enhance our temporal experience of the world.