Figure 1.

One-shot change detection paradigms. A scene (S) was presented for 3000 ms, followed by a blank screen (250 ms), a very brief presentation (150 ms) of either an identical or altered image (S or S′), and another blank screen (2500 ms). Participants held central fixation while trying to detect whether or not a single change occurred in the scene. (A) LTM-guided condition: Participants viewed scenes for which they had previously learned the location of changes. Participants were instructed to covertly direct attention to the remembered location of the potential change; no explicit spatial cue was provided. (B) STIM-guided condition: Participants viewed scenes that they had previously studied without exposure to scene changes. A red and white square explicitly cued the location of the potential scene change, and then disappeared prior to the image change. Note that the white circle was used in this figure for illustration purposes to highlight the scene change, but no such stimulus appeared on the images.