Enhanced Memory for Scenes Presented at Behaviorally Relevant Points in Time

What determines whether a scene is remembered or forgotten? Our results show how visual scenes are encoded into memory at behaviorally relevant points in time

Mean recognition task accuracy for Experiments 1 and 2.

<p>Gray bar: results from Experiment 1 where there was no central fixation task. Recognition accuracy was not significantly different from chance performance, 51.32%±4.03%, <i>t</i>(11) = 0.3079, <i>p</i> = 0.7639. Black bar: results for test scenes presented behind black distractor letters in the target detection task in Experiment 2. Recognition accuracy was again not significantly different from chance performance, 52.49%±1.66%, <i>t</i> = 0.5951, <i>p</i> = 0.5638. White bar: results for scenes presented concurrently with white target letters in the target detection task in Experiment 2. Recognition accuracy was 67.21%±3.82%. A paired-samples <i>t</i> test revealed a significant difference between recognition task accuracy for test scenes that had been previously presented with black distractor letters versus white target letters, suggesting that scenes presented concurrently with white target letters were remembered better, <i>t</i>(10) = 2.746, <i>p</i> = 0.021. Error bars represent s.e.m. (*<i>p</i><0.05).</p

Mean recognition task accuracy for Experiment 4.

<p>Photos behind black distractors represent trials where the tested scene matched one of the scenes presented concurrently with a black letter during the RSVP stream. Conversely, photos behind white targets represent trials where the tested scene matched the scene presented concurrently with the white target letter during the RSVP. Displays were identical to Experiment 2; however, participants were instructed to direct their attention to the letters at fixation but only perform the recognition memory task. Given that the white letter serves as a perceptually novel event, one might expect enhanced performance for scenes presented concurrently with the novel event. However, recognition performance was at chance for both test scenes presented concurrently with black distractor letters and with novel white letters, <i>t</i>(14) = 0.6798, <i>p</i> = 0.5077, and <i>t</i>(14) = 0.8373, <i>p</i> = 0.4165, respectively. A paired-samples <i>t</i> test revealed no significant differences for test scenes presented concurrently with black letters (52.89%±1.33%) and novel white letters (53.13%±3.96%), <i>t</i>(14) = 0.1494, <i>p</i> = 0.8834, suggesting that the enhanced performance in prior experiments was not simply due to the perceptual novelty of the physical stimulus.</p

Mean recognition task accuracy for Experiment 3.

<p>Photos presented with baseline tones represent trials where the tested scene matched a scene that was presented concurrently with baselines tones in the RSVP stream. Conversely, photos presented concurrently with target tones represent trials where the tested scene matched the scene that was presented with the unique tone in the RSVP stream. In the dual-task condition, recognition accuracy for photos presented concurrently with baseline tones was 53.59%±1.65%, while recognition accuracy for photos presented concurrently with target tones was 64.78%±3.69%. A <i>t</i> test reveals that recognition accuracy for photos presented concurrently with baseline tones was not significantly higher than chance levels, <i>t</i>(10) = 0.7290, <i>p</i> = 0.4827. A paired-samples <i>t</i> test revealed a significant difference between recognition task accuracy for test scenes that had been presented concurrently with baseline tones versus target tones, suggesting that scenes presented concurrently with target tones were better encoded into memory, <i>t</i>(10) = 3.573, <i>p</i> = 0.005. Error bars represent s.e.m. (**<i>p</i><0.01).</p