Long-lasting effects of briefly flashed words and pseudowords in ultrarapid serial visual presentation

Our ability to identify even complex scenes in rapid serial visual presentation (RSVP) is astounding, but memory for such items seems lacking. Rather than pictures, we used streams of more than 200 verbal stimuli, rushing by on the screen at a rate of more than 12 items per second while participants had to detect infrequent names (Experiments 1 and 2) or words written in capitals (Experiment 3). By direct and indirect tests, we investigated what is remembered of these masses of task-irrelevant distractor words and pseudowords embedded in an RSVP stream. Lexical decision, the indirect test applied either immediately after each stimulus train or with a delay, revealed strong long-term priming effects. Relative to stimuli not shown before, lexical decisions were faster and more accurate to words but slower to pseudowords. The size of these effects mirrored how often words and pseudowords had occurred in a stream, suggesting that memory traces are strengthened with successive presentations and survive for several minutes at least. Moreover, in a direct test (old-new categorization), words as well as pseudowords benefited from prior occurrence in an RSVP stream if they had occurred more than once. These findings parallel recent physiological and behavioral evidence for memory consolidation of distractor pictures in RSVP and highlight that, despite huge numbers of interfering stimuli, distractor words and pseudowords exhibit long-lasting memory effects. Consolidation seems to progress at higher cognitive levels at the same time that subsequent stimuli are perceptually processed.