Consistency of flashbulb memories of September 11 over long delays: Implications for consolidation and wrong time slice hypotheses

The consistency of flashbulb memories over long delays provides a test of theories of memory for highly emotional events. This study used September 11, 2001 as the target event, with test–retest delays of 2 and 3 years. The nature and consistency of flashbulb memories were examined as a function of delay between the target event and an initial test (1–2 days or 10–11 days), and the number of initial tests (1 or 2) in 124 adults from the general population. Despite a reliable drop in consistency over the long delay periods, mean consistency scores were fairly high and the number of memories classed as ‘major distortions’ was remarkably low in both 2003 (9%) and 2004 (7%). The results concerning memory fluctuations across the re-tests and the qualitative analysis of ‘major distortions’ are consistent with the wrong time slice hypothesis which explains the development of distortions by hearing the news from multiple sources on the day of the flashbulb event [Neisser, U., & Harsch, N. (1992). Phantom flashbulbs: False recollections of hearing the news about Challenger. In: E. Winograd, & U. Neisser (Eds.), Affect and accuracy in recall: Studies of “flashbulb memories” (pp. 9–31). Cambridge: Cambridge University Press]. However, no support was obtained for the consolidation hypothesis [Winningham, R. G., Hyman, I. E., & Dinnel, D. L. (2000). Flashbulb memories? The effects of when the initial memory report was obtained. Memory, 8, 209–216]: memories of participants who were initially tested 10–11 days after September 11 were not more consistent than memories of participants tested 1–2 days after the event. In addition, the number of initial tests in September 2001 (one or two) and self-reported rehearsal did not have any beneficial effects on consistency. Together, these findings indicate that flashbulb memories may be formed automatically and consolidated fairly soon after an emotional event.