False memories for missing aspects of traumatic events.

Can people come to remember an event as being more traumatic than they initially experienced? Participants watched a highly structured and emotionally disturbing film depicting a car accident in which five people, including a baby, are killed. We broke the film down into a series of short clips; some of which we removed. Later, we tested participants' memory for what they had and had not seen. While participants were highly accurate identifying what they had and definitely had not seen, they also falsely claimed to have seen 26% of the missing clips, clips that fitted with the film but were removed before screening. Moreover, participants were particularly likely to recall the missing clips that were considered to be the most critical and traumatic. Importantly, they did so with high confidence. We discuss both intentional and unintentional recall mechanisms that may promote the observed memory distortion.