Do you need a "flash" to form a flashbulb memory?

On January 16, 1991, students encoded an «ordinary event» as part of a demonstration on flashbulb memories and completed a questionnaire modeled after Christianson (1989). By coincidence, the bombing of Iraq began the same day. A similar questionnaire asking about memory for the bombing was given to students 2 days later. In April 1991 and January 1992, both questionnaires were again completed, allowing comparisons of the students' memories for the 2 events. Although few differences appeared in the accuracy of the 2 memories over the intervals, confidence levels for the memories surrounding the bombing were significantly higher. Furthermore, retention and confidence did not differ from April 1991 to January 1992