decline 32 months after the event. While the accuracy of flashbulb memories may not be stable over time, confidence of the accuracy of a flashbulb memory appears to be stable over time. A study conducted on the bombing in Iraq and a contrasting ordinary event showed no difference for memory accuracy over a year period; however, participants showed greater confidence when remembering the Iraqi bombing than the ordinary event despite no difference in accuracy. Likewise, when memories for the 9/11 World Trade Center attack were contrasted with everyday memories, researchers found that after one year, there was a high, positive correlation between the initial and subsequent recollection of the 9/11 attack. This indicates very good retention, compared to a lower positive correlation for everyday memories. Participants also showed greater confidence in memory at time of retrieval than time of encoding. Relation to autobiographical memory Some studies indicate that flashbulb memories are not any more accurate than other types of memories. It has been reported that memories of high school graduation or early emotional experiences can be just as vivid and clear as flashbulb memories. Undergraduates recorded their three most vivid autobiographical memories. Nearly all of the memories produced were rated to be of high personal importance, but low national importance. These memories were rated as having the same level of consequentiality and surprise as memories for events of high national importance. This indicates that flashbulb memories may just be a subset of vivid memories and may be the result of a more general phenomenon. When looking at flashbulb memories and "control memories" (non-flashbulb memories) it has been observed that flashbulb memories are incidentally encoded into one's memory, whereas if one wanted to, a non-flashbulb memory can be intentionally encoded in one's memory. Both of these types of memories have vividness that accompanies the memory, but it was found that for flashbulb memories, the vividness was much higher and never decreases compared to control memories, which in fact did decrease over time. Flashbulb memory has always been classified as a type of autobiographical memory, which is memory for one's everyday life events. Emotionally neutral autobiographical events, such as a party or a barbecue, were contrasted with emotionally arousing events that were classified as flashbulb memories. Memory for the neutral autobiographical events was not as accurate as the emotionally arousing events of Princess Diana's death and Mother Teresa's death. Therefore, flashbulb memories