Human Memory 207, Do Flashbulb memories differ from other forms of memory?" Our past is preserved in a variety of memories of very different nature" (Salam an, 1970) There are many proposed divisions and sub-divisions of human memory, such as working memory, procedural memory, semantic memory or episodic memory. Many of the systems seem to overlap, with each having varying functions related to the maintenance of what is essentially human life. For example, episodic and autobiographical memory fundamentally share the same functions. One of the many functions is what Tul ving (1983) called "Mental time travel", the ability to experience past event. Autobiographical memories are thought to be structured at different levels of temporal and spatial specificity that together are used as reference for the construction of "self." This mental time travel can take place through different hierarchic levels of autobiographical organisation.

The hierarchy level can be as general as "university" or as specific as remembering the topic of conversation with a certain person on a certain day (Cohen, 1998). Autobiographical memories are therefore seen as being auto noetic in that they carry information about the context in which they were experienced. One example of an extreme form of contextual specific memory is the death of Princess Diana. Many people especially the media ask a common question such as "what were you doing when you heard the news." Many people claim to be able to remember such major moments with unusual clarity and vividness, as if the events were etched on their minds throughout their lives. The question is whether these "flashbulb memories" are functionally different to all other types of memory such as autobiographical memory. Brown & Kulik (1977), introduced the term flashbulb memory to describe memories that are preserved in an almost indiscriminate way.

They postulated that these flashbulb memories were indeed different from ordinary memories, with some defining characteristics. Although these memories are thought to be photographic in their clarity and detail, they do not preserve all features of an event. Conversely Brown & Kulik proposed that idiosyncratic event details are remembered. These details help form what has been described as a "live" memory in that the "reception field" is remembered including 'where', 'when' and 'who with' factors of an event. Brown & Kulik (1977) studied memories for important events such as the death of John F Kennedy. They found that irrelevant details were often recalled and it appeared that they had retained "a brief moment of time associated with an emotional event" (Smyth et al, 1994).

Brown & Kulik suggested that flashbulb memories are formed by the activity of an ancient brain mechanism evolved to capture emotional and cognitive information relevant to the survival of an individual or group. To summarise, flashbulb memories FMs are thought to be an unique survival mechanism distinct from other form of memory in their clarity, longevity and attention to idiosyncratic detail. These characteristics of flashbulb memories can be mapped onto issues concerning memory. As with many memory systems, the argument over the distinctiveness of flashbulb memories involves encoding, storage and retrieval. These issues relate to many issues within Flashbulb memory such as their formation, accuracy, consistency and longevity. It appears that these processes are interrelated with each process being dependent on another.

In terms of FM formation, Brown & Kulik thought that the clarity and detail of FMs is correlated with the emotion, surprise and personal consequentiality of the event. They also thought that surprise initiates FM formation, while personal consequentiality determines the elaborateness of the resulting FM. As support for this they found that more blacks had FMs associated with the death of Martin Luther King compared to whites. Apparently this was due to an increased emotional personal consequentiality felt their part of society.

Therefore self referring prior knowledge of surprising important events is thought to support privileged encoding of FMs compared to other mundane memories. In support for this Livingstone (1967) proposed that when an event passes a certain biological criterion, the limbic system discharges into the reticular system, which further discharges throughout the cortical hemispheres. This firing above a certain level has been termed the "now print" mechanism. This system can be seen as being rather like the flash going off on a camera. However this view is criticised on the grounds that this "biological level" is not specifically identified. In a further criticism Neisser (1982 c) has claimed that FMs are not specially encoded and therefore not unique.

Neisser proposed that FMs were Simply ordinary memories made clearer and longer lasting by frequent rehearsal after the event. This argument seems quite logical, as particularly in this global age the media and society frequently replay and retell events of extreme public attention or emotion. Flashbulb memories could therefore be seen as memories that have be actively reconstructed to such an extent that they can be clearly replayed in our minds. Flashbulb memories are seen by Neisser not as a special evolutionary mechanism, but as a method of promoting the integration of an individual within a society. In this reconstruction, personal consequentiality is applied after an event once is importance is measured within society. This also questions the validity and accuracy of "flashbulb memories" in that they are memories actively reconstructed and transformed over time.

Neisser & Harsh (1992) measured flashbulb memories of the shuttle challenger explosion. They found that after one day 9 subjects claimed to have learned of the event from television, however 34 months later this figure had risen to 19. As a further nail in the coffin for Brown and Kulik's flashbulb memory hypothesis Christianson & Loftus (1987) found that high emotion served to narrow attention to focus to the central aspects of an event a the expense of peripheral details. This would seem to indicate that the idiosyncratic details associated with flashbulb memories are more reconstructive, as the periphery surrounding an event is filled in on rehearsal. At this point it may appear that flashbulb memories are little more than a cultural phenomenon involving an enhancement of ordinary memories and therefore not different from them.

McCloskey et al (1988) have pointed out that ordinary memories can be accurate and long lasting due to frequent rehearsal. FMs are therefore may be ordinary memories retained to some unusually high standard of clarity. However there has been a considerable backlash in support of uniqueness of flashbulb memories. Various researchers have pointed to the fact that personal consequentiality was not measured within either the challenger or other such studies. As already demonstrated by Brown and Kulik (1977), emotional consequentiality is a dominant factor in the formation of FMs as seen in their comparison of FMs for Malcom X between blacks and whites. In a similar study, Conway (1994) measured FMs of the resignation of Margaret Thatcher.

Conway took measures immediately and around 9 months. Conway found that over 86% of British subjects had complete and accurate memories fitting the description of FMs. Conversely only 29% of non-British subject shad 'FM' memories. In a comparison of three studies of important news events such as the resignation of including his own and the San Francisco earthquake (Neisser, Wino grad, and Weldon, 1991), Conway (1995) concluded that FMs may be mediated by importance and / or emotion, but not rehearsal.

Conway used these studies as support for the idea that encoding is special for flashbulb memories and that they are not purely the production of elaborate rehearsal. Although Conway found In terms of accuracy of flashbulb memories. Rehearsal is thought to serve different functions for different memories. Smyth et al (1994) noted that some memories successfully remain with us accurately for many years.

They furthered that these extended memories could be distinguished between memories that have used over a period of time and emotionally charged flashbulb memories. Conway (1995) suggests that rehearsal may serve to prevent these ordinary memories from decaying while rehearsal within flashbulb memories acts to elaborate. It may be that ordinary memories require preventative rehearsal due to their instability. Conway (1995) believed that most autobiographical memories are unstable and dynamic requiring effort full maintenance. Conway & Anderson (1993) believe that ordinary memories are constructed from different types of autobiographical knowledge and not directly accessed as in a "memory unit." Flashbulb memories however are believed to represent tightly organised and dense autobiographical knowledge. FMs are therefore thought to be different to ordinary memories in their specificity of knowledge and organisation within the brain.

have suggested that there are In terms of accuracy, Conway has pointed to the fact that Brown and Kulik never claimed that FMs were perfect. Examples of personal FMs, those experienced solely by individuals support Conway's arguments of the speciality of encoding being independent of rehearsal. Christianson and Nilson (1989) site the unfortunate case of a rape victim who developed amnesia, supposedly motivated as a removing the event from memory. However the victim was jogging a year later when a sudden flashbulb memory or flashback was experienced. This was cued by the victim noticing a similar brick pattern to that seen during the attack.

According to Conway and Brown & Kulik, the differences between ordinary memory and FMs would be self evident in this sort of incident. Due to their dense organisation, FMs can be compared to a tightly wound spring in that they are hollis tc. The issue of flashbulb memories being indelible It appears therefore that FMs may as first thought have a unique encoding mechanism that is independent of rehearsal. Pileser et al (1988) - emotion In conclusion, the distinction between FMs and ordinary memories is in clear in places unfortunately this difference is not universal. There seems to be a fine line between vivid autobiographical memories and flashbulb memories.

There seems to be many factors influencing flashbulb memory formation, however these have been broken down primarily to personal consequentiality, importance of an event and emotion. Surprise is thought to be a significant factor that combines with the other three to promote the ideal conditions for flashbulb memory formation. Conway (1994) has concluded that during events importance interacts with emotion to form FMs. Conway's evaluation does not describe how vivid autobiographical memories may represent different systems to flashbulb memories. The personal problem I have concerning the distinctiveness of FMs was encountered recently. Whilst typing an essay, I experienced an extremely vivid flashback to a time I had stopped in a service station in Australia.

I distinctly remember buying a green ice lolly, and what the view was like out of the window. This event had little impact on my life and I remember being completely relaxed at the time. I had been travelling for a while and these stops were frequent enough to not be a "first time experience" and at the time could be considered mundane. On reading the literature I struggled to find concrete information to ascertain if this experience was a FM or just a very vivid autobiographical memory. The experience had not been rehearsed, yet was brought back spontaneously with incredible clarity more than two years on. Supporters of FMs would argue that this memory In terms of long term potentiation this memory may LTP put in buffer zone activated by levels of arousal or attention that were high for the entire trip.

Once back in England, the whole of that experience may have been related to personal importance and Current life plans (Conway, 1995) and therefore what was not seen as important at the time may have become so a few months later. Similarly my memories of university so far seem quite vague, however it may that once my life plans change in the future, some of these memories may be afforded flashbulb quality. Perhaps many of these memories are of flashbulb quality, but are not remembered at the moment as such as they have little consequence in an environment that is constant. In my opinion there is a sliding continuum in terms of flashbulb memories and other autobiographical memories. As mentioned, autobiographical memories are thought to be arranged in a hierarchic structure that involves levels of general and minute. In my opinion, FMs represent the formation of extreme memories that require little thought to remember.

In this way FMs may be different to ordinary memories, in that they are simply higher on the scale of specificity. My argument therefore is that yes flashbulb memories are different from ordinary mundane autobiographical memory. As vivid memories are also distinct from mundane memories, FMs in my opinion are not unique in their formation, longevity and clarity. Conway argued that the distinction of FMs and autobiographical memory is the reconstructive quality of ordinary memories. However studies of patients within intensive care units (Jones, Griffiths & Humphries, 2000) have shown that in the understandable unpleasant emotions coupled with drugs enhances memory for internal events such as hypnogogic hallucinations. Attention shifts during these hypnogogic images from the external to the internal.

Patients show poor recall for their external environment, but vivid memories for the hallucinations and nightmares. Although the authors use Conway's suggested four variable interaction to explain the events in terms of emotion and personal consequentiality, the fact that these vivid memories were constructed and not in fact viewed independently may weaken the difference between FMs and other autobiographical memories. It seems that FMs have been applied to so many extreme memory phenomenon that they are a class of their own. Mauricio & German (1999) have claimed that to see flashbulb memories as being unique and without parallel in psychology is wrong. They argue that psychologists should consider flashbulb memories as being members of a "broad family of experiences that include drug flashbacks, , , post traumatic memories, and the vivid and haunting memories experienced by subjects with some forms of mental disorder." As the longevity and accuracy of memories involved with post traumatic stress disorder has been questioned (Badd eley, 1997) In conclusion there is considerable evidence that humans do have memories that are extremely vivid, clear and long lasting. However these FMs themselves.