Principios generales

Dissociation is believed to result from extreme stress experienced during an event, such as a crime, but also from multiple incidents of trauma and unbearable violations of integrity. Shame, guilt, and grief may overwhelm

one’s coping ability, and not being able to consciously remember a trauma may serve as a protective measure, limiting conscious thoughts about an experience that are difficult to deal with or confront. It has also been hy- pothesized that degrees of dissociation exist that stand in proportion to the level of psychic pain considered tolerable by an individual. Thus, dis- sociation can range from a conscious act of denial to unconscious proc- esses leading to psychogenic forms of amnesia (e.g., Kopelman, Christen- sen, Puffett, & Stanhope, 1994; Putnam, 1997).

Although more research is needed to specify, more precisely, the condi- tions that lead to dissociation, including the mechanisms underlying the phenomenon, several case examples appear consistent with the general notion of dissociation. Adolescents who as children were involved in the production of pornography persistently denied to the police that they had actually been part of it. One of the girls could spontaneously tell the police that she remembered playing with other children, but she had no recollec- tion of adults being present, her picture being taken, or that someone re- corded her on film. The police finally showed her a photo portraying her- self as a young child in an explicit sexual act with the perpertrator. Her only response was that her hair had looked like a real mess; she refused to say anything further (Svedin & Back, 1996). By focusing on nonthreat- ening details, she may have actively inhibited memories, feelings, and thoughts associated with the abuse. Although we again stress that scien- tific research is needed, it is possible that, in cases of repeated and long- standing aversive or overwhelming experiences, the individual may de- velop dissociative behaviors that include storage of such events outside of what is considered conscious awareness. Thus, despite the range of asso- ciations to the emotional context being restricted at a conscious level, sup- pression of emotion-eliciting information intrinsically related to the stressful event may be a further necessary step to block traumatic memo- ries. Traumatic memories would then become difficult to retrieve because few links exist to other memory information. Further, because only a few links exist, intrusive emotions and thoughts may be prevented from sur- facing. Such a phenomenon is illustrated by a former victim of incest when talking about the return of memories of abuse in the following way: “This memory—it’s only been back in my consciousness for a year, so it’s very close to my feelings. Some of the other memories that came back to me almost feel as if they’re out-of-body—beyond my feelings. But this one, I just can’t defend against it” (Terr, 1994, p. 116).

Clinical observations of dissociative phenomena suggest that cognitive factors may prompt these types of reactions. For instance, although the in- dividual is unable to recount the emotional experience verbally, she may still exhibit nonverbal indications that the event is retained in memory. Such indications may be seen through emotional reactions and behavioral

reenactments that, unlike verbal memories, are beyond conscious control. A traumatized person suffering from psychogenic amnesia may, for in- stance, experience anxiety and nausea when exposed to trauma-related stimuli (cf. Christianson & Nilsson, 1989). Also, it may not be unusual for exposure to seemingly harmless details pertaining to a previously unre- callable period of life to trigger reactions that will eventually lead to con- scious recollection of the blocked memories. In one case report, an elderly man who claimed he had no idea of his personal identity or previous life history was recognized by a neighbor who had once lived next door. He was then accompanied to the apartment where somebody else now lived; still the man had no recollection of the apartment or the neighbor. A week later the man suddenly recalled that he had lost his memory following the death of his wife to whom he had been very attached (Domb & Beaman, 1991). The apartment, which presumably was associated with an emotion- ally gratifying time in the man’s life, may have triggered an affective link that bridged a gap to the episodic memory that was blocked (cf. Erdelyi & Goldberg, 1979).

Another often reported circumstance indicating the importance of cog- nitive factors (e.g., links among different memories) underlying disso- ciative tendencies concerns the kind of memory fragments usually avail- able during dissociative reactions as compared to organic amnesia. In organic amnesia, for instance as caused by head trauma, memory frag- ments tend to appear as a random assortment of details from the time of the evoking event. There are few clear temporal and causal links between the emerging memories. In contrast, there is logical and temporal order in the fragments that are remembered about a trauma. It is simply the un- pleasant information that is selectively excluded. As an example, a man lapsed into fugue state at the time of the funeral of a close relative and could only remember a few fragments. After recovery, he described these fragments as pertaining to the happiest moments of his life (Schachter, Wang, Tulving, & Freedman, 1982).

It has been hypothesized that dissociative reactions may be motivated by the inability to assimilate and accomodate stressful or traumatic expe- riences into the schemata of the individual, insofar as the individual’s schemata do not include representations of the self as being a victim of such trauma or information regarding how to interpret traumatic life events. A trauma’s disorganizing effect on cognitive processing may cause self perceptions or schemata to be altered due to an attempt to rec- oncile the experience with an individual’s self-image and outlook on life. This may result in a loss of memory for the stressful event only, or perhaps a loss of personal identity and previous life history (Horowitz & Reidbord, 1992). Such loss is commonly referred to as psychogenic amnesia and constitutes the extreme form of a dissociative reaction because full

amnesia enables an individual to block out entirely threatening or unbear- able experiences. In the latter case, it is no longer a matter of deliberately applying a strategy to render certain memories less accessible to con- sciousness. It is instead an extreme defense reaction that is automatically activated by the immense and cumbersome emotional stress and that tem- porarily hampers mechanisms for retrieval of all information related to one’s self history.

CONTEXT-DEPENDENT RETRIEVAL CUES, MEMORY