ABSTRACT
There are many questions about interpersonality amnesia that are as yet unanswered. Perhaps the most salient one, and the one that most of this chapter addresses, is this: Is knowledge that is acquired by one personality completely compartmentalized and unavailable to another personality, or can it be shown that acquired knowledge can exert an inHuence across personalities? A second general issue involves the extent of interpersonality amnesia. Are all memories effectively compartmentalized, or only some? If only some, which ones, or which types? Alternate personalities typically share some abilities that require memory, such as reading and calculation, and they typically share general world knowledge, such as the names of cities and the customs of daily life. Is this knowledge represented separately and redundantly for each personality, or does it have a single representation in memory, but one that all personalities can access? In either case, why is this knowledge not functionally compartmentalized? One possibility is that it is available across personalities because it is emotionally neutral; another is that it does not involv(: memories of particular episodes in the past; yet another hypothesis is that this knowledge is not compartmentalized because it was acquired before the dissociation of personalities. This last possibility raises another issue: Is the amnesia observed in MPD only
anterograde amnesia, affecting information learned after the dissociation, or does it also have a retrograde component, affecting memory for information learned before the dissociation? The idea that dissociation occurs in order to provide protection against having to remember traumatic events assumes that there is a retrograde component. Mary Reynolds, the first case of MPD to be described in detail (S.L. Mitchell, 1816; S.W. Mitchell, 1889) apparently was amnesic for all knowledge acquired prior to dissociation, including the skills of reading, calculation, and writing, but it is more typical that not all knowledge acquired before the dissociation is compartmentalized.
