Interidentity Memory Transfer in Interidentity Memory Transfer in Dissociative Identity Disorder Dissociative Identity Disorder

Megan WhitmoreMegan Whitmore

Marissa LongMarissa Long

Jordan McNeelyJordan McNeely

Dissociative Identity DisorderDissociative Identity Disorder -A mental process which produces a lack of connection in a person’s -A mental process which produces a lack of connection in a person’s

thoughts, memories, feelings, actions, or sense of identity.thoughts, memories, feelings, actions, or sense of identity. -Characterized by the presence of two or more split identities or personality -Characterized by the presence of two or more split identities or personality

states that continually have power over a person’s behavior (American states that continually have power over a person’s behavior (American Psychiatric Association, 2000).Psychiatric Association, 2000).

The identities are separable person-like states with idiosyncratic memories, The identities are separable person-like states with idiosyncratic memories, personal history, and personality traits (4th ed., text rev.; DSM-IV-TR; personal history, and personality traits (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000) and include the inability to recall American Psychiatric Association, 2000) and include the inability to recall key personal information that is too far reaching to be explained as key personal information that is too far reaching to be explained as forgetfulness, termed forgetfulness, termed interidentity amnesiainteridentity amnesia

-Considered the most severe dissociative disorder-Considered the most severe dissociative disorder -Usually thought to stem from prior trauma-Usually thought to stem from prior trauma -Thought to be a coping mechanism, where the person literally dissociates -Thought to be a coping mechanism, where the person literally dissociates

himself from a situation or experience that’s too violent, traumatic, or painful himself from a situation or experience that’s too violent, traumatic, or painful to assimilate with his conscious selfto assimilate with his conscious self

-The highly distinct memory variations fluctuate with the person’s split -The highly distinct memory variations fluctuate with the person’s split personalitiespersonalities

The StudyThe Study As stated by the researchers of this study, identities are not As stated by the researchers of this study, identities are not

conceptualized as truly distinct identities with clear-cut disruptions in conceptualized as truly distinct identities with clear-cut disruptions in consciousness and memory, but rather as a metaphor used by the consciousness and memory, but rather as a metaphor used by the individual for explaining subjective experiences. individual for explaining subjective experiences.

According to this hypothesis, amnesia between identities should According to this hypothesis, amnesia between identities should unfold via normal mnemonic processes such as self-distraction or unfold via normal mnemonic processes such as self-distraction or strategies aimed at prohibiting recall, and this study attempted to strategies aimed at prohibiting recall, and this study attempted to validate that hypothesis.validate that hypothesis.

the cross-modal manipulation in this study ensured that findings the cross-modal manipulation in this study ensured that findings of memory transfer would be attributed to explicit memory rather of memory transfer would be attributed to explicit memory rather than implicit effects.than implicit effects.

it examined the extent of explicit memory transfer between it examined the extent of explicit memory transfer between identities in an exclusion paradigm whereby amnesia is difficult to identities in an exclusion paradigm whereby amnesia is difficult to simulate. In addition, a cross-modal manipulation was employed to simulate. In addition, a cross-modal manipulation was employed to mitigate any possible implicit effects.mitigate any possible implicit effects.

MethodMethod

ParticipantsParticipants• Participants had to meet DSM-IV diagnostic criteria for DID, have Participants had to meet DSM-IV diagnostic criteria for DID, have

interidentity amnesia, and have the ability to switch between interidentity amnesia, and have the ability to switch between specified identities at willspecified identities at will

• Originally 8 DID participants but only 7 completed the study, of Originally 8 DID participants but only 7 completed the study, of these 6 were femalethese 6 were female

• 34 control participants, 4-6 matched to each DID participant based 34 control participants, 4-6 matched to each DID participant based on gender, age, and educationon gender, age, and education

Method Cont.Method Cont.Procedure for DID ParticipantsProcedure for DID Participants

• First sessionFirst session• DID patients were given two separate interviews to validate their DID patients were given two separate interviews to validate their

conditioncondition• They also completed a vocabulary testThey also completed a vocabulary test

• Second sessionSecond session• The researchers presented Identity A with list A audibly via computer The researchers presented Identity A with list A audibly via computer

and then reviewed the words by using them in stories and then and then reviewed the words by using them in stories and then having them listed againhaving them listed again

• After researchers confirmed the switch to Identity B, they confirmed After researchers confirmed the switch to Identity B, they confirmed the supposed interidentity amnesia. the supposed interidentity amnesia.

• Then Identity B was presented with list B in the same fashion as list AThen Identity B was presented with list B in the same fashion as list A• Identity B was given a forced choice exam regarding the memory Identity B was given a forced choice exam regarding the memory

stories thatstories that• had been told to Identity A, no one remembered anything significanthad been told to Identity A, no one remembered anything significant• Identity B was then visually presented with words from list A list B and Identity B was then visually presented with words from list A list B and

a third list termed distracter words, identity was continually checked a third list termed distracter words, identity was continually checked during this time to guard against rapid switching during this time to guard against rapid switching

Method Cont.Method Cont.

Procedure for ControlProcedure for ControlThe controls were educated on DID and The controls were educated on DID and

then asked to simulate an intricate then asked to simulate an intricate alternative personalityalternative personality

Afterwards they completed the second Afterwards they completed the second session tests that the DID participants had session tests that the DID participants had completed completed

ResultsResults

Both the control and DID participants were Both the control and DID participants were significantly more likely to say “yes” to list significantly more likely to say “yes” to list A words than distracter words when A words than distracter words when attempting to identify list B wordsattempting to identify list B words

The DID participants did not perform The DID participants did not perform significantly different form the control significantly different form the control participants in aspect participants in aspect

DiscussionDiscussion

Both the control group and the DID participants claimed to Both the control group and the DID participants claimed to have no subjective memory for previous events after switching have no subjective memory for previous events after switching to their amnesic identityto their amnesic identity

However, both groups showed signs of memory transfer on the However, both groups showed signs of memory transfer on the cross-modal exclusion taskcross-modal exclusion task

If interidentity amnesia was present among DID patients, the If interidentity amnesia was present among DID patients, the results should have produced equal ability to reject both List A results should have produced equal ability to reject both List A and distractor words. However, they were able to reject and distractor words. However, they were able to reject distractor words but not List A words.distractor words but not List A words.

Amnesic barriers between identities may not be as Amnesic barriers between identities may not be as impermeable as perceived by patients.impermeable as perceived by patients.

Discussion Cont.Discussion Cont.

The findings do not address the role of trauma in people with The findings do not address the role of trauma in people with DID and cannot say whether or not trauma can produce DIDDID and cannot say whether or not trauma can produce DID

Neuropsychological Tests- all patients showed the same Neuropsychological Tests- all patients showed the same patterns. patterns.

The 3 patients that had the lowest Dissociative Experience The 3 patients that had the lowest Dissociative Experience Scale had been diagnosed with DID for the longest length of Scale had been diagnosed with DID for the longest length of time. This shows possibility that living with DID over time time. This shows possibility that living with DID over time resulted in more adjustment and acceptance of DID as part of resulted in more adjustment and acceptance of DID as part of their daily life.their daily life.

ConclusionConclusion

The results may not apply to all DID participants; a larger The results may not apply to all DID participants; a larger sample would increase the generalizability of the resultssample would increase the generalizability of the results

The study only tested one possible pairing of identities within The study only tested one possible pairing of identities within the patients. Which leaves the possibility that other identities the patients. Which leaves the possibility that other identities would have demonstrated better compartmentalization.would have demonstrated better compartmentalization.

Posttraumatic perspective might predict that amnesic barriers Posttraumatic perspective might predict that amnesic barriers would be more distinct in identities responsible for dealing would be more distinct in identities responsible for dealing with traumatic memories. Traumatic memories have been with traumatic memories. Traumatic memories have been found between trauma-related identities. This may suggest that found between trauma-related identities. This may suggest that these identities may have different levels of memory these identities may have different levels of memory compartmentalization. compartmentalization.

Conclusion Cont.Conclusion Cont.

Overall, there were no significant differences in patterns of Overall, there were no significant differences in patterns of exclusion performance between DID group and the control exclusion performance between DID group and the control group. group.

Also, implicit tests are not necessary to demonstrate Also, implicit tests are not necessary to demonstrate interidentity memory transfer. However, explicit memory tests interidentity memory transfer. However, explicit memory tests that are designed to be objective and difficult to fake can that are designed to be objective and difficult to fake can reveal memory transfer between subjectively amnesic reveal memory transfer between subjectively amnesic identities. identities.