Rafaële J.C. Huntjens, Albert Postma, Liesbeth Woertman, Onno van der Hart and Madelon L. Peters (2005)
Procedural memory in dissociative identity disorder: When can inter-identity amnesia be truly established?
Consciousness and Cognition Volume 14, Issue 2 , June 2005, Pages 377-389
doi:10.1016/j.concog.2004.10.001

Abstract: In a serial reaction time task, procedural memory was examined in Dissociative Identity Disorder (DID). Thirty-one DID patients were tested for inter-identity transfer of procedural learning and their memory performance was compared with 25 normal controls and 25 controls instructed to simulate DID. Results of patients seemed to indicate a pattern of inter-identity amnesia. Simulators, however, were able to mimic a pattern of inter-identity amnesia, rendering the results of patients impossible to interpret as either a pattern of amnesia or a pattern of simulation. It is argued that studies not including DID-simulators or simulation-free memory tasks, should not be taken as evidence for (or against) amnesia in DID.

Rafaële J.C. Huntjens, Madelon L. Peters, Albert Postma, Liesbeth Woertman, Marieke Effting and Onno van der Hart (2005)
Transfer of newly acquired stimulus valence between identities in dissociative identity disorder (DID)
Behaviour Research and Therapy Volume 43, Issue 2 , February 2005, 243-255
doi:10.1016/j.brat.2004.01.007

Abstract: Patients with Dissociative Identity Disorder (DID) frequently report episodes of interidentity amnesia, that is amnesia for events experienced by other identities. The goal of the present experiment was to test the implicit transfer of trauma-related information between identities in DID. We hypothesized that whereas declarative information may transfer from one identity to another, the emotional connotation of the memory may be dissociated, especially in the case of negative, trauma-related emotional valence. An evaluative conditioning procedure was combined with an affective priming procedure, both performed by different identities. In the evaluative conditioning procedure, previously neutral stimuli come to refer to a negative or positive connotation. The affective priming procedure was used to test the transfer of this acquired valence to an identity reporting interidentity amnesia. Results indicated activation of stimulus valence in the affective priming task, that is transfer of emotional material between identities.