Elsevier

International Journal of Law and Psychiatry

Volume 32, Issue 5, September–October 2009, Pages 329-334
International Journal of Law and Psychiatry

A comparison of memory for homicide, non-homicidal violence, and positive life experiences

https://doi.org/10.1016/j.ijlp.2009.06.008Get rights and content

Abstract

Defendants commonly claim amnesia for their criminal actions especially in cases involving extreme violence. While some claims are malingered or result from physiological factors, other cases may represent genuine partial or complete amnesia resulting from the psychological distress and/or extreme emotion associated with the perpetration of the crime. Fifty Canadian homicide offenders described their memories of their homicide, a non-homicide violent offense, and their most positive adulthood life experience. Self-reported and objective measures of memories for these events revealed that homicides were recalled with the greatest level of detail and sensory information. Although dissociative tendencies were associated with a self-reported memory loss, objective measures of memory quality did not reflect this perceived impairment, suggesting a failure of meta-memory. Recollections of positive life events were superior to those of non-homicidal violence, possibly due to greater impact and meaning attached to such experiences. Findings suggest that memory for homicide typically is enhanced by the powerful emotion associated with its perpetration.

Section snippets

Non-homicidal violence, and positive life experiences

Defendants commonly claim partial or complete amnesia for their criminal actions (e.g., Gudjonsson & MacKeith, 1983; Kopelman, 1995, Porter et al., 2001, Roesch and Golding, 1986, Schacter, 1986), typically in cases involving violent crime. In some cases, such reported memory impairment is associated with mental illness (e.g., Bourget, Labelle, Gagne, & Tessier, 2004); a study of 118 homicide offenders found that psychotic disorders were present in 24% of the offenders who claimed amnesia (

The present study

The purpose of the current investigation was to examine perpetrators' memory for their homicide offence relative to another violent offence and a positive life experience. One of the limitations of many previous studies of memory for crime is that there has been no “control group” of memories among the same participants to allow a more refined consideration of the influence of powerful emotion on memory and to control for individual differences. The current investigation is, to our knowledge,

Participants

Fifty participants were recruited from the population of approximately 150 federal male offenders currently incarcerated in Atlantic Canada for homicide (manslaughter, first or second-degree murder). Participants were recruited from Springhill Institution in Nova Scotia (n = 18), and Dorchester Penitentiary (n = 21) and Atlantic Institution (n = 11) in New Brunswick. The mean age of participants was 39.5 years (SD = 9.2, range 22–55 years). Participation in the study was completely voluntary and no

MAP reliability check

An inter-rater reliability check was conducted on the amount of detail component of the Memory Assessment Procedure (MAP, Porter et al., 1999) to ensure that details were being coded consistently between coders across the three memory types. Correlations indicated that detail coding was reliable between raters for homicide, non-homicide, and positive experiences, with correlations ranging from .80 to .92 (all p's < .001).

Self-reported & qualitative memory characteristics1

Self-reported memory characteristics were assessed using the EMS. Offenders

Discussion

While some violent offenders are motivated to feign memory loss to avoid self-incrimination and/or to suggest a lack of criminal intent (Merckelbach & Christianson, 2007), genuine impairments of memory may occur due to a variety of psychological factors, including dissociation and state-dependent effects, as well as potentially from physiological factors. When attempting to discriminate genuine and malingered amnesia in forensic contexts, professionals must evaluate the self-reported amnesia

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