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Jodi Arias Trial: The Importance of Forensic Psychology Guidelines

Jodi Arias Trial: The Importance of Forensic Psychology GuidelinesI have served as a clinical and forensic neuropsychologist expert witness for over twenty years. It is of utmost importance that an even playing field be created in adversarial proceedings.

What is conducive to this is use of forensic guidelines as standards by all experts involved in a case.

The Jodi Arias trial depicts apparent omissions of important standards that could influence outcome of assessment. There was a lack of collateral interviews, which the Reference Manual for Scientific Evidence (RMSE) addresses.

In addition, there were other omissions that I believe are important to the outcome of the Jodi Arias trial.

In addition to reviewing records, interviewing third-party informants can provide important perspectives on the person being evaluated. Family members and friends can relate behavior and patterns indicative of symptoms of a mental disorder or functional impairment. Collateral parties can help to confirm or disconfirm the evaluator’s impressions.

This did not appear to have been done in Arias’s trial. An evaluation of only the defendant is weighted toward the defendant’s self-report. This leaves an evaluation without information from third parties who can provide various perspectives on a defendant.

It is difficult to understand how Arias was considered a victim of abuse when there did not appear to be any police reports or documented instances of domestic violence. Additionally, there did not appear to be any consideration of her abusive behavior. (For example, she was alleged to have slashed tires on the victim’s car and peeked in the window of the victim’s house.)

The testimony from one expert related to the fact that Arias suffered from post-traumatic stress disorder (PTSD). It is important to recognize that PTSD criteria did not appear to be established by any corroborating evidence. It appears that the experts focused on “PTSD” and “lack of memory” issues and not neuropsychological and clinical assessments.

Neuropsychological deficits often are seen in extreme violence. Clinical assessment can reveal presence of psychopathic traits. Moreover, it was presented that Arias had taken a video of the victim prior to the alleged murder. It is difficult to understand how she lacked “memory” of the homicide when she was capable of filming the victim shortly beforehand.

Furthermore, the prosecutor asserted that Arias had purchased cans of gas at a remote distance from the crime scene so as not to use credit cards near the scene of the allegations. These would appear to be facts which support premeditation rather than “not remembering.” The latter is difficult to understand when evidence indicated that the victim was trying to escape while being allegedly stabbed. All of these facts appear to support premeditated behavior.

It is important to integrate the physical findings of the crime scene with the psychological profile of the defendant. I presented a seminar at the University of California-Irvine on Psychological Profiling and Crime Scene Analysis, and also, in an evaluation of a capital case. This analysis is particularly crucial in cases such as this because a subjective interview with the defendant is verified against physical characteristics of crime scenes. This assists the jury and the judge in understanding and integrating analysis of the crime scene with subjective interviews and objective psychological test findings.

None of the experts appeared to have evaluated or considered crime scene evidence with their findings.

Mechanic (2002) speaks of stalking from attachment perspectives, which can be conceptualized as seeking to reestablish connection with partners to secure a base in the face of perceived separation. A defense witness stipulated to Arias peeking in the window of the victim’s house while he kissed another female. She stated that this was not stalking. This is difficult to understand given the research of Mechanic (2002), which defines stalking as to annoy or harass, with fear being a main component.

It is incumbent upon forensic evaluators to be objective experts, avoiding dual roles which could create the appearance of bias. However, in the Arias case, two separate experts apparently gave her a book, one of which reportedly apologized for looking at her diary. It is difficult to understand how this occurred when contraband is not allowed in correctional facilities. In any event, it impairs objectivity in expert evaluators. The RMSE was formulated to provide the tools for judges to manage cases involving complex scientific and technical evidence. The manual also addresses what to do when deception is suspected.

Guidelines are important standards for contributing to the reliability and validity of data from forensic examinations. These are standards to be striven for by all practitioners in the pursuit of good science and practice. Although there were significant omissions in the Arias trial, the jury carried out its duty, and carried it out well by focusing on the facts, evidence supporting the facts, and rendered a verdict of guilty of first-degree murder.


American Psychological Association. (2012). Specialty Guidelines for Forensic Psychology. Washington, D.C.: APA Press.

Applebaum, P. S. (2011). Reference Manual on Scientific Evidence: Third Edition. Washington, D.C.: The National Academies Press.

Davis, K. E., Frieze, I. H., & Mairuo, R. D. (2002). Stalking Perspectives on Victims and Perpetrators. New York: Springer Publishing.

Heilbrun, K. (2001). Principles of Forensic Mental Health Assessment. Kluwer.

Mechanic, M. B., Weaver, T. L., & Resick, P. A. (2000). Intimate partner violence and stalking behavior: Exploration of patterns and correlates in a sample of acutely battered women. Violence Vict, 15(1), 55:72.

Mechanic, M. (2002). Stalking victimization: Clinical implications for assessment and intervention. Stalking: Perspectives on Victims and Perpetrators, 31-61.

Specialty Guidelines for Forensic Psychology. (n.d.). Retrieved from

Jodi Arias Trial: The Importance of Forensic Psychology Guidelines

Michael J. Perrotti, PhD

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APA Reference
Perrotti, M. (2018). Jodi Arias Trial: The Importance of Forensic Psychology Guidelines. Psych Central. Retrieved on September 27, 2020, from
Scientifically Reviewed
Last updated: 8 Jul 2018 (Originally: 24 Jul 2013)
Last reviewed: By a member of our scientific advisory board on 8 Jul 2018
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