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Examining the Impact of Proximate Culpability Mitigation in Capital Punishment Sentencing Recommendations: The Influence of Mental Health Mitigators


In spite of the ruling in Atkins v. Virginia (2002), concerns remain that individuals with mental illness and reduced capacity are eligible for the death penalty. When mental illness or reduced capacity is not enough to preclude death-eligibility, these factors are often discussed at the sentencing phase as mitigators. Mitigation remains an under-researched avenue in the sentencing literature, particularly when it comes to the influence of specific types of mitigation. The present study contributes to knowledge on mental health mitigation by examining five mitigators relevant to the mental health and capacity of defendants. Using data from 834 capital sentences in North Carolina, the influence of these proximate culpability mitigators on jury sentence recommendations is examined. Results indicate that acceptance of certain mental health mitigators reduces the probability of death, but acceptance of others is not significantly related to death recommendations. These findings and their implications are discussed.

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  1. 1.

    The primary exception being analyses associated with the Capital Jury Project.

  2. 2.

    The majority of states use and have used juries to make the sentencing recommendation. Some states allow for a jury or three judge panel to make this determination; however, Ring v. Arizona (2002) limited this practice, requiring that juries decide the presence of an aggravating factor (s), not a judge. A handful of states still rely on judges to determine the final sentence, though under fairly narrow circumstances (for details, see Bjerregaard, Smith, & Fogel, 2009).

  3. 3.

    There are seven common statutory mitigating factors: 1) the defendant has no significant criminal history, 2) the defendant was suffering from mental or emotional disturbance, 3) the victim was somehow a participant in the situation leading to the murder or gave consent, 4) the defendant was acting under duress, 5) imperfect insanity and/or intoxication, i.e. not enough to qualify as an excuse or successful defense, 6) the age of the defendant at the time of the crime, and 7) the defendant was a more minor participant in the crime. An additional statutory mitigator, defendant belief in moral justification or extenuation, has not been as widely adopted (Acker & Lanier, 1994). The above statutory mitigating factors are not an inclusive list, nor do all of these appear in every state, but they do provide the basis for statutory mitigation in the United States.

  4. 4.

    While not a mock juror study per se Barnett et al. (2004) and White (1987) derived their pool of mock jurors from a sample of college students. So, while the lack of death-eligibility may influence the findings, the demographics of the sample are similar to those of the two previous mock jury studies and thus is included in this discussion.

  5. 5.

    This critique is not meant to suggest that examining the influence of mitigators singularly was a methodological error. Obviously, this is a useful method for determining jurors and potential jurors responses to specific mitigating circumstances. However, in real capital trials jurors are likely to be presented with multiple mitigating (and aggravating) circumstances and thus it is important to consider the influence of mitigators in concert with additional factors.

  6. 6.

    For an investigation of the potential influence of mitigation pre- and post-McKoy see Kremling et al. (2007).

  7. 7.

    Fifty-one cases were removed from analysis because the jury did not find an aggravating factor, and therefore mitigators were not considered. Forty-eight cases were eliminated because the Issues and Recommendations as to Punishment forms (which identify acceptance and rejection of submitted aggravators and mitigators) could not be located in county files, or were not completed by the jury for various reasons. The remaining two cases were missing information on one of the mitigators of interest. The source of this missing information was that the mitigator was submitted but the jury did not indicate whether they accepted it on the Issues and Recommendations as to Punishment form. All 101 of these “missing” cases resulted in life sentences, resulting in a proportional overrepresentation of death sentences in the working sample.

  8. 8.

    In some states the age mitigator is considered chronological. In North Carolina, however, legal opinions have noted that age may be submitted in order to signify mental or emotional age, not just chronological age; e.g., "We have held that chronological age is not the determinative factor with regard to this [age] mitigating circumstance. State v. Oliver, 309 N.C. 326, 307 S.E.2d 304 (1983). The defendant's immaturity, youthfulness, or lack of emotional or intellectual development at the time of the crime must also be considered" (State v. Bowie, 1995).

  9. 9.

    Multicollinearity did not appear to be a concern in these analyses. Variance Inflation Factors (VIFs) were all under 2.5 in both models, the highest being 2.223.


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Correspondence to Lane Kirkland Gillespie.

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Gillespie, L.K., Smith, M.D., Bjerregaard, B. et al. Examining the Impact of Proximate Culpability Mitigation in Capital Punishment Sentencing Recommendations: The Influence of Mental Health Mitigators. Am J Crim Just 39, 698–715 (2014).

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  • Capital sentencing
  • Mitigation
  • Death penalty
  • Mental health