Effects of Mental Health and Neuroscience Evidence on Juror Perceptions of a Criminal Defendant: the Moderating Role of Political Orientation

Abstract

Several recent studies have examined the effects of mental health and neuroscientific evidence on attitudes toward criminal defendants, suggesting that these factors may influence juror decision-making in meaningful ways. Few studies to date have manipulated both of these variables while also considering theoretically important individual difference variables (e.g., political orientation). Using a criminal case simulation, this study manipulated the presence of evidence concerning mental disorders (psychopathy and schizophrenia) and increasing levels of neuroscientific detail regarding a defendant's brain injury, and examined verdicts and sentencing recommendations in over 400 persons attending jury duty. Main effects were detected for mental health testimony and political orientation, although interactions were noted as well. More negative reactions to defendants labeled as psychopaths were relatively consistent, whereas participants who identified as liberal generally were less punitive towards a defendant identified as schizophrenic than were more conservative jurors. Consistent with other recent research, juror perceptions of the defendant's level of psychopathic traits (independent of the effects of the experimental manipulations) predicted guilty verdicts and longer sentencing recommendations. Copyright © 2016 John Wiley & Sons, Ltd.

Dangerous, depraved, and death‐worthy: A meta‐analysis of the correlates of perceived psychopathy in jury simulation studies

“…Relatively few studies have investigated this question, but mock juror ratings of other forms of psychopathology (e.g., borderline personality traits and psychosis) do not appear to significantly predict the types of legal outcomes investigated in this meta‐analysis. These other psychological characterizations have been found to be relatively mitigating or entirely unrelated to punitive decision‐making, including perceptions of defendant guilt, death verdicts, and sentence length (Cox et al, ; Edens et al, ; Gurley & Marcus, ; Mowle et al, ). It has been argued by some (e.g., Frick & Nigg, ) that psychopathic traits are not especially more stigmatizing than other types of mental health information, but the results of this meta‐analysis in combination with findings from the individual studies noted above would seem to contradict such a claim.…”

“…Instead of, or in addition to, summary variables based on individual item‐level ratings, four of the studies relied on singular Likert‐type ratings to assess psychopathy (e.g., Mowle, Edens, Clark, & Sörman, ), with participants instructed to globally rate how psychopathic they perceived the defendant to be after reviewing the case vignette and stimulus materials. These Likert‐type ratings included anchor points ranging from not at all psychopathic to extremely psychopathic .…”

Mock Juror Perceptions of Credibility and Culpability in an Autistic Defendant

“…Participants were also asked to what extent they believed the defendant was to blame for the incident (7-point Likert scale), whether they felt he should receive a guilty or not guilty verdict (guilty, not guilty) and, if they reported that he should be found guilty, how harshly he should be sentenced (7-point Likert scale). These questions were adapted for the purposes of the current study aims from previous mock juror research examining credibility (Henry et al 2011; Mueller-Johnson et al 2007), and blameworthiness, guilt and sentencing leniency (Mowle et al 2016; Wiley and Bottoms 2009). Following each rating participants were asked to provide qualitative responses regarding why they gave that rating (e.g., ‘Why did you give this rating of likeability?…”

Perceptions of Mental Health Conditions in Criminal Cases: A Survey Study Involving Swedish Lay Judges

“…In all study conditions, participants received the same crime vignette (104 words long; see Appendix) adopted from previous research (Mowle et al, 2016). The case described a street robbery, where a female pedestrian ("Mrs. K") was approached by a stranger ("Stenberg") who grabbed her handbag and slashed her across the face with a pocket knife.…”

“…Neurobiological research has demonstrated that decisions are influenced by both fast (i.e., unconscious) and slow (i.e., conscious and influenced by culture and education) aspects (Frith & Singer, 2008). Previous research has also demonstrated that political affiliation might impact legal decision-making (Mowle et al, 2016). Social and cognitive psychology is ripe with theories and evidence regarding reasoning and decision-making processes, however, the application of these theories to the study of professional judges and lay judges is lacking.…”