Neuroscientific and Genetic Evidence in Criminal Cases: A Double-Edged Sword in Germany but Not in the United States?

Daniela Guillen Gonzalez; Merlin Bittlinger; Susanne Erk; Sabine Müller

doi:10.3389/fpsyg.2019.02343

Frontiers in Psychology (Oct 2019)

Neuroscientific and Genetic Evidence in Criminal Cases: A Double-Edged Sword in Germany but Not in the United States?

Daniela Guillen Gonzalez,
Merlin Bittlinger,
Susanne Erk,
Sabine Müller

Affiliations

Daniela Guillen Gonzalez: Research Division of Mind and Brain Research, Department of Psychiatry and Psychotherapy CCM, Berlin Institute of Health, Humboldt University of Berlin, Corporate Member of the Free University of Berlin, Charité – Berlin University of Medicine, Berlin, Germany
Merlin Bittlinger: QUEST – Center for Transforming Biomedical Research, Berlin Institute of Health, Berlin, Germany
Susanne Erk: Research Division of Mind and Brain Research, Department of Psychiatry and Psychotherapy CCM, Berlin Institute of Health, Humboldt University of Berlin, Corporate Member of the Free University of Berlin, Charité – Berlin University of Medicine, Berlin, Germany
Sabine Müller: Research Division of Mind and Brain Research, Department of Psychiatry and Psychotherapy CCM, Berlin Institute of Health, Humboldt University of Berlin, Corporate Member of the Free University of Berlin, Charité – Berlin University of Medicine, Berlin, Germany

DOI: https://doi.org/10.3389/fpsyg.2019.02343
Journal volume & issue: Vol. 10

Abstract

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Aim of the StudyThe study examines how neurobiological and genetic explanations of psychopathy influence decision-making of German law students about legal and moral responsibility and sentencing of a defendant in a case of manslaughter. Previous studies from the United States and Germany have been criticized because they partly contradict legal analyses of real-world criminal cases. With a modified design, which integrates the main criticism, we re-examined the impact of biological explanations for psychopathy on decision-making in the courtroom.MethodsWe developed an improved quasi-experimental design to probe three case vignettes presenting different explanations of psychopathy in a criminal case of manslaughter. All three vignettes present the same information about a forensic expert’s testimony that is said to report compelling evidence for the diagnosis of “psychopathy.” The independent variable being manipulated is the type of information supporting the expert diagnosis: either no biological explanation of “psychopathy” versus a neurological explanation (brain injury) versus a genetic explanation (MAOA gene). The outcome measure is a questionnaire on legal and moral responsibility, free will, the type of custody, and the duration of the sentence. The study is adequately powered. We openly publish the data and all statistical analyses as reproducible R scripts.ResultsThe answers of German law students (n = 317) indicate that the omission of a neurobiological explanation is significantly associated with higher ratings of legal responsibility while compared to no biological explanation. However, there was no significant difference on the prison sentencing and type of custody assigned. Furthermore, there was no difference in the self-reported impact of the explanation of psychopathy on the participants’ decision-making.ConclusionOur findings from German law students corroborates previous research on German judges but is markedly distinct from studies on United States judges. Whereas in the United States, biological information seems to have a mitigating effect, it seems to increase the rate of involuntary commitment to forensic psychiatric hospitals in Germany.

Published in Frontiers in Psychology

ISSN: 1664-1078 (Online)
Publisher: Frontiers Media S.A.
Country of publisher: Switzerland
LCC subjects: Philosophy. Psychology. Religion: Psychology
Website: https://www.frontiersin.org/journals/psychology

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