Effects of Behavioral Genetic Evidence on Perceptions of Criminal Responsibility and Appropriate Punishment

Bio-behavioral scientific evidence alters judges' sentencing decision-making: A quantitative analysis

The present study surveyed judges to examine how they consider and apply scientific information during sentencing determinations. Judges in criminal courts are increasingly asked to assess and make decisions based on evidence surrounding psychiatric disorders, with unclear results on sentencing outcomes. We qualitatively interviewed 34 judges who have presided over criminal cases in 16 different states and also administered vignette surveys during the interviews. We asked them to make sentencing decisions for hypothetical defendants in cases presenting evidence of either no psychiatric disorder, an organic brain disorder, or past trauma, as well as to rate the importance of different goals of sentencing for each case. Results indicated that the case presenting no evidence of a mental health condition received significantly more severe sentences as compared to either psychiatric condition. Judges' ratings of sentencing goals showed that the importance of retribution was a significant mediator of this relationship. Trauma was not deemed to be as mitigating as an organic brain disorder. These results provide unique insights into how judges assess cases and consider sentencing outcomes when presented with scientific information to explicate defendants' behavior. We propose ways forward that may help better integrate scientific understandings of behavior into criminal justice decision-making.

Neuroscience explanations really do satisfy: A systematic review and meta-analysis of the seductive allure of neuroscience

Extraneous neuroscience information improves ratings of scientific explanations, and affects mock juror decisions in many studies, but others have yielded little to no effect. To establish the magnitude of this effect, we conducted a random-effects meta-analysis using 60 experiments from 28 publications. We found a mild but highly significant effect, with substantial heterogeneity. Planned subgroup analyses revealed that within-subjects studies, where people can compare the same material with and without neuroscience, and those using text, have stronger effects than between-subjects designs, and studies using brain image stimuli. We serendipitously found that effect sizes were stronger on outcomes of evaluating satisfaction or metacomprehension, compared with jury verdicts or assessments of convincingness. In conclusion, there is more than one type of neuroscience explanations effect. Irrelevant neuroscience does have a seductive allure, especially on self-appraised satisfaction and understanding, and when presented as text.

Genetic essentialist beliefs about criminality predict harshness of recommended punishment

Genetic essentialism is a set of beliefs holding that certain categories have a heritable, intrinsic, and biological basis. The current studies explore people's genetic essentialist beliefs about criminality, how such essentialism relates to beliefs about appropriate punishment, and the kinds of judgments and motivations that underlie these associations. Study 1 validated a novel task, in which respondents estimated how possible it would be for a child to inherit criminal behavior from a sperm donor with whom they had no contact. Studies 2-4 used this task to address how genetic essentialist beliefs related to the harmfulness of a crime and the harshness of recommended punishment. Results indicated a tendency to essentialize both low- and high-harm crimes, though genetic essentialism was higher for more harmful crimes. Moreover, genetic essentialist beliefs predicted recommendations for harsher punishments, with retributive and protective motivations, as well as perceptions of recidivism risk, partially mediating this association. Further, Studies 3 and 4 found that genetic essentialism positively predicted support for harsh punishments such as the death penalty, as well as support for directing financial resources more toward law enforcement and less toward social support. Lay theories about criminality may have profound implications for decisions about appropriate punishment for wrongdoers, as well as broader policy decisions about crime, punishment, and resource allocation. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The effect of neuroscientific evidence on sentencing depends on how one conceives of reasons for incarceration

Neuroscientific evidence is increasingly utilized in criminal legal proceedings, prompting discussions about how such evidence might influence legal decisions. The effect of neuroscientific testimony on legal decisions remains uncertain, with some studies finding no effect, others reporting that neuroscience has a mitigating impact, and some indicating neuroscience evidence has an aggravating effect. The present study attempts to explain these divergent findings by showing that the effect of neuroscience evidence on sentencing interacts with beliefs about the goals of the criminal legal system. Using a between-subjects design, participants (N = 784) were asked to assume different rationales for imprisonment, before receiving neuroscientific evidence about antisocial behavior and its potential relation to the defendant. Participants recommended a sentence for the defendant prior to and after reading the neuroscientific evidence. Participants who were given the rationale of retribution as the primary goal of imprisonment significantly decreased their sentencing recommendations. When the goal of imprisonment was to protect the public from dangerous people, participants provided longer post-testimony sentences. Lastly, when the goal was to rehabilitate wrongdoers, participants also increased sentences from pre to post. Thus, the impact of neuroscientific evidence is not monolithic, but can lead to either mitigated or aggravated sentences by interacting with penal philosophy.

A jury of scientists: Formal education in biobehavioral sciences reduces the odds of punitive criminal sentencing

This study examines how formal education in biological and behavioral sciences may impact punishment intuitions (views on criminal sentencing, free will, responsibility, and dangerousness) in cases involving neurobiological evidence. In a survey experiment, we compared intuitions between biobehavioral science and non-science university graduates by presenting them with a baseline case without a neurobiological explanation for offending followed by one of two cases with a neurobiological explanation (described as either innate or acquired biological influences to offending). An ordinal logistic regression indicated that both science and non-science graduates selected significantly more severe punishments for the baseline case as compared to when an innate neurobiological explanation for offending was provided. However, across all cases, science graduates selected significantly less severe sentences than non-science graduates, and only science graduates' decisions were mediated by free will and responsibility attributions. Findings are discussed in relation to scientific understandings of behavior, the impact of science education on attitudes towards punishment, and potential criminal-legal implications.

Losing the lottery of life: Examining intuitions of desert toward the socially and genetically "unlucky" in criminal punishment contexts

This research presents three experiments that examine how natural "luck" (social and genetic luck) may affect lay intuitions toward desert-based criminal punishment. Study 1 examined if intuitions surrounding desert-based rewards in relation to good qualities/advantages ascribed to natural luck would extend to desert-based punishments in relation to bad qualities/disadvantages ascribed to natural luck. Study 2 examined how both social and genetic luck affect support for desert-based punishment across different criminal offenses and tests the relevance of immanent justice reasoning to such support. Study 3 examined whether findings in the prior studies are specific to desert-based punishment and immanent justice reasoning, or if natural luck elicits broader punishment judgments and types of justice reasoning. Results showed that known intuitions surrounding desert-based rewards do extend to desert-based punishments in instances of natural luck. Immanent justice reasoning was strongly associated with support for desert-based punishment in instances of both social and genetic luck. However, genetic luck, as compared to social luck, significantly increased support for desert-based punishment, with imminent justice reasoning mediating this increased support. Implications are discussed in relation to capital sentencing and better understanding lay intuitions toward the punishment of criminal offenders who may have qualities ascribed to the "natural lottery."

Fight, flight, and free will: The effect of trauma informed psychoeducation on perceived culpability and punishment for juvenile and adult offenders

Justifications for punishment are generally grounded in retribution or consequentialism. Retribution is rooted in and legitimized by common sense notions of free will, claiming that offenders freely and rationally choose to commit a criminal act, and are therefore deserving of punishment. Consequentialism does not necessitate a reliance on a belief in free will, and views punishment as means to a valuable end. In recent years, neuroscientific research has challenged the notion of free will, providing one pathway for a public shift away from retribution and towards consequentialism. To date, no studies have examined whether educating participants about biopsychosocial effects of trauma that are often outside of conscious awareness may contribute to free will doubt. This study used a 2 (biopsychosocial information, neutral information) × 2 (juvenile offender, adult offender) between subjects design and measured beliefs in free will, judgments of culpability, and justifications for punishment. Results showed a main effect of trauma informed psychoeducation on free will beliefs, such that individuals who watched a trauma video had lower free will beliefs compared to individuals who watched a control video. Direct effects of trauma informed psychoeducation on sentence severity and on justifications for punishment were nonsignificant. However, mediation analyses revealed that free will beliefs had an indirect effect on the relations between trauma informed psychoeducation and perceived culpability and that perceived culpability had an indirect effect on the relations between trauma informed psychoeducation and retribution, consequentialism, and punishment severity.

The effects of essentialist thinking toward biosocial risk factors for criminality and types of offending on lay punishment support

This research uses experimental methods to gauge how different facets of essentialist thinking toward (1) types of offending and (2) biosocial risk factors for criminality predict lay punishment support. A randomized between-subjects experiment using contrastive vignettes was conducted with members of the general public (N = 897). Overall, as hypothesized, aspects of essentialist thinking, particularly informativeness, continuity, immutability, and discreteness, toward both biosocial risk factors and types of offending behavior generally predicted more severe punishments surrounding retribution, incapacitation, and deterrence. Yet, surprisingly, several of the same beliefs, specifically toward discreteness and informativeness, also predicted non-punitive sentiments toward restoration and decreased prison time in some contexts. This work demonstrates that essentialist thinking not only may affect how the public cognitively categorizes biosocial risk factors for criminality and types of offending, but also may have consequences for public support for the punishment of offenders with particular offense records or characteristics.

Neuroscientific evidence in the courtroom: a review

The use of neuroscience in the courtroom can be traced back to the early twentieth century. However, the use of neuroscientific evidence in criminal proceedings has increased significantly over the last two decades. This rapid increase has raised questions, among the media as well as the legal and scientific communities, regarding the effects that such evidence could have on legal decision makers. In this article, we first outline the history of neuroscientific evidence in courtrooms and then we provide a review of recent research investigating the effects of neuroscientific evidence on decision-making broadly, and on legal decisions specifically. In the latter case, we review studies that measure the effect of neuroscientific evidence (both imaging and nonimaging) on verdicts, sentencing recommendations, and beliefs of mock jurors and judges presented with a criminal case. Overall, the reviewed studies suggest mitigating effects of neuroscientific evidence on some legal decisions (e.g., the death penalty). Furthermore, factors such as mental disorder diagnoses and perceived dangerousness might moderate the mitigating effect of such evidence. Importantly, neuroscientific evidence that includes images of the brain does not appear to have an especially persuasive effect (compared with other neuroscientific evidence that does not include an image). Future directions for research are discussed, with a specific call for studies that vary defendant characteristics, the nature of the crime, and a juror’s perception of the defendant, in order to better understand the roles of moderating factors and cognitive mediators of persuasion.

Mosaic trisomy 20 and mitigation in capital crimes sentencing: A review and case report

Trisomy 20 is a genetic abnormality in which individuals have an extra copy of chromosome 20. Complete trisomy 20 is rare and believed to be incompatible with life. A mosaic form of trisomy 20, in which only some cells or tissues contain the extra chromosome, is a relatively commonly encountered chromosomal abnormality found during prenatal testing, and c. 90% result in a normal phenotype. However, despite the absence of a consistent phenotype, certain findings have been reported across multiple cases of mosaic trisomy 20. These include an array of morphological findings, developmental delays, and learning disabilities. Beyond physical manifestations, a wide range of developmental and learning delays have also been reported. In this work, we provide an overview of the trisomy 20 literature and a case report of a young adult male with mosaic trisomy 20 who committed homicide. His developmental and life history, eventual diagnosis of mosaic trisomy 20, similarities and differences in his condition compared with prior research findings, and potentially new phenotypic findings associated with trisomy 20 that he manifested (childhood visual hallucinations, self-injury, polydactyly) are presented. Additionally, the potential role of this genetic diagnosis in his neuropsychiatric history and its successful application as a mitigating factor at his capital sentencing trial are described. We did not identify other similar cases during our search of major scientific and legal databases. As a backdrop, the use of genetics in criminal trials is on the rise, and courts are increasingly likely to accept behavioral genetics evidence; therefore, it is crucial that the legal system is well acquainted with the opportunities and limitations of these approaches.

Asymmetrical genetic attributions for prosocial versus antisocial behaviour

Genetic explanations of human behavior are increasingly common. While genetic attributions for behavior are often considered relevant for assessing blameworthiness, it has not yet been established whether judgments about blameworthiness can themselves impact genetic attributions. Across six studies, participants read about individuals engaging in prosocial or antisocial behavior and rated the extent to which they believed that genetics played a role in causing the behavior. Antisocial behavior was consistently rated as less genetically influenced than prosocial behavior. This was true regardless of whether genetic explanations were explicitly provided or refuted. Mediation analyses suggested that this asymmetry may stem from people’s motivating desire to hold wrongdoers responsible for their actions. These findings suggest that those who seek to study or make use of genetic explanations’ influence on evaluations of (e.g., antisocial) behavior should consider whether such explanations are accepted in the first place, given the possibility of motivated causal reasoning.

Biological Evidence Regarding Psychopathy Does Not Affect Mock Jury Sentencing

Research on the biological factors influencing criminal behavior is increasingly being introduced into court, necessitating research on how such evidence is perceived and influences decision makers. Research on how this evidence influences sentencing recommendations is inconclusive. In this study, we focus on biological evidence related to psychopathy, a construct commonly associated with criminal behavior. Approximately 800 community members were presented with a case vignette detailing an individual who is described as having a high level of psychopathic traits. Participants received either psychological information about psychopathy (i.e., no biological evidence), evidence the defendant had genetic risk factors for psychopathy, or written neuroimaging evidence the defendant had brain deficits associated with psychopathy. Participants then recommended a sentence. Overall, recommended sentence lengths did not differ between evidence conditions. These findings add to a growing body of research suggesting that biological evidence may not have as much of an influence on jurors as previously thought.

Behavioral Genetics and Attributions of Moral Responsibility

While considerable research has examined how genetic explanations for behavior impact assessments of moral responsibility, results across studies have been inconsistent. Some studies suggest that genetic accounts diminish ascriptions of responsibility, but others show no effect. Nonetheless, conclusions from behavior genetics are increasingly mobilized on behalf of defendants in court, suggesting a widespread intuition that this sort of information is relevant to assessments of blameworthiness. In this paper, we consider two sorts of reasons why this kind of intuition, if it exists, is not consistently revealed in empirical studies. On the one hand, people may have complex and internally conflicting intuitions about the relationship between behavior genetics and moral responsibility. On the other hand, it may be that people are motivated to think about the role of genetics in behavior differently depending on the moral valence of the actions in question.

What difference do brain images make in US criminal trials?

One of the early concerns regarding the use of neuroscience data in criminal trials is that even if the brain images are ambiguous or inconclusive, they still might influence a jury in virtue of the fact that they appear easy to understand. By appearing visually simple, even though they are really statistically constructed maps with a host of assumptions built into them, a lay jury or a judge might take brain scans to be more reliable or relevant than they actually are. Should courts exclude brain scans for being more prejudicial than probative? Herein, we rehearse a brief history of brain scans admitted into criminal trials in the United States, then describe the results of a recent analysis of appellate court decisions that referenced 1 or more brain scans in the judicial decision. In particular, we aim to explain how courts use neuroscience imaging data: Do they interpret the data correctly? Does it seem that scans play an oversized role in judicial decision-making? And have they changed how criminal defendants are judged? It is our hope that in answering these questions, clinicians and defence attorneys will be able to make better informed decisions regarding about how to manage those incarcerated.

Behavioral Genetics in Criminal and Civil Courts

Although emerging findings in psychiatric and behavioral genetics create hope for improved prevention, diagnosis, and treatment of disorders, the introduction of such data as evidence in criminal and civil proceedings raises a host of ethical, legal, and social issues. Should behavioral and psychiatric genetic data be admissible in judicial proceedings? If so, what are the various means for obtaining such evidence, and for what purposes should its admission be sought and permitted? How could-and should-such evidence affect judicial outcomes in criminal and civil proceedings? And what are the potential implications of using behavioral and psychiatric genetic evidence for individuals and communities, and for societal values of equality and justice? This article provides an overview of the historical and current developments in behavioral genetics. We then explore the extent to which behavioral genetic evidence has-and should-affect determinations of criminal responsibility and sentencing, as well as the possible ramifications of introducing such evidence in civil courts, with a focus on tort litigation and child custody disputes. We also consider two ways in which behavioral genetic evidence may come to court in the future-through genetic theft or the subpoena of a litigant's biospecimen data that was previously obtained for clinical or research purposes-and the concerns that these possibilities raise. Finally, we highlight the need for caution and for approaches to prevent the misuse of behavioral genetic evidence in courts.

Unable or Unwilling to Exercise Self-control? The Impact of Neuroscience on Perceptions of Impulsive Offenders

In growing numbers of court cases, neuroscience is presented to document the mental state of the offender at the level of the brain. While a small body of research has documented the effects of describing the brain state of psychotic offenders, this study tested the impact of neuroscience that could apply to far more offenders; that is the neuroscience of impulse control. In this online vignette experiment, 759 participants sentenced a normally controlled or normally impulsive actor, who committed a violent offense on impulse, explained in either cognitive or neurobiological terms. Although participants considered the neurobiological actor less responsible for his impulsive disposition than the cognitive actor, the neuroscientific testimony did not affect attributions of choice, blame, dangerousness, or punishment for the criminal act. In fact, the neuroscientific testimony exacerbated the perception that the offender offended consciously and “really wanted” to offend. The described disposition of the actor was also influential: participants attributed more capacity for reform, more free choice and consequently, more blame to the normally controlled actor. Participants also attributed this actor's offending more to his social life experiences and less to his genes and brain. However, this shift in attributions was unable to explain the greater blame directed at this offender. Together, such findings suggest that even when neuroscience changes attributions for impulsive character, attributions for impulsive offending may remain unchanged. Hence this study casts doubt on the mitigating and aggravating potential of neuroscientific testimony in court.

Nature, nurture, and capital punishment: How evidence of a genetic-environment interaction, future dangerousness, and deliberation affect sentencing decisions

Research has shown that the low-activity MAOA genotype in conjunction with a history of childhood maltreatment increases the likelihood of violent behaviors. This genetic-environment (G × E) interaction has been introduced as mitigation during the sentencing phase of capital trials, yet there is scant data on its effectiveness. This study addressed that issue. In a factorial design that varied mitigating evidence offered by the defense [environmental (i.e., childhood maltreatment), genetic, G × E, or none] and the likelihood of the defendant's future dangerousness (low or high), 600 mock jurors read sentencing phase evidence in a capital murder trial, rendered individual verdicts, and half deliberated as members of a jury to decide a sentence of death or life imprisonment. The G × E evidence had little mitigating effect on sentencing preferences: participants who received the G × E evidence were no less likely to sentence the defendant to death than those who received evidence of childhood maltreatment or a control group that received neither genetic nor maltreatment evidence. Participants with evidence of a G × E interaction were more likely to sentence the defendant to death when there was a high risk of future dangerousness than when there was a low risk. Sentencing preferences were more lenient after deliberation than before. We discuss limitations and future directions.

The forensic use of behavioral genetics in criminal proceedings: Case of the MAOA-L genotype

The role of behavioral genetic evidence in excusing and mitigating criminal behavior is unclear. Research has suggested that a low activity genotype of the enzyme monoamine oxidase (MAOA-L) may increase the risk for aggressive and antisocial behavior. By examining criminal proceedings in which MAOA-L genotype evidence was introduced, we explored the forensic uses of behavioral genetic science. Westlaw and LexisNexis legal databases were electronically searched for cases from 1995 to 2016 to identify court documents from cases involving the MAOA-L genotype. Evidence of the MAOA-L genotype was included in records from 11 criminal cases (9 U.S. and 2 Italian). In the guilt phase, genotype evidence was ruled admissible in one of two cases, and may have contributed to a conviction on a lesser charge. In the sentencing phase, genotype evidence was admissible in four of five cases, one of which ended with a lesser sentence. Five cases used genotype evidence for post-conviction appeals, two of which resulted in sentence reductions. Even when charges or sentences are reduced it is difficult to gauge the effect of evidence of the MAOA-L genotype. Genotype evidence may lack persuasive effect because the impact of the allele on a particular accused is difficult to establish.

Judges' views on evidence of genetic contributions to mental disorders in court

This preliminary analysis assesses how judges view the use of behavioral genetics evidence on genetic influences to mental disorders in court. Twenty-one semi-structured interviews, analyzed using constant comparative analysis, were conducted with California trial court judges. Most judges reported the beneficial effects of this evidence being presented in court, particularly as a mitigating factor for sentencing. Yet some judges viewed it as an aggravating factor and expressed concerns about genetic privacy. Judges described initial reactions to being potentially presented with evidence on genetic influences to mental disorders as apprehension, curiosity, and sympathy. Judges also reported putting significant trust in experts on these issues. Findings suggest some judges are skeptical of this evidence, but largely open to its presentation. Sympathetic reactions may result in mitigating attitudes of some judges. As judges significantly trust experts, some judges could also be overly trusting of genetic evidence and expert opinion on these issues.

The double-edged sword of genetic accounts of criminality: causal attributions from genetic ascriptions affect legal decision making

Much debate exists surrounding the applicability of genetic information in the courtroom, making the psychological processes underlying how people consider this information important to explore. This article addresses how people think about different kinds of causal explanations in legal decision-making contexts. Three studies involving a total of 600 Mechanical Turk and university participants found that genetic, versus environmental, explanations of criminal behavior lead people to view the applicability of various defense claims differently, perceive the perpetrator's mental state differently, and draw different causal attributions. Moreover, mediation and path analyses highlight the double-edged nature of genetic attributions-they simultaneously reduce people's perception of the perpetrator's sense of control while increasing people's tendencies to attribute the cause to internal factors and to expect the perpetrator to reoffend. These countervailing relations, in turn, predict sentencing in opposite directions, although no overall differences in sentencing or ultimate verdicts were found.