Effects of neuroimaging evidence on mock juror 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.

The use of neurobiological evidence in sentencing mitigation

Neurobiological evidence has grown increasingly relevant in U.S. criminal proceedings, particularly during sentencing. Neuroimaging, such as functional Magnetic Resonance Imaging and Positron Emission Tomography scans, may be introduced by defense counsel to demonstrate brain abnormalities to argue for more lenient sentencing. This practice is common for penalty mitigation in cases eligible for capital punishment. This article reviews the history of the use of neuroscience in criminal cases from the early 20th Century to present, noting pertinent legal and ethical considerations for the use of such evidence. The authors review important empirical research conducted in recent years regarding the use of neurobiological evidence in legal proceedings (such as mock-juror studies) and guidance from the federal sentencing guidelines and the American Bar Association. The discussion also notes relevant case law in which neuroimaging, behavioral genetics, or other neurobiological data were introduced in criminal proceedings, particularly precedent-setting U.S. Supreme Court cases.

Neuroethics and neurolaw in forensic neuropsychiatry: A guide for clinicians

As neuroscience technologies develop, ethical and legal questions arise regarding their use and societal impact. Neuroethics and neurolaw are growing interdisciplinary fields that address these questions. This review article presents the research agenda of both areas, examines the use and admissibility of neuroscience in expert testimony and legal settings, and discusses ethical issues related to forensic neuropsychiatrists claiming expertise in neuroscience, formulating medical opinions based on neuroscience, and considering its relevance to criminal responsibility. Forensic neuropsychiatrists should be aware of emerging neuroscientific evidence, its utility and limits in rendering diagnoses and explaining behavior, and, before seeking such evidence for legal purposes, its availability and admissibility. When testifying in matters involving neuroscientific evidence, ensuring truthfulness and balance, having sufficient and validated knowledge (including openness with confirming and disconfirming evidence), understanding standards of practice, and drawing relevant and appropriate conclusions remain important.

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.

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."

Juror decision-making regarding a defendant diagnosed with borderline personality disorder

Stigma is an established consequence of the Borderline Personality Disorder (BPD) diagnosis. This diagnosis is subject to revision in the International Classification of Diseases-11th Revision (ICD-11). Using the legal issue of diminished responsibility, this study applied an experimental mock-jury methodology to explore the impact of diagnostic stigma of BPD on jury decision-making. Participants were allocated to one of two versions of a simplified fictitious homicide trial. The group whose defendant was described as having a 'severe personality disorder, borderline pattern' rated the defendant as more dangerous, and more in need of segregation and coercive treatment, than controls where the defendant was described as having a 'complex mental health problem'. Between-group differences in other measures, including the decision to agree a verdict of diminished responsibility, were not found. The ICD-11 'severe personality disorder, borderline pattern' diagnosis may adversely impact the attitudes of jurors considering the question of diminished responsibility.

Neuroscience literacy and substance use prevention: How well do young people understand their brain?

ISSUE

Reducing substance use harm in young people is a major public health priority, however, health promotion messages often struggle to achieve meaningful engagement. Neuroscience-based teachings may provide an innovative new way to engage young people in credible harm minimisation health promotion. This study aims to evaluate the acceptability and credibility of a series of neuroscience-based drug education animations and investigate neuroscience literacy in young people.

METHODS

Three animations were developed around the impact of alcohol, MDMA and cannabis use on the growing brain, labelled the 'Respect Your Brain' video series. Sixty young people (mean age 21.9 years; 48% female) viewed the animations and completed a 20-minute web-based, self-report survey to provide feedback on the animations and a 19-item neuroscience literacy survey, assessing knowledge and attitudes towards the brain.

RESULTS

The Alcohol, Cannabis and MDMA videos were rated as good or very good by the majority of participants (82%, 89% and 85%, respectively) and all participants wanted to see more 'Respect your Brain' videos. On average the Alcohol, Cannabis and MDMA videos were rated as containing the right level of detail and being interesting, relevant and engaging by the majority of participants (80%, 81% and 83%, respectively). Participants scored an average of 74% in the neuroscience literacy questionnaire, demonstrating some knowledge of brain functioning and positive attitudes towards the brain.

CONCLUSION

This study provides evidence that age-appropriate, neuroscience-based resources on alcohol, Cannabis and MDMA are engaging and relevant to young people and offer a potential new avenue to reduce alcohol and other drug related harm and promote healthy lifestyle choices in young people.

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.

A pilot study of a neuroscience-based, harm minimisation programme in schools and youth centres in Australia

OBJECTIVES

The primary aim is to evaluate the feasibility of a newly developed, neuroscience-based, alcohol and other drug (AOD) use prevention programme, 'The Illicit Project', in Australian older adolescents. The secondary aim is to investigate the impact of the programme on students' drug literacy levels (a combination of knowledge, attitudes and skills).

DESIGN

A pilot study examining the feasibility of The Illicit Project in Australian schools was conducted.

PARTICIPANTS

Students aged 15-19 years from two secondary schools and a youth centre and 11 teachers and health professionals from various organisations in Sydney were recruited.

INTERVENTION

The intervention consisted of three 90 min workshops delivered by trained facilitators within a month.

PRIMARY AND SECONDARY MEASURES

Students completed a drug literacy questionnaire before and after intervention. All participants (students, teachers and health professionals) completed an evaluation questionnaire postprogramme delivery. A paired-sample t-test and descriptive analytics were performed.

RESULTS

Students (n=169) demonstrated a significant increase in drug literacy levels from preintervention to postintervention (t(169) = -13.22, p<0.0001). Of students evaluating the programme (n=252), over threequarters agreed that The Illicit Project was good or very good (76%), that the neuroscience content was interesting (76%) and relevant (81%), and that they plan to apply the concepts learnt to their own lives (80%). In addition, all teachers and health professionals (n=11) agreed that the programme was feasible and valid for schools and perceived the programme to be effective in reducing the harms and use of AOD.

CONCLUSIONS

There is evidence to suggest that The Illicit Project is credible and feasible in the school environment and there are preliminary data to suggest it may help to improve drug literacy levels in young people. A large-scale evaluation trial of the intervention will be conducted to determine the programme's effectiveness in minimising the harms of AOD in older adolescents.

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.

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

Aim of the Study

The 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.

Methods

We 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.

Results

The 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.

Conclusion

Our 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.

Does It Matter Whether You or Your Brain Did It? An Empirical Investigation of the Influence of the Double Subject Fallacy on Moral Responsibility Judgments

Despite progress in cognitive neuroscience, we are still far from understanding the relations between the brain and the conscious self. We previously suggested that some neuroscientific texts that attempt to clarify these relations may in fact make them more difficult to understand. Such texts-ranging from popular science to high-impact scientific publications-position the brain and the conscious self as two independent, interacting subjects, capable of possessing opposite psychological states. We termed such writing 'Double Subject Fallacy' (DSF). We further suggested that such DSF language, besides being conceptually confusing and reflecting dualistic intuitions, might affect people's conceptions of moral responsibility, lessening the perception of guilt over actions. Here, we empirically investigated this proposition with a series of three experiments (pilot and two preregistered replications). Subjects were presented with moral scenarios where the defendant was either (1) clearly guilty, (2) ambiguous, or (3) clearly innocent while the accompanying neuroscientific evidence about the defendant was presented using DSF or non-DSF language. Subjects were instructed to rate the defendant's guilt in all experiments. Subjects rated the defendant in the clearly guilty scenario as guiltier than in the two other scenarios and the defendant in the ambiguously described scenario as guiltier than in the innocent scenario, as expected. In Experiment 1 (N = 609), an effect was further found for DSF language in the expected direction: subjects rated the defendant less guilty when the neuroscientific evidence was described using DSF language, across all levels of culpability. However, this effect did not replicate in Experiment 2 (N = 1794), which focused on different moral scenario, nor in Experiment 3 (N = 1810), which was an exact replication of Experiment 1. Bayesian analyses yielded strong evidence against the existence of an effect of DSF language on the perception of guilt. Our results thus challenge the claim that DSF language affects subjects' moral judgments. They further demonstrate the importance of good scientific practice, including preregistration and-most critically-replication, to avoid reaching erroneous conclusions based on false-positive results.

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.

Reconciling the opposing effects of neurobiological evidence on criminal sentencing judgments

Legal theorists have characterized physical evidence of brain dysfunction as a double-edged sword, wherein the very quality that reduces the defendant’s responsibility for his transgression could simultaneously increase motivations to punish him by virtue of his apparently increased dangerousness. However, empirical evidence of this pattern has been elusive, perhaps owing to a heavy reliance on singular measures that fail to distinguish between plural, often competing internal motivations for punishment. The present study employed a test of the theorized double-edge pattern using a novel approach designed to separate such motivations. We asked a large sample of participants (N = 330) to render criminal sentencing judgments under varying conditions of the defendant’s mental health status (Healthy, Neurobiological Disorder, Psychological Disorder) and the disorder’s treatability (Treatable, Untreatable). As predicted, neurobiological evidence simultaneously elicited shorter prison sentences (i.e., mitigating) and longer terms of involuntary hospitalization (i.e., aggravating) than equivalent psychological evidence. However, these effects were not well explained by motivations to restore treatable defendants to health or to protect society from dangerous persons but instead by deontological motivations pertaining to the defendant’s level of deservingness and possible obligation to provide medical care. This is the first study of its kind to quantitatively demonstrate the paradoxical effect of neuroscientific trial evidence and raises implications for how such evidence is presented and evaluated.

Judges' perceptions of expert reports: The effect of neuroscience evidence

This article explores the impact of neuroscience evidence on how expert reports are perceived and their effects on the decisions made by trial judges. Experimental psychology has demonstrated a number of cognitive effects arising from exposure to neuroimaging data which may bias judgments and lead to (mis)interpretations that can affect decisions. We conducted a study on a sample of 62 Swiss and French judges in order to determine whether their perceptions of the credibility, quality and scientific basis of a psychiatric evaluation of a criminal defendant vary according to whether or not the evaluation includes neuroscientific data. Quantitative analyses were conducted in order to evaluate significant differences between the two conditions (one-way analyses of variance) and moderation and conditional analyses to examine whether the participants' sex and length of professional experience moderated the effect of the conditions. Terminological and thematic analyses were carried out on open questions. Quantitative and qualitative results suggest that the presence of neuroscience data in an expert report affects judges' perceptions of the quality, credibility, and scientificity (reliability, objectivity, scientific basis) of the report, and the persuasiveness of the evidence it provided. Moreover, this phenomenon was stronger in more experienced judges than in less experienced judges.

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.

Free Will and the Brain Disease Model of Addiction: The Not So Seductive Allure of Neuroscience and Its Modest Impact on the Attribution of Free Will to People with an Addiction

Free will has been the object of debate in the context of addiction given that addiction could compromise an individual's ability to choose freely between alternative courses of action. Proponents of the brain-disease model of addiction have argued that a neuroscience perspective on addiction reduces the attribution of free will because it relocates the cause of the disorder to the brain rather than to the person, thereby diminishing the blame attributed to the person with an addiction. Others have worried that such displacement of free will attribution would make the person with a drug addiction less responsible. Using the paradigmatic literature on the seductive allure of neuroscience explanations, we tested whether neuroscience information diminishes attributions of free will in the context of addiction and whether respondent characteristics influence these attributions and modulate the effect of neuroscience information. We performed a large-scale, web-based experiment with 2,378 German participants to explore how attributions of free will in the context of addiction to either alcohol or cocaine are affected by: (1) a text with a neurobiological explanation of addiction, (2) a neuroimage showing effects of addiction on the brain, and (3) a combination of a text and a neuroimage, in comparison to a control group that received no information. Belief in free will was measured using the FAD-Plus scale and was, subsequent to factor analysis, separated into two factors: responsibility and volition. The investigated respondent characteristics included gender, age, education, self-reported knowledge of neuroscience, substance-use disorder (SUD), and having a friend with SUD. We found that attributions of volition (in the cocaine-subsample) were reduced in the text and neuroimage-treatment compared to the control group. However, respondent characteristics such as education and self-reported knowledge of neuroscience were associated with lower attributions of responsibility for both substances, and education was associated with lower attribution of volition for the alcohol sub-sample. Interaction analyses showed that knowledge of neuroscience was found to generally decrease attribution of responsibility. Further research on attribution of free will should consider the effects of context and respondent characteristics, which appeared surprisingly larger than those induced by experimental treatments.

Communicating the Neuroscience of Psychopathy and Its Influence on Moral Behavior: Protocol of Two Experimental Studies

Neuroscience has identified brain structures and functions that correlate with psychopathic tendencies. Since psychopathic traits can be traced back to physical neural attributes, it has been argued that psychopaths are not truly responsible for their actions and therefore should not be blamed for their psychopathic behaviors. This experimental research aims to evaluate what effect communicating this theory of psychopathy has on the moral behavior of lay people. If psychopathy is blamed on the brain, people may feel less morally responsible for their own psychopathic tendencies and therefore may be more likely to display those tendencies. An online study will provide participants with false feedback about their psychopathic traits supposedly based on their digital footprint (i.e., Facebook likes), thus classifying them as having either above-average or below-average psychopathic traits and describing psychopathy in cognitive or neurobiological terms. This particular study will assess the extent to which lay people are influenced by feedback regarding their psychopathic traits, and how this might affect their moral behavior in online tasks. Public recognition of these potential negative consequences of neuroscience communication will also be assessed. A field study using the lost letter technique will be conducted to examine lay people's endorsement of neurobiological, as compared to cognitive, explanations of criminal behavior. This field and online experimental research could inform the future communication of neuroscience to the public in a way that is sensitive to the potential negative consequences of communicating such science. In particular, this research may have implications for the future means by which neurobiological predictors of offending can be safely communicated to offenders.

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

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.

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

Demonstrations of a link between genetic variants and criminal behavior have stimulated increasing use of genetic evidence to reduce perceptions of defendants' responsibility for criminal behavior and to mitigate punishment. However, because only limited data exist regarding the impact of such evidence on decision makers and the public at large, we recruited a representative sample of the U.S. adult population (n=960) for a web-based survey. Participants were presented with descriptions of three legal cases and were asked to: determine the length of incarceration for a convicted murderer; adjudicate an insanity defense; and decide whether a defendant should receive the death penalty. A fully crossed, between-participants, factorial design was used, varying the type of evidence (none, genetic, neuroimaging, both), heinousness of the crime, and past criminal record, with sentence or verdict as the primary outcome. Also assessed were participants' apprehension of the defendant, belief in free will, political ideology, and genetic knowledge. Across all three cases, genetic evidence had no significant effects on outcomes. Neuroimaging data showed an inconsistent effect in one of the two cases in which it was introduced. In contrast, heinousness of the offense and past criminal record were strongly related to participants' decisions. Moreover, participants' beliefs about the controllability of criminal behavior and political orientations were significantly associated with their choices. Our findings suggest that neither hopes that genetic evidence will modify judgments of culpability and punishment nor fears about the impact of genetic evidence on decision makers are likely to come to fruition.

The selective allure of neuroscientific explanations

Some claim that recent advances in neuroscience will revolutionize the way we think about human nature and legal culpability. Empirical support for this proposition is mixed. Two highly-cited empirical studies found that irrelevant neuroscientific explanations and neuroimages were highly persuasive to laypersons. However, attempts to replicate these effects have largely been unsuccessful. Two separate experiments tested the hypothesis that neuroscience is susceptible to motivated reasoning, which refers to the tendency to selectively credit or discredit information in a manner that reinforces preexisting beliefs. Participants read a newspaper article about a cutting-edge neuroscience study. Consistent with the hypothesis, participants deemed the hypothetical study sound and the neuroscience persuasive when the outcome of the study was congruent with their prior beliefs, but gave the identical study and neuroscience negative evaluations when it frustrated their beliefs. Neuroscience, it appears, is subject to the same sort of cognitive dynamics as other types of scientific evidence. These findings qualify claims that neuroscience will play a qualitatively different role in the way in which it shapes people’s beliefs and informs issues of social policy.

On the (non) persuasive power of a brain image

The persuasive power of brain images has captivated scholars in many disciplines. Like others, we too were intrigued by the finding that a brain image makes accompanying information more credible (McCabe & Castel in Cognition 107:343-352, 2008). But when our attempts to build on this effect failed, we instead ran a series of systematic replications of the original study-comprising 10 experiments and nearly 2,000 subjects. When we combined the original data with ours in a meta-analysis, we arrived at a more precise estimate of the effect, determining that a brain image exerted little to no influence. The persistent meme of the influential brain image should be viewed with a critical eye.

Visual attention and the neuroimage bias

Several highly-cited experiments have presented evidence suggesting that neuroimages may unduly bias laypeople’s judgments of scientific research. This finding has been especially worrisome to the legal community in which neuroimage techniques may be used to produce evidence of a person’s mental state. However, a more recent body of work that has looked directly at the independent impact of neuroimages on layperson decision-making (both in legal and more general arenas), and has failed to find evidence of bias. To help resolve these conflicting findings, this research uses eye tracking technology to provide a measure of attention to different visual representations of neuroscientific data. Finding an effect of neuroimages on the distribution of attention would provide a potential mechanism for the influence of neuroimages on higher-level decisions. In the present experiment, a sample of laypeople viewed a vignette that briefly described a court case in which the defendant’s actions might have been explained by a neurological defect. Accompanying these vignettes was either an MRI image of the defendant’s brain, or a bar graph depicting levels of brain activity–two competing visualizations that have been the focus of much of the previous research on the neuroimage bias. We found that, while laypeople differentially attended to neuroimagery relative to the bar graph, this did not translate into differential judgments in a way that would support the idea of a neuroimage bias.

Look Again: Effects of Brain Images and Mind–Brain Dualism on Lay Evaluations of Research

Brain scans have frequently been credited with uniquely seductive and persuasive qualities, leading to claims that fMRI research receives a disproportionate share of public attention and funding. It has been suggested that functional brain images are fascinating because they contradict dualist beliefs regarding the relationship between the body and the mind. Although previous research has indicated that brain images can increase judgments of an article's scientific reasoning, the hypotheses that brain scans make research appear more interesting, surprising, or worthy of funding have not been tested. Neither has the relation between the allure of brain imaging and dualism. In the following three studies, laypersons rated both fictional research descriptions and real science news articles accompanied by brain scans, bar charts, or photographs. Across 988 participants, we found little evidence of neuroimaging's seductive allure or of its relation to self-professed dualistic beliefs. These results, taken together with other recent null findings, suggest that brain images are less powerful than has been argued.

Opportunities, threats and limitations of neuroscience data in forensic psychiatric evaluation

PURPOSE OF REVIEW

In the last decade, a number of studies have been published to shed light on the interaction between neuroscience and the law, notably on the introduction of neuroscience data in forensic psychiatric evaluation (FPE). Even if there is a growing consensus on the relevance of neuroscience in clinical practice, the role of neuroscience in FPE is still controversial.

RECENT FINDINGS

The use of neuroscience data in FPE can support the detection of psychopathological disabilities (e.g. deficit of self-control, aggressiveness) that may be involved in criminal action. Traumatic brain injury-related clinical disorders that may lead to misconduct have a relevant role in the debate. Traditionally, literature refers also to rare and weird cases in which brain tumours, infections and morphological abnormalities were supposed to be significantly associated with disorders leading to criminal action.

SUMMARY

After reviewing recent literature from both legal and neuroscientific perspectives, we consider a broader range of clinical conditions (e.g. disorders of consciousness in sleepwalking, dopamine replacement therapy in Parkinson's disease, misattributions of self in delusional experience) that may have implications in legal settings. Obviously, it would be possible to consider also different clinical conditions. We conclude by suggesting further experimental and theoretical analysis.

Neuroimages in court: less biasing than feared

Neuroscience is increasingly poised to play a role in legal proceedings. One persistent concern, however, is the intuition that brain images may bias, mislead, or confuse jurors. Initially, empirical research seemed to support this intuition. New findings contradict those expectations, prompting a rethinking of the 'threat' of neuroscience in the courtroom.