The blunt-edged sword: genetic explanations of misbehavior neither mitigate nor aggravate punishment

Abstract

Links between genetic variants and negatively valenced behaviors have stimulated intense commentary about the implications for responsibility and punishment. Previous research has suggested that behavioral genetic evidence of a predisposition to negative behaviors has modest to no impact on mitigation of punishment, at least for serious crimes. Data are presented on the effect of such evidence in a representative sample of the general population (n=640) asked to consider 3 vignettes describing lesser offenses, dealt with in less-formal adjudicatory settings and in everyday life. Genetic explanations of behavior had no effect on the severity of the punishment selected in any case, in contrast to the egregiousness of the behavior and respondents’ beliefs in free-will. Public views of genetic influences on behavior may be less deterministic and more nuanced than is often thought, or genetic explanations may simply not have the salience for decision makers that is frequently attributed to them.

Behavioural genetics in criminal court

“…(8) Across eight separate experiments, behavioral genetic evidence had no effect one way or another on perceptions of responsibility or on the degree to which individuals should be punished for misbehavior. However, the studies did consistently find that both the egregiousness of the behavior and the strength of participants’ beliefs in free will increased the magnitude of the punishments they levied.…”

Behavioral Genetics in Criminal and Civil Courts

“…78,79 Yet no such finding emerged from American studies of representative samples of the general public, who were presented with genetic evidence (as well as a combination of genetic and neuroimaging evidence) in hypothetical capital and non-capital cases. 80,81 This remained true even when respondents were asked to consider a vignette involving a lesser offense (assault with a deadly weapon) 82 and when neurogenetic findings were introduced along with evidence of an interaction between a genetic propensity and child abuse 81,82 —a key finding in the literature on genetic predisposition to antisocial behavior and violence.…”

“…83 Some support for this view may be found in the studies of the general public: participants who were more skeptical about free will were more inclined to treat MAOA evidence as a mitigating factor. 80,82 Yet this position is at odds with other theories of justice that prioritize deterrence and incapacitation—the need to protect the general public by removing offenders from society—as purposes of criminal law.…”

“…This possibility would coincide with the findings of studies of judges and the public, in which consideration of behavioral genetic evidence for mitigation generated a more medicalized approach to defendants. 78,82 It would also be in accord with the hopes that growing genomic knowledge could lead to better and more tailored treatment options for individual offenders, which could include the development of rehabilitation programs that individualize behavioral and environmental interventions to defendants’ genetic makeup. 84 Whether this approach would better serve justice, however, may be open for debate.…”

“…Studies indicate that actors in the judicial process—that is, judges, jurors, and experts who testify in court—have limited genetic knowledge, 104–106 and that genetic determinism with regard to health status is prevalent among the general public. 82,107 Insofar as these participants and fact-finders construed genetic predisposition for behavioral and psychiatric disorders—in this case aggressive behavior—as establishing sufficient foreseeability of harm, the determination of liability might have been different.…”