Abstract
Purpose
This brief report examines the impact of a defendant’s Autism Spectrum Disorder (ASD) diagnosis, as well as the influence of expert testimony and genetic evidence, on the perceptions, knowledge, and sentencing views of a sample of state court judges in the U.S.
Methods
Data were collected from sixty-one California Superior Court judges who responded to a survey featuring a structured case study about a defendant diagnosed with ASD. The survey assessed judges’ views on the influence of the defendant’s ASD diagnosis and its genetic etiological influences on sentencing, responsibility, and perceptions of the defendant’s behavior.
Results
Findings indicate that most judges believe that an ASD diagnosis and its genetic influences would influence their sentencing decisions, with almost all considering it a mitigating factor to sentencing, but that it did not substantially affect a defendant’s legal responsibility. Survey responses revealed significant gaps in judges’ knowledge about ASD, underscoring the need for enhanced judicial training.
Conclusion
Findings highlight the influence of ASD and behavioral genetic evidence on judicial views and potential decision-making in cases involving defendants with ASD, indicating a clear need for improved access to education and resources on the disorder. Addressing these educational gaps can help the criminal justice system better accommodate the complexities associated with scientific and ASD evidence, which may promote more equitable treatment for defendants with ASD.
From the article:
This preliminary survey data revealed significant insights into how a defendant’s ASD diagnosis affected judges’ views of different case-related factors. Overall, almost all judges reported that the diagnosis of ASD would be influential in their sentencing decision in the case. These findings suggest that many judges appear sympathetic and cognizant of the challenges associated with ASD in sentencing contexts, with the large majority of judges here indicating that they believe ASD should be viewed as a potential mitigating factor; this is consistent with findings from prior work (Berryessa, 2014b, Berryessa, 2016b). Most judges also reported that knowledge of the genetic etiological influences on a defendant’s ASD was, to some extent, influential in shaping their views on the case, which aligns with previous findings (Berryessa, 2016a).
Most judges viewed the defendant’s legal responsibility to be unaffected by his ASD, which also complements findings from Berryessa (2014b). Yet they also reported that the expert testimony on ASD particularly influenced their views on the defendant’s criminal intention. This suggests that judges may view a defendant as fully legally responsible for his behavior but, at the same time, also deeply question his understanding of his own intentions, actions, and decision-making abilities. This differentiation is consistent with judges’ professional training and their obligation to assess legal responsibility within statutory boundaries; rather than reflecting misunderstanding, the observed difference between moral and legal responsibility likely represents a nuanced awareness of how autism may influence culpability without diminishing legal accountability (Freckelton and List, 2009, Grant et al., 2018). This may suggest that judges may also be likely to view ASD as relevant to other stages of the legal process in which defendants must make decisions; aligned with other work, examining competency to stand trial may be especially relevant, as a defendant’s difficulties in understanding the intent of his own actions could also lead to challenges in comprehending the trial process and assisting in his defense (Brewer et al., 2016, Mayes, 2003). Although an ASD diagnosis alone typically does not meet the statutory criteria for insanity defenses in the United States, ASD-related evidence might be used by attorneys to contextualize behavior and argue for mitigation (Caliman and Berryessa, 2025a, Caliman and Berryessa, 2025b). This approach mirrors the broader defense strategies observed in recent qualitative work, where attorneys emphasize diminished moral culpability, communication challenges, or atypical reasoning patterns to seek leniency and appropriate accommodations for defendants with ASD (Caliman & Berryessa, 2025b).
Additionally, almost all judges reported that the expert testimony influenced their opinions of the case in some way, indicating a potential openness to different types of expert evidence in cases involving ASD (Berryessa, 2017). A small subset of judges, however, reported that the expert testimony did not alter their opinions, which might indicate prior familiarity with ASD or prior experience with defendants with ASD. The findings of this study offer valuable insights for expert witnesses, emphasizing aspects of cases involving ASD, such as criminal intention and dangerousness, that judges may believe are most affected by expert testimony. Similar patterns appear in jury research, where providing accurate information about ASD improves understanding of atypical behavior and leads to less punitive judgments (Baker et al., 2025, Berryessa et al., 2015, Brewer et al., 2016, Maras et al., 2019). These parallels suggest that both jurors and judges benefit from targeted psychoeducation to reduce stigma and support informed decision-making.
Results also revealed significant gaps in judges’ knowledge about ASD and behavioral genetics. Most judges rated their knowledge as slight to moderate, with very few judges rating it as high–aligning with previous work emphasizing the need for better judicial education on complex scientific topics (Berryessa, 2016b, Berryessa, 2019). Most judges expressed an interest in formal training in order to obtain forensic information about ASD and genetics, underscoring the need for comprehensive training programs and continuing education through conferences. By enhancing their knowledge, judges may improve their ability to critically evaluate expert testimony on ASD as well as genetic evidence, mitigating the risk of over-reliance on such evidence and preventing the misuse of unqualified testimony in judicial decision-making processes.
