Neuroimages as evidence in a mens rea defense: No impact.

Abstract

Recent developments in the neuropsychology of criminal behavior have given rise to concerns that neuroimaging evidence (such as MRI and functional MRI [fMRI] images) could unduly influence jurors. Across four experiments, a nationally representative sample of 1,476 jury-eligible participants evaluated written summaries of criminal cases in which expert testimony was presented in support of a mental disorder as exculpatory. The evidence varied in the extent to which it presented neuroscientific explanations and neuroimages in support of the expert's conclusion. Despite suggestive findings from previous research, we found no evidence that neuroimagery affected jurors' judgments (verdicts, sentence recommendations, judgments of the defendant's culpability) over and above verbal neuroscience-based testimony. A meta-analysis of our four experiments confirmed these findings. In addition, we found that neuroscientific evidence was more effective than clinical psychological evidence in persuading jurors that the defendant's disorder reduced his capacity to control his actions, although this effect did not translate into differences in verdicts.

Neuroimage Evidence and the Insanity Defense

“…Any increased persuasiveness of neuroscience expert evidence appears to be contained in the overall message, whether or not accompanied by a brain image. Combined with earlier experiments finding no added impact of brain images in simulated criminal cases (Schweitzer et al, 2011), these results suggest that the more intriguing question is why brain images are not as compelling to laypersons as they seem to be to neuro-and other scientists. The answer might be that by virtue of their unfamiliarity and perhaps alien quality, brain images have far less meaning to laypersons.…”

“…In a previous set of experiments (Schweitzer et al, 2011), we examined the influence of neuroimagery on jurors' verdicts and sentencing recommendations when the neuroevidence was offered in support of a mens rea defense. In our first of four experiments, we asked a nationally representative sample of mock jurors to evaluate a written summary of a robbery/homicide case in which the defense raised the argument that, due to severe mental problems, the defendant could not have formed the intent required under the law to be guilty of murder.…”

“…We accomplish these goals using methods similar to those employed in Schweitzer et al (2011). Using a diverse sample of community participants from throughout the United States, we presented a written mock criminal trial in which the defense offered expert evidence in support of an NGRI plea.…”

Memory and law: what can cognitive neuroscience contribute?

“…When accompanied by brain scans, the lie detection evidence produces more guilty verdicts than when accompanied by other evidence such as polygraph or thermal facial imaging 57 . Although effects of brain scans on juror decision making are not always observed 58 , it is nonetheless noteworthy that in a recent murder case in which the defense sought to introduce fMRI evidence from a lie detection procedure to substantiate their claims that the defendant was telling the truth, the court did not allow the evidence after hearing expert testimony from both sides 59 .…”

Judging mechanistic neuroscience: a preliminary conceptual-analytic framework for evaluating scientific evidence in the courtroom

“…Although recent empirical work suggests that the admission of neuroscientific evidence in the courtroom has not yet impacted legal decision-making to a significant degree (For example Schweitzer, Saks, Murphy, Roskies, Sinnott-Armstrong, & Gaudet, 2011;Morse, 2017), it is important to note that much of the evidence that has been Preprint Forthcoming in Psychology, Crime and Law admitted to date has been correlational rather than causal-mechanical. Until fairly recently, details about causal pathways linking brain abnormalities to observable behavior have been missing.…”