Jury research is just not that impressive. Studies done by psychologists and others in the social sciences often rely on convenience samples of college students, sample sizes are often quite small, but most importantly? Juries just aren’t nearly as relevant as you might think. When the majority (read: 90-95%) of criminal cases are plea-bargained, it’s hard to get all worked up about what potential juror members might think.
Take this recent study, for example. 26 study subjects participated in a study that involved reading different crime scenarios and then scanning their brains to look for brain activity linked to either leniency or punitiveness. It’s already a ridiculously small sample size, but then, as the article says, “Readings from three of the subjects were not included in the analysis because they moved excessively during the brain scans, and one subject fell asleep during the experiment. That left 22 people in the study.”
So now we’re looking at just 22 people. As the researchers describe them, they are “(11 males; mean age=21.5±1.9 (s.d.) years).” In other words, they are young, most likely college-aged. Without knowing more about the subjects or the recruiting strategies, I still feel pretty comfortable going out on a limb and saying that it’s not very likely they are generalizable to real jury members.
Add in the fact that this is a Japanese study, and we’re now even further from being able to draw conclusions about implications for the American criminal justice system given that Japanese norms on crime and punishment are likely to differ in important ways.
Despite all of these problems, the study authors don’t hesitate to overstate the importance of their work in the article published by Nature. Yamada et al write, “These results could help the legal system understand how potential jurors actually decide, and contribute to growing knowledge about whether emotion and cognition are integrated sensibly in difficult judgments.”
I disagree. This study gives us nothing important in understanding criminal justice systems. Thanks to CSI, there are now far too many people laboring under the false notion that if you stick science-y stuff with criminal justice-y stuff, you come up with something that is sexy, valuable, and real.
This brain research probably has some value. Just not in the context of juries.