One night, Mark withdraws $200 cash from an ATM. He is on his way to meet his family, and intends to treat everyone to a special dinner at his favorite restaurant for his wife’s birthday. Just as he finishes his transaction, Dan rounds the street corner, pulls out a knife, and threatens Mark to hand over the cash. Mark, without hesitation, hands over the money, but Dan stabs him in the stomach anyway. Dan runs off, leaving Mark injured on the sidewalk.
How much should Dan be punished for this crime? There are many factors to weigh when coming to such a decision. Traditionally, in deciding on punishment, humans take into account the intent of the crime (for example, intentional versus accidental), as well as the level of harm caused (or intended to cause). For example, it appears that Dan’s intent was to steal Mark’s money, and hurt Mark in the process. The criminal act does not seem accidental. Additionally, Dan caused two types of harm. He stole Mark’s property, as well as causing physical bodily harm to Mark.
What brain areas are involved in weighing these factors and determining a punishment? For third-party punishment (where an uninvolved third-party, for example a judge, assigns punishment), the right dorsolateral prefrontal cortex, a region involved in moral decision-making (Greene, Sommerville, Nystrom, Darley, & Cohen, 2001), is more active when determining the extent of criminal responsibility for intentional crimes as opposed to accidental crimes (Buckholtz et al., 2008). This neural region is also activated during second-party punishment (where one involved party punishes another involved party) when participants are deciding whether to punish or not (Sanfey, Rilling, Aronson, Nystrom, & Cohen, 2003). In fact, when activity in this neural region is disrupted, the ability to punish economic norm violations is impaired in second-party punishment situations (Knoch et al., 2006; van’t Wout, Kahn, Sanfey, & Aleman, 2005). Overall, it appears that this region is involved in the decision to punish violations of social norms, and is dependent on blameworthiness of the perpetrator.
When determining how much punishment the perpetrator deserves, parts of the brain that are associated with emotional processing are activated, such as the A collection of nuclei found in the temporal lobe. The amygd..., medial prefrontal and posterior cingulate cortex. In fact, the higher the punishment, the more activity there is in these regions. This indicates that many regions of the brain are involved in this complex punishment decision-making process.
But trials include large amounts of other information about the perpetrator that influence courtroom decisions. For example, from the scenario above, what if it was revealed that Dan had a mental disability? One study (Yamada et al., 2012) found that sympathy for guilty perpetrators activated neural regions associated with mentalizing and moral conflict, including dorsomedial prefrontal cortex, precuneus and temporo-parietal junction.
In summary, there appears to be a network of brain regions, involving both executive control, as well as emotional, regions that work in an integrated way to make nuanced decisions about punishment.
Written by Mona Sobhani.
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Yamada M., Saori Fujie, Motoichiro Kato, Tetsuya Matsuda, Harumasa Takano, Hiroshi Ito, Tetsuya Suhara & Hidehiko Takahashi (2012). Neural circuits in the brain that are activated when mitigating criminal sentences, Nature Communications, 3 759. DOI: http://dx.doi.org/10.1038/ncomms1757