A man steals candy from a baby. Whether or not the baby cries, most would argue that the man acted immorally. It seems that humans have an innate ability to judge if an act is moral or not, regardless of the act’s outcome or consequences.
How we judge whether actions are moral or not is a subject that some people attribute to human spirituality, while others simply chalk it up to the mysterious inner workings of the human mind. A study recently published in the Proceedings of the National Academy of Sciences by Dr. Liane Young and colleagues from the Massachusetts Institute of Technology may just bring us one step closer to understanding how the brain controls our moral judgments.
When judging the morality of another person’s actions, we usually analyze the person’s intent. For example, if the man who stole candy from the baby did so to protect the baby from a closely swarming bee, his actions might be considered permissible. This conclusion requires our ability to infer the mental state of another person. Dr. Young hypothesized that an area of the brain involved in mental state reasoning, called the right temporoparietal junction (RTPJ), would be required for making moral judgments.
To test this hypothesis, Young’s group disrupted the RTPJ using transcranial magnetic stimulation (TMS), a noninvasive technique that uses focused magnetic fields to disrupt neural activity in a specific area of the brain. Volunteers were then asked to make moral judgments about fictitious scenes.
The experiment included four scenarios. Each scenario consisted of either a neutral act or negative act combined with a neutral outcome or negative outcome. When the volunteers received TMS on a control area of the brain (in other words, the RTPJ was functioning), most of the participants indicated that a negative act was less permissive, whether or not the outcome was neutral or negative. However, when the RTPJ was disrupted, the volunteers indicated that the negative act was more permissible if the outcome was neutral.
This suggests that with the RTPJ disrupted the volunteers based their judgments on the outcome, rather than the act itself.
In the man and baby scenario, this study implies that a disrupted RTPJ would lead a person to conclude that stealing candy from a baby is permissible as long as the baby doesn’t cry.
The Bottom Line: The right temporoparietal junction of our brains helps correlate intentions and outcomes when making decisions about the permissiveness (morality) of another person’s activities.
So, cultural exposures aside, it’s interesting to think about friends who seem more comfortable with—what some might consider—immoral acts, as long as there isn’t a bad outcome…
Reference: Proc Natl Acad Sci U S A. 2010 Apr 13;107(15):6753-8.