Changes in brain circuitry play role in moral sensitivity as people grow up

By William Harms
Researchers showed video clips that portrayed intentional and accidental harm, and found that all participants, irrespective of their age, paid more attention to people being harmed and to objects being damaged than they did to the perpetrators. Courtesy of Jean Decety

(Medical Xpress) -- People's moral responses to similar situations change as they age, according to a new study at the University of Chicago that combined brain scanning, eye-tracking and behavioral measures to understand how the brain responds to morally laden scenarios.

Both and adults distinguish between damage done either intentionally or accidently when assessing whether a had done something wrong. Nonetheless, adults are much less likely than children to think someone should be punished for damaging an object, especially if the action was accidental, said study author Jean Decety, the Irving B. Harris Professor in Psychology and Psychiatry at the University of Chicago and a leading scholar on affective and social neuroscience.

The different responses correlate with the various stages of development, Decety said, as the brain becomes better equipped to make reasoned judgments and integrate an understanding of the mental states of others with the outcome of their actions. alert people to the moral nature of a situation by bringing on discomfort that can precede , and such an is stronger in , he explained.

"This is the first study to examine brain and behavior relationships in response to moral and non-moral situations from a neurodevelopmental perspective," wrote Decety in the article, "The Contribution of Emotion and Cognition to Moral Sensitivity: A Neurodevelopmental Study," published in the journal . The study provides strong evidence that moral reasoning involves a complex integration between affective and that gradually changes with age.

For the research, Decety and colleagues studied 127 participants, aged 4 to 36, who were shown short video clips while undergoing an scan. The team also measured changes in the dilation of the people's pupils as they watched the clips.

The participants watched a total of 96 clips that portrayed intentional harm, such as someone being shoved, and accidental harm, such as someone being struck accidentally, such as a golf player swinging a club. The clips also showed intentional damage to objects, such as a person kicking a bicycle tire, and accidental damage, such as a person knocking a teapot off the shelf.

For their research, Prof. Jean Decety and his colleagues showed 127 participants, aged 4 to 36, short video clips while they underwent an functional MRI (fMRI) scan. Courtesy of Jean Decety

in the scanner revealed that all of the participants, irrespective of their age, paid more attention to people being harmed and to objects being damaged than they did to the perpetrators. Additionally, an analysis of pupil size showed that "pupil dilation was significantly greater for intentional actions than accidental actions, and this difference was constant across age, and correlated with activity in the amygdala and anterior cingulate cortex," Decety said.

The study revealed that the extent of activation in different areas of the brain as participants were exposed to the morally laden videos changed with age. For young children, the amygdala, which is associated the generation of emotional responses to a social situation, was much more activated than it was in adults.

In contrast, adults' responses were highest in the dorsolateral and ventromedial prefrontal cortex — areas of the brain that allow people to reflect on the values linked to outcomes and actions.

In addition to viewing the video clips, participants were asked to determine, for instance, how mean was the perpetrator, and how much punishment should he receive for causing damage or injury. The responses showed a clear connection between moral judgments and the activation the team had observed in the brain.

"Whereas young children had a tendency to consider all the perpetrator malicious, irrespective of intention and targets (people and objects), as participants aged, they perceived the perpetrator as clearly less mean when carrying out an accidental action, and even more so when the target was an object," Decety said.

When recommending punishments, adults were more likely to make allowances for actions that were accidental, he said. The response showed that they had a better developed prefrontal cortex and stronger functional connectivity between this region and the amygdala than children. Adults were better equipped to make moral judgments.

"In addition, the ratings of empathic sadness for the victim, which were strongest in young children, decreased gradually with age, and correlated with the activity in the insula and subgenual prefrontal cortex," which area areas associated with emotional behavior and automatic response to stresses, Decety said. Together, the results are consistent with the view that morality is instantiated by functionally integrating several distributed areas/networks.

Related Stories

Emotions key to judging others

Mar 24, 2010

Imagine this scenario: A woman and her friend are touring a chemical factory. They come to a coffee machine and, next to it, a container labeled “toxic.” The woman sees the label but goes ahead and scoops ...

Feelings matter less to teenagers

Sep 07, 2006

Teenagers take less account than adults of people’s feelings and, often, even fail to think about their own, according to a UCL neuroscientist. The results, presented at the BA Festival of Science today, show that teenagers ...

Sleep deprivation affects moral judgment

Mar 01, 2007

Research has shown that bad sleep can adversely affect a person's physical health and emotional well-being. However, the amount of sleep one gets can also influence his or her decision-making. A study published in the March ...

Recommended for you

Xenon exposure shown to erase traumatic memories

17 hours ago

McLean Hospital researchers are reporting that xenon gas, used in humans for anesthesia and diagnostic imaging, has the potential to be a treatment for post-traumatic stress disorder (PTSD) and other memory-related disorders.

Stop and listen: Study shows how movement affects hearing

17 hours ago

When we want to listen carefully to someone, the first thing we do is stop talking. The second thing we do is stop moving altogether. This strategy helps us hear better by preventing unwanted sounds generated ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

David_Wishengrad
2.3 / 5 (3) May 28, 2011
They missed something very important, the effects of the surrounding environment. Man is not supposed to eat flesh, as his genetically current natural diet is fruit and plants. The only way this test can really produce usable data is for special applied attention to babies raised to adulthood, as complete vegetarians, as baseline control set. If scientists want to do research science on people, lets get the all facts straight that we already know, and use them. Maybe they will do better the next time.
cmn
1 / 5 (1) May 28, 2011
Can I buy pot from you, David?
KBK
3 / 5 (2) May 28, 2011
They missed something very important, the effects of the surrounding environment. Man is not supposed to eat flesh, as his genetically current natural diet is fruit and plants. The only way this test can really produce usable data is for special applied attention to babies raised to adulthood, as complete vegetarians, as baseline control set. If scientists want to do research science on people, lets get the all facts straight that we already know, and use them. Maybe they will do better the next time.


Absolutely correct.

There have been recent studies that have noted how the bacteria in the gut changes with diet and that the gut bacteria denotes the psychological outlook and behavior of the given person.

no guff, no bull. look it up. Just like you were told once by wise people: You are what you eat.

David_Wishengrad
not rated yet May 28, 2011
Thanks KBK :) I read that article too. Here it is: http://medicalxpr...gut.html We are getting there ...