Reliance on emotion fades as we age

U. CHICAGO (US) — Children have more empathy for victims, judge wrongdoing more harshly, and are more likely to believe in punishment for damage done.

The different responses correlate with various stages of development as the brain becomes better equipped to make reasoned judgments and understand the mental states of others with outcomes of actions, says Jean Decety, professor of psychology and psychiatry at the University of Chicago.

Negative emotions alert people to the moral nature of a situation by bringing on discomfort that can precede moral judgment, an emotional response that is stronger in young children.

“This is the first study to examine brain and behavior relationships in response to moral and non-moral situations from a neurodevelopmental perspective,” writes Decety in the study, published in the journal Cerebral Cortex.

Truth lies in the eyes

For the research, 127 participants age 4 to 36 were shown short video clips while undergoing an fMRI scan. Researchers measured changes in the dilation of the people’s pupils as they watched the clips.

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. 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 a shelf.

Eye tracking in the scanner revealed that all of the participants, no matter what age, paid more attention to people being harmed and to objects being damaged than they did to the perpetrators. Pupil dilation was also significantly greater across the board for intentional actions than accidental actions.

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 with 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.

Participants were asked to determine how mean the perpetrator was, 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 perpetrators 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 says.

When recommending punishments, adults were more likely to make allowances for actions that were accidental. The response shows they have 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.

“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 are areas associated with emotional behavior and automatic response to stresses.

“Together, the results are consistent with the view that morality is instantiated by functionally integrating several distributed areas/networks.

The research was supported with a grant from the National Science Foundation.

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