I’m writing this while my kids are playing in an indoor playground. They just had a small fight about the last cookie my youngest son took. New research shows he probably can’t help it as it suggests that age-associated improvements in the ability to consider the preferences of others are linked with maturation of a brain region involved in self control. The findings may help to explain why young children often struggle to control selfish impulses, even when they know better.

From the press release:

Human social interactions often involve two parties who want to maximize their own outcomes while reaching a mutually satisfactory result. It is generally accepted that over the course of childhood behavior shifts from a more selfish focus to an increased tendency to consider the benefits to others. However, little is known about age-related changes in this type of “strategic social behavior” or the underlying neuronal mechanisms.

Researchers from the Max-Planck Institute for Cognitive and Brain Sciences in Leipzig conducted behavioral and brain-imaging studies comparing children of different ages as they engaged in two carefully constructed games called “The Dictator Game” and “The Ultimatum Game.” In the Dictator Game, children were asked to share a reward with another child who could only passively accept what was offered. In the Ultimatum Game, the recipient had to accept the offer or neither child received a reward. Therefore, the games differed in the demand for strategic behavior for the child making the offer.

“We were interested in whether children would share more fairly if their counterparts could reject their offers, and to what extent strategic behavior was dependent on age and brain development,” explains lead study author, Dr. Nikolaus Steinbeis. “We observed an age-related increase in strategic decision making between ages 6 to 13 years and showed that changes in bargaining behavior were best accounted for by age-related differences in impulse-control abilities and underlying functional activity of the left dorsolateral prefrontal cortex, a late-maturing brain region linked with self control,” explains Dr. Steinbeis.

The results suggest that egocentric behavior in children may not be a function of an inability to know “fair” from “unfair,” but is instead due to an immature prefrontal cortex that does not support altruistic behavior when faced with a situation that has a strong self-serving incentive. “Our findings represent a critical advance in our understanding of the development of social behavior with far-reaching implications for educational policy and highlight the importance of helping children act on what they already know,” concludes Dr. Steinbeis. “Such interventions could set the foundation for increased altruism in the future.”

Abstract of the study:

Human social exchange is often characterized by conflicts of interest requiring strategic behavior for their resolution. To investigate the development of the cognitive and neural mechanisms underlying strategic behavior, we studied children’s decisions while they played two types of economic exchange games with differing demands of strategic behavior. We show an increase of strategic behavior with age, which could not be explained by age-related changes in social preferences but instead by developmental differences in impulsivity and associated brain functions of the left dorsolateral prefrontal cortex (DLPFC). Furthermore, observed differences in cortical thickness of lDLPFC were predictive of differences in impulsivity and strategic behavior irrespective of age. We conclude that egoistic behavior in younger children is not caused by a lack of understanding right or wrong, but by the inability to implement behavioral control when tempted to act selfishly; a function relying on brain regions maturing only late in ontogeny.