Jessica Sommerville

Studying how infants perceive fairness and how that relates to their prosocial behaviors.

The ability to be ”fair” in a situation and the ability to evaluate other people's actions as “fair” are integral to successful societal functioning. Research suggests that adults across cultures have a preference for fair outcomes. For example, when given the opportunity to distribute a sum of money (e.g., $20) between oneself and another person in an experimental game, most adults choose an equal split of the money ($10 each).

In our research, we are exploring when children start to show preferences for fair outcomes, and how developments in children's appreciation of fairness may be related to prosocial behaviors, such as sharing and helping others. In a recent experiment, we tested 15-month-old infants using a task that investigated infants' responses to fair and unfair outcomes (Schmidt & Sommerville, in press). Infants watched a movie in which an actor distributed either crackers or milk to two recipients. The crackers or milk were either distributed in a fair manner (both actors got equal amounts), or an unfair manner (one actor got more than the other). How long infants looked at the fair and unfair outcome was measured. The longer infants look at an event is an indication of the event being viewed as unusual or unexpected. We found that infants looked longer at the unfair outcome than the fair outcome, suggesting they viewed the unfair outcome as unexpected.

In the same experiment, infants also took part in a sharing task, in which they could choose to share a preferred toy, an unpreferred toy, or to not share at all. Roughly 1/3 of infants shared the preferred toy, 1/3 shared the unpreferred toy, and 1/3 shared no toy at all, suggesting that there were differences in how infants choose to share at this age. We also found a close association between infants' sensitivity to unfair outcomes (how long they looked at the unfair event in the prior task) and their sharing behavior: infants who shared their preferred toy were most sensitive to the unfair outcome, whereas infants who shared their unpreferred toy did not appear to be as concerned with whether the movie outcome was fair or unfair.

Our findings suggest that the ability to evaluate social interactions according to whether they are fair or unfair emerges very early in life. In addition, there are differences in personal orientations toward fairness and sharing that are already present by the second year of life. In ongoing work, we are investigating whether these early individual differences pave the way for later differences in moral behavior and empathy, as well as how parental values, attitudes and beliefs shape the development of fairness and sharing over the first two years of life.