Science Watch

Newborns have quite a reputation to uphold: They're notorious eating, sleeping, diaper-dirtying machines. Often dismissed as "blank slates," they have much to learn.

Yet they also have plenty to teach us. As scientists explore what's going on in those adorably tiny heads, they're finding that babies have a surprisingly rich understanding of the social worlds around them.

"People used to think that infants' cognitive abilities were severely limited," says Jessica Sommerville, PhD, a psychologist at the University of Washington. "But more recent tools and research have really painted an entirely different picture."

For most of the 20th century, developmental psychology textbooks taught that it took years for kids to grasp such social-moral concepts as fairness and altruism. Those studies, though, had a serious limitation: They relied primarily on interviews with children and thus could reveal nothing about pre-verbal infants or toddlers with a limited lexicon.

A turning point came in the 1980s when Renee Baillargeon, PhD, director of the Infant Cognition Laboratory at the University of Illinois at Urbana-Champaign, and colleagues developed a method to test what babies understood about objects and events in the environment around them. The technique is based on their finding that babies look measurably longer at events that defy their expectations.

The team and others have since explored what infants understand about the mental states of others, a concept known as "theory of mind." More recently, that work has led to questions about social and moral development in infants and young children, says Karen Wynn, PhD, who directs the Infant Cognition Center at Yale University. "The research landscape is continually changing as science starts to ask questions that weren't actually asked of young babies before."

Helping hands

Studying morality in infants is sticky. Morality is hard to define, even among adults. Still, researchers in this field have focused on a few key traits, including helpfulness, fairness and kindness. These "prosocial behaviors," research indicates, may be detectable in babies just a few months old.

In one such study, Wynn and colleagues J. Kiley Hamlin, PhD, and Paul Bloom, PhD, showed 3-month-old infants a googly-eyed circle puppet trudging up a hill. In one scenario, a helpful triangle helped push the circle upward. In another, a not-so-nice square knocked the circle back to the bottom of the hill. Later, an experimenter showed both characters to the babies. The infants preferred to gaze at the helpers over the hinderers. That preference seemed to exist only in a social context, since the babies didn't show any preference when the cartoon shapes pushed inanimate objects up or down the hill (Developmental Science, 2010). By 5 months old, after they've mastered more motor skills, babies actively reach toward the nice character over the mean one — suggesting that the 3-month-olds' extended gaze is in this case an indication of their preference. The findings suggest that babies can distinguish between good guys and bad guys before they can even roll over.

By the time they turn 1, babies have the physical skills to start engaging in helpful behaviors themselves — and a number of studies have shown that they do so eagerly. In fact, they help even without being asked and without being praised or rewarded for the effort, says Felix Warneken, PhD, a psychologist at Harvard University.

Warneken and Michael Tomasello, PhD, of the Max Planck Institute for Evolutionary Anthropology in Germany, gave 2-year-olds an opportunity to help an unfamiliar adult pick up dropped objects such as markers and paperclips. The researchers found that children helped equally and often, whether their parents pointed out the problem, encouraged them to help, ordered them to do so or just stood quietly nearby. It didn't even matter if the parents were in the room. These results suggest that toddlers have an intrinsic desire to be helpful, Warneken says (Infancy, 2013).

But babies also seem to understand that not everyone deserves to be helped. Valerie Kuhlmeier, PhD, head of the Infant Cognition Group at Queen's University in Ontario, and Kristen Dunfield, PhD, now at Concordia University in Montreal, presented 21-month-olds with two scenarios. In one, an adult teased the baby with a toy but wouldn't share it. In the other, a second adult tried to share a toy with the child but was unable to hand it over because of the way the room was set up. Then, when an experimenter dropped a toy out of reach of the adults, the babies were more likely to give it to the person who had earlier tried to share (Psychological Science, 2010).

"Even at 21 months, the babies could read the intention; it was the thought that counts," Kuhlmeier says. "Prosocial behavior is costly, and it may make sense to engage in those behaviors selectively."

Fair and square

Any parent who has heard a child shrieking, "It's not fair!" knows that kids are sensitive to inequality. But babies understand the concept of fairness long before they have the words to whine about it, recent research shows.

In one study by Baillargeon and colleagues, for example, babies stared longer at cookies divvied up unequally between two animated giraffe puppets than cookies handed out in even rations. That is, the babies seemed to expect equality and were surprised if one puppet got shortchanged. However, that expectation only held for animate creatures. When the experimenter divided the cookies between inactive stuffed giraffes, the babies looked equally long whether the cookies were divided evenly or not (Psychological Science, 2012).

In a second component of that study, babies watched as an experimenter gave stickers to two women. In some cases, both women had previously helped put away toys. In others, one had done all the work while the other played. Baillargeon and colleagues found that 21-month-olds were surprised when the slacker got a sticker — but only if the experimenter could see who had worked and who hadn't. Before their second birthday, babies seem to understand that you have to earn your fair share, the study suggests.

A sense of fairness seems to be so strong by age 3 that kids are willing to forgo a reward altogether if they think they're being treated unjustly, another study finds. Peter R. Blake, EdD, and Katherine McAuliffe, PhD, devised a contraption that distributed Skittles to dishes in front of two children. When given the choice to deliver more candies to the other child or none to either, 4-year-olds often opt to trash all the sweets (PLOS ONE, 2013). "They'd rather have none than one" if another child is poised to get more, says Warneken, a study co-author.

Just because children understand fairness, though, doesn't mean they practice it. In a pair of studies, Blake and McAuliffe showed that most 4- to 7-year-olds rejected situations in which they'd receive a smaller share of candy or stickers, but accepted inequality if they were in line to get the larger pile — even when they said sharing was the right thing to do. "Children seem to endorse equality, but they don't always use it," Warneken says. That thinking seems to shift at around age 7 or 8, the researchers found (Cognition, 2011; PLOS ONE, 2013).

Before then, kids actually seem to prefer an unfair situation when it gives them the upper hand. Wynn and colleagues gave 5-year-olds a chance to choose a pile of tokens they could trade in for a prize. They found kids preferred to take seven tokens if another child would get none, rather than eight tokens for both (Cognition, 2014).

"Young kids are actually extremely self-interested and are in fact angling positively towards basic unfairness," says Wynn. "When put together with the infant findings, this highlights an important distinction between what babies and kids want others to do, and what they want for themselves."

Inclined to be kind?

Other research by Sommerville suggests that fairness and generosity are intertwined from as early as age 1. In an experiment similar to Baillargeon's giraffe study, she found that 15-month-olds who were most surprised by an unfair cracker quota were more likely to share their favored toy (PLOS ONE, 2011).

Because other research indicates that recognition of fairness emerges between 9 months and 12 months of age, Sommerville says the 15-month-olds who were less sensitive to injustice probably weren't just lagging behind their peers on that developmental milestone. "We actually think that we are starting to tap into some of the individual differences that will persist over time," she says.

Individual differences aside, certain social situations may inspire a person to act more or less morally. Warneken and his colleagues demonstrated this idea in an experiment designed to test fairness in action.

The researchers rigged a system in which two kids had to work together to pull a rope to lift a box with marbles inside. Starting around age 3, they found, the children were inclined to share the marbles if they had worked together to retrieve them. If one child ended up with three marbles while her partner got just one, she'd share so that they each had two. However, if the kids worked side-by-side independently to get the marbles, they weren't bothered if they each ended up with a different number in the end.

In that regard, 3-year-olds are a step ahead of our primate cousins. Warneken and his colleagues ran the same experiment with chimpanzees, and found that the apes were willing to team up to retrieve food rewards. But if one chimp ended up with more snacks than its partner, it happily kept them all (Nature, 2012). An early sense of fairness may have evolved to help humans work together to survive, Warneken suggests. "Collaborative work is the cradle of equality," he says.

One of us

Evidence is also mounting that babies understand the concept of "us" versus "them" from an early age.

In one example, Wynn, Hamlin and colleagues asked 9-month-old and 14-month-old babies to choose a food, either graham crackers or green beans. Then the babies watched a series of puppet shows in which one puppet liked crackers and the other preferred green beans. Infants in both age groups preferred characters who were nice to the puppet that shared their tastes.

That was in line with previous findings and not unexpected. But the next finding surprised the researchers: The babies also had a clear preference for characters who were mean to the dissimilar puppet (Psychological Science, 2013).

Wynn is hesitant to describe her findings in the psychological lingo of "in-groups" and "out-groups" since it's unclear whether babies are constructing social groups around these shared food preferences. "It seems to be fundamentally about a shared preference: You value aspects of the world the same way I do, so I like you," she says.

Other studies suggest that while babies recognize social groups, they don't necessarily expect prejudice toward people outside the group. Baillargeon has run studies in which experimenters identify themselves as members of made-up social groups by announcing, for instance, "I am a lumi" or "I am a tarfen." She's found that 16-month-old babies are surprised when a person fails to help another member of his or her group. However, the babies in her studies seem to have no expectations about whether a person should help an outsider, she says. "If they aren't part of your club, you have a choice in whether or not to get involved."

As scientists continue to study infants' social and moral development, one big question remains unanswered: Are social-moral principles learned, or are babies born with these systems already in place?

One important clue may come from cross-cultural studies, which can help illuminate how and when babies from different cultures exhibit various social behaviors, researchers say. But such studies just haven't been done yet.

"Studying babies is pure, in a way. It can tell us how our social and moral processes develop before they're muddied up by culture or language or complex reasoning," Baillargeon says. "When you look at babies, it's magical."

Kirsten Weir is a journalist in Minneapolis.