Even if toddlers can’t tell us, they are making hard and fast judgments about adults

See the column on the Wall Street Journal site

Adults often make snap judgments about babies. First impressions lead us to assign them personalities, such as fearful, active or easy to please, and with good reason. Fifty years of evidence shows that babies begin life with traits that set the stage for how they interact with the world—and how the world reacts to them.

That might be one reason why siblings can have such wildly different takes on their own families. Once a mother has assessed her child as shy or fussy, she tends to tailor her behavior to that baby’s personality.

But what if babies make hard and fast judgments about us, too? Just because they can’t say much doesn’t mean they don’t have strong opinions. New research shows that babies are astute observers of the emotional tenor of adult interactions and censor their own behavior accordingly. Published in the March issue of Developmental Psychology, the study shows that infants who get a glimpse of a stranger involved in an angry exchange with another stranger will then act more tentatively during play.

The study’s lead authors, Betty Repacholi and Andrew Meltzoff, both of the University of Washington, explained that infants who witness an emotional outburst then expect that person to lose his cool again in a new situation. “Babies are registering how we respond emotionally,” Dr. Meltzoff said, “taking notes on how we typically react.”

The experiment included 270 15-month-old toddlers who watched two adults unfamiliar to them demonstrating how to play with an intriguing new toy. One adult, called “the emoter,” reacted either neutrally or angrily to the other adult’s attempts to play with the toy, showing her emotional cards by commenting “that’s entertaining” in a dispassionate tone or “that’s aggravating” in an angry rebuke.

The babies who witnessed the adult’s harsh reaction were then more likely to hang back before touching the intriguing toy. Even if the anger-prone adult had turned her back, and even when a different plaything was offered, the child’s hesitation was palpable. Some toddlers avoided the toy altogether.

Taking an adult’s emotional temperature happened quickly. Each baby was tested three times, but it usually took just one instance of verbal aggression for the baby to pigeonhole an adult as a hothead. The babies had “formed an impression about [the adult’s] psychological makeup, that this is an angry person,” said Dr. Repacholi.

What’s more, a secondhand brush with a riled-up adult will prompt toddlers to mollify that person. Other studies by Drs. Repacholi and Meltzoff and colleagues, using the same “eavesdropping on two strangers” design and published in February in the journal Infancy, showed that toddlers who witness an adult’s anger are more likely than other toddlers to hand over a prized toy. “Because they’ve learned that the adult is anger-prone, they try to appease her,” Dr. Repacholi said.

Well before they attribute thoughts and motivations to other people, young toddlers suss out any volatility in the adults around them, these studies show. But the findings also prompt some deeper questions. If brief shows of anger put toddlers on high alert, what might this mean for the inevitable conflicts that occur in family life?

As their studies involved babies observing the interactions between two people they had never met before, Drs. Repacholi and Meltzoff explained, their findings don’t really reproduce family life, during which parents and siblings show all kinds of feelings in various situations. “They have a history of interacting with their babies that the strangers in our study did not have,” Dr. Meltzoff wrote in an email.

Getting angry occasionally is not going to override the positive expectations that babies have built up about you over months of loving encounters, he told me. Still, “we are catching a glimpse of how babies pigeonhole us, and how they would describe our personalities, if they could only talk.”