Babies Form Taste-Based Alliances from as Early as Nine Months

When we look for the causes of prejudice in society and, most of us take it for granted that prejudice is taught, not learned. But you don’t have to have grown up with overtly bigoted parents to have acquired some prejudices in much subtler ways. And as a study released today in the journal Psychological Science tells us, we start picking up on those subtle social cues at a very young age.

Led by psychological scientist Kiley Hamlin while she was a graduate student at Yale (she’s now a professor at the University of British Columbia), a team of researchers designed a simple test for infants that showed they begin to show a preference for individuals who are nice to people who are “like them” and mean to people who are not.

To do this, the researchers designed a simple test in which infants of nine and 14 months were directed to choose between graham crackers and green beans. The infants were then given a puppet show, in which one bunny chose graham crackers and another bunny chose green beans. Past research shows we’re drawn to people who like the same things we do. So the infants were expected to identify on some level with which ever bunny showed the same preference they did.

In another series of puppet shows, experimenters introduced another two puppets: a helper or “nice” dog and a harmer or “mean” dog. In situations where the two original puppets—those who chose between green beans and graham crackers—dropped a ball they were playing with, the “helper” puppet always gave the ball back. See below:

In scenes with the “harmer” puppet, that puppet always stole the ball away.

When asked to choose, researchers expected the infants to be drawn to the dog that was nice to the bunny that had expressed the same preferences they had. But the infants also showed a distinct preference for the dog that was mean to the bunny that chose differently. That’s what we’re seeing below.

The researchers ran another experiment to test the latter finding, using a neutral puppet that hadn’t been used in a food preference test or a helping / harming test. The fourteen-month-olds preferred the dog that harmed the bunny who chose differently than they did, and, what’s more, preferred the neutral puppet to the dog that helped that bunny.

The nine-month-olds didn’t show the same preferences, leading the researchers to believe that those few months were a significant time in a child’s social development.

“The fact that infants show these social biases before they can even speak suggests that the biases aren’t solely the result of experiencing a divided social world, but are based in part on basic aspects of human social evaluation,” Hamlin said in a press release from the Association for Psychological Science, which publishes Psychological Science.

“Infants might experience something like schadenfreude at the suffering of an individual they dislike,” she added. “Or perhaps they recognize the alliances that are implied by social interactions, identifying an ‘enemy of their enemy’ (i.e., the harmer of a dissimilar puppet) as their friend.”

Forming such alliances from a young age clearly has its advantages. In human society, as in nature, some people want to help us and others want to hurt us. It makes sense to ally ourselves with people who help those who are like us, because the people like us are in our “tribe” so to speak. They’re our family, our friends, our role models. Conversely, if you’ve expressed a clear menace to someone like me—as the mean dog explicitly did—there’s at least some logic in believing there’s a chance you might do the same to me.

What’s frightening, of course, is imagining all the subtle ways our prejudices might be absorbed by the infants who look to us for all their cues. In the real world, an insignificant indicator of taste like the preference for graham crackers over green beans isn’t much of a basis for choosing one’s tribe. And yet the implied antipathy expressed by infants on such a trivial basis is consistent.

That doesn't simply mean that my imaginary baby wouldn't like you because you don't think Daydream Nation is the greatest album of all time (and my baby wouldn't, because it is). Other recent research shows that nine-month-old babies already identify better emotionally with people from the same racial group. Taken together and extrapolated over time, one can see how harmful prejudices develop over time.

The good news for those of us who try to correct prejudice where we see it, is that perhaps this reminds us how careful we need to around children who can’t even speak yet. They don’t know what you’re saying yet. But they’re watching the way you say it.