For Babies, It's Better To Like What I Like

Babies as young as nine months appear to approve of people who like what they like — and approve of being mean to those who don't share their tastes. Kiley Hamlin, lead author of a study in the journal Psychological Science, discusses the importance of similarity to young children.

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This is SCIENCE FRIDAY. I'm John Dankosky. Ira Flatow is away. Later this hour, a look at the history, the engineering, the technology of Grand Central Terminal. It's 100 this year. But first, when you think about infants, those little angelic faces, some say they just love everyone. They don't know how to be mean. They don't dislike anybody.

But some of us have a different experience, meaning a baby who just does not like you for some reason, I just assumed it was because of my beard. Researchers are trying to sort out how these personal preferences work and how early they're developed.

A recent paper published in the journal Psychological Sciences finds that kids as young as nine months can have a bit of a mean streak, actually approving when someone is mean to a character they see as different somehow. That's what we're talking about first today. Give us a call. Our number is 1-800-989-8255. That's 1-800-989-TALK. If you're on Twitter, you can tweet us your questions by writing the @ sign, followed by scifri.

If you'd like more information about what we're talking about this hour, go to our website You will find links to our topic. First let me introduce our guest. Kiley Hamlin is a Canada research chair and an assistant professor of psychology at the University of British Columbia in Vancouver, Canada. Welcome to the program.

KILEY HAMLIN: Thanks for having me.

DANKOSKY: First of all, walk us through the study. What exactly did you do with these babies?

HAMLIN: Well, so we brought them into the lab, and we asked them what their food preference was. So we gave babies a choice between graham crackers and green beans. This allowed us to set up a puppet who was a similar - you know, had a similar food preference. So this puppet, say, also preferred graham crackers if the baby did.

And we showed them another puppet who expressed the opposite preference. So if the baby preferred graham crackers, this puppet preferred green beans. And then, basically, in previous studies, my colleagues Neha Mahajan and Karen Wynn had discovered that infants prefer the puppet who shares their preference.

We wanted to know whether their dislike for the puppet who didn't share their preference was strong enough or sort of, you know, if they disliked him enough in order to think differently about somebody who's nice to that individual versus mean to that individual.

Previous studies have shown that infants actually very much prefer nice puppets to mean puppets when they don't know anything about the target of a behavior. In this case we presented infants with a target that they knew and either liked because it shared their food preference or potentially disliked because it didn't share their preference.

DANKOSKY: OK so infants liked people who helped those that shared their preferences. That seems to make sense, right.

HAMLIN: Right.

DANKOSKY: They also liked those that hurt those who disagreed with their tastes in food. Did this surprise you at all?

HAMLIN: It did, yeah. We were expecting that maybe we could show some evidence that, you know, this made things a bit harder for them. You know, it's like well, I usually like niceness, but this guy's not my favorite, and so maybe those two motivations were going to compete, and we might find that babies got confused or something like that.

And fortunately or unfortunately, they weren't confused at all. Just as many babies who saw puppets being nice and mean to the dissimilar puppet who didn't share their preference, liked the mean one as the babies who saw puppets being nice and mean to the similar puppet liked the nice one.

So the idea is that they were just as strongly preferring the mean character as they did to a nice one, in a case of this, you know, the target being dissimilar to them.

DANKOSKY: OK, so a lot of parents are listening to this right now going, OK, you used graham crackers and green beans. Kids don't like green beans; kids love graham crackers. Did you control for this at all?


HAMLIN: Yes, of course. So critically in our study we went with what the baby liked. So all the babies chose between graham crackers and green beans, but surprisingly enough, close to 40 percent of infants actually chose green beans. So not only did not every baby like graham crackers, those babies who liked green beans showed exactly the same effects. So they liked the one who was mean to the puppet who liked graham crackers if that was opposite to their preference.

DANKOSKY: You've learned something else important, that babies like green beans, which is...

HAMLIN: I know.

DANKOSKY: Well, food preferences, though, seems like frankly a pretty minor thing to base this on. Do you think that this applies to bigger differences that people have?

HAMLIN: Well, so, you know, it's hard to know exactly what food preferences - of course, I don't tend to go around hating someone for liking, you know, a different kind of food than I like. On the other hand, we're constantly judging others for other kinds of preferences, so which sports team you like, which political party you root for and also just things like, you know, I tend to like swimming, and you like soccer, and so I might hang out with other kids who like swimming, things like that.

So certainly this case might be a very mild one, one that as adults we certainly don't think is worthy of this kind of process, we don't think it's OK to like those who harm those who just simply dislike our food. But on the other hand, there's lots of cases in which we do this kind of thing for bigger and more important opinions like politics or religion or, you know, sports affiliations.

DANKOSKY: Politics, religion, those are big ones. But what about race? That's of course a very important one. You look at someone, you say he doesn't look like me. So are babies thinking about race in this way?

HAMLIN: Yeah, so that's a great question, and actually I think that the answer is no. Katie Kinzler at the University of Chicago has some very lovely work showing that there are some things that infants seem to care a lot about, in particular what language somebody speaks. Infants actually seem very sensitive to that.

Our study suggests that they care about food preference. And in addition, her study suggests that they don't care about race. So they don't - they wouldn't rather take a toy from somebody of their own race. Very young children don't report they'd rather play with somebody of their own race, this kind of stuff.

So, even though adults seem to have race biases, infants don't really seem to, which is interesting. So we're showing that they're judging others for some things, things as simple as food preferences, but not for race. And so perhaps the sort of look judgments, judgments of how people look, is just not something that infants are doing as readily as adults are, which is pretty interesting.

DANKOSKY: What about gender? Because that's sort of in the middle there. That's important, and there are differences. Does gender get picked up?

HAMLIN: Gender is one of the most salient social categories to, you know, humans of all ages, absolutely. It's interesting with gender because unlike things like race or food preference or things like that, the division of gender categories is so prevalent. You know, it's completely fine for a preschool teacher to say OK, boys and girls, you know, let's start, whereas no teacher would say OK graham cracker and green bean lovers, you know, let's start class today.

So basically gender is something that yes, is incredibly picked up on, and I imagine that if we could design the study in the right way we might show these effects. Kids definitely want to be friends with kids of their own gender.

On the other hand, we're socializing that to a much greater extent than even the other things that we know, the biases that we know humans do show. And so it's hard to tease apart the role of socialization versus just sort of a basic social process in that particular realm.

DANKOSKY: You've already said when kids don't show a strong preference one way or the other, they're going to tend to like the nice puppet, someone who does something well. But as humans, a lot of us have that thing called schadenfreude. You know, we take pleasure at the misfortune of others. We like to see someone sort of knocked down a peg.

HAMLIN: Exactly.

DANKOSKY: I guess I'm wondering how much that plays into it. Do you find babies maybe just like to see, I don't know, somebody else just get kicked around a little bit? A lot of puppet shows do that, you know.

HAMLIN: Yeah, yeah, there's two possibilities for our findings, and one of is this, you know, schadenfreude that you mentioned. So it's possible that infants are sitting there thinking, like, yes, awesome, you know, I don't like that guy, and I like seeing him be harmed.

The other possibility is that it's a very strict social judgment. They're basically just saying to themselves, you know, if you can attribute that to a baby, you know, I don't like that green bean lover, and unless that guy didn't feel the same way as me, you know, he wouldn't be harming him. So there's something about, like, oh, he must not like that green bean lover, either, because he is harming him.

And so it might be a very strict social judgment like he and I must feel the same about this green bean lover, we should probably be friends. And so you might think that they're only using the bad behavior as a signal of who they should be friends with.

And it's not completely out of the question to imagine you would want to be friends with those who share your opinions, right. It's just sort of back to the purpose of the whole study. And so I wouldn't want to go so far as to say infants are wanting this to happen to dissimilar others or enjoying that it's happening, but they may very well be using it to determine who they should hang out with later.

DANKOSKY: If you have questions or thoughts for Kiley Hamlin, a researcher who's taking a look at child behavior, you can give us a call, 800-989-TALK. Sorcha(ph) is calling from Buffalo, New York. Hi there, you're on SCIENCE FRIDAY.


DANKOSKY: Hi, what's on your mind?

SORCHA: Hi, how are you?

DANKOSKY: What's up?

SORCHA: I'm sorry, I'm sorry, I didn't hear you at first. Well, I was saying that my husband and I have seen a similar study done - we watched a documentary on it, where they used Cheerios, I think, as one of the food preferences. But it got us to thinking, when does empathy develop in a developmental stage? Really maybe that happens maybe at three or four years old because we have three children of our own, and we do see, you know, how they treat each other very poorly and sometimes in astonishing ways, and I say my God, don't do that to your sibling.

But then they start to get protective of each other at a certain point, and maybe that's a learned behavior 100 percent, but it seems like some of that has to be a natural behavior because who would be the first person to have taught their child that if they didn't already have some sort of empathy themselves. So that would be my question is when does this natural form of empathy seem to occur, and does that supersede what they maybe have been like as infants?

HAMLIN: That's a great question. So actually there is some very interesting work suggesting that even newborns find the suffering, and this is demonstrated through crying, of others aversive. So if you play newborns tapes of other newborns crying, newborns tend to cry.

If you play them tapes of themselves crying, or if you play them sort of non-crying sounds that are matched for sort of intensity, they don't cry. And so there seems to be some very early form of empathy or at least finding it aversive when others are suffering.

Throughout infancy, infants will notice when, you know, if you pretend to cry as a mom, infants will notice, and they will look concerned. I remember, you know, my nephew being extremely empathetic one day when I was upset about something and sort of patting my back even though he was only a year old and things like that.

So it's absolutely true that kids show some failures of empathy, as in, you know, they do things to each other that you're just like how is it possible that you can just run up and whale on your sibling without thinking it's bad. On the other hand, they show pretty strong empathy effects in some cases.

So what I imagine is going on is that there's all of these sort of biases that we have toward - as part of just being human that over time are just interacting with your everyday situations. So we also of course have a bias to want the toy for ourselves, and if our sibling takes it, we might, you know, whale on them even though generally we think, you know, it's not good to make others suffer.

DANKOSKY: Well, and unfortunately we've run out of time. I'm sure a lot of parents want to know even more about this. Kiley Hamlin is a Canada research chair and assistant professor of psychology at the University of British Columbia in Vancouver, Canada. Thanks so much for joining us.

HAMLIN: Thank you.

DANKOSKY: We'll be coming back right after this short break.



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