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024: How (and when) does my child understand fairness?
5th February 2017 • Your Parenting Mojo - Respectful, research-based parenting ideas to help kids thrive • Jen Lumanlan
00:00:00 00:43:28

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We talked a while ago about sharing, and how you can understand the developmental processes that your child needs to go through before s/he truly understands what it means to share.

One of the inputs to sharing behavior is an understanding of what is fair, and Drs. Peter Blake and Katie McAuliffe talk us through what we know about what children understand about fairness.  This episode will help you to understand how much of the idea of fairness is naturally culturally transmitted to children and what you can do to encourage a sense of fairness in your child, which is important for their own social well-being and for the benefit of our society – this has implications for ideas like the development of perceptions about race and gender that we’ll be talking more about in upcoming episodes.


Blake, P.R., Corbit, J., Callaghan, T.C., & Warneken, F. (2016). Give as I give: Adult influence on children’s giving in two cultures. Journal of Experimental Child Psychology 152, 149-160. DOI: 10.1016/j.jecp.2016.07.010

Blake, P.R., McAuliffe, K., Corbit, J., Callaghan, T.C., Barry, O, Bowie, A., Kleutsch, L., Kramer, K.L., Ross, E., Vongsachang, H., Wrangham, R., & Warneken, F. (2015). The ontogeny of fairness in seven societies. Nature 528, 258-261. DOI:10.1038/nature15703

Blake, P.R., Rand, D.G., Tingley, D., & Warneken, F. (2015). The shadow of the future promotes cooperation in a repeated prisoner’s dilemma for children. Scientific Reports 5, Article number 14559. DOI: 10.1038/srep14559

Blake, P.R., & McAuliffe, K. (2011). “I had so much it didn’t seem fair”: Eight-year-olds reject two forms of inequity. Cognition 120, 215-224. DOI: 10.1016/j.cognition.2011.04.006

Bronfenbrenner, U. (1979). The ecology of human development: Experiments by nature and design. Cambridge, MA: Harvard University Press.

Chernyak, N., & Kushnir, T. (2013). Giving preschoolers choice increases sharing behavior. Psychological Science 24, 1971-1979.

Jordan, J.J., McAuliffe, K., & Warneken, F. (2014). Development of in-group favoritism in children’s third-party punishment of selfishness. Proceedings of the National Academy of Sciences. 111(35), 12710-12715. DOI: 10.1073/pnas.1402280111

McAuliffe, K., Blake, P.R., Steinbeis, N., & Warneken, F. (2017). The developmental foundations of human fairness.  Nature (Human Behavior) 1 (Article 00042), 1-9.

McAuliffe, K., Jordan, J.J., & Warneken, F. (2015). Costly third-party punishment in young children. Cognition 134, 1-10. DOI: 10.1016/j.cognition.2014.08.013

Schmuckler, M.A. (2001). What is ecological validity? A dimensional analysis. Infancy 2(4), 419-436. Full article available at:


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Jen:                                      [00:30]                   Hello and welcome to today’s episode of Your Parenting Mojo, which is called What Do Children Understand About Fairness? And I have two very special guests with me to discuss this topic. Dr Peter Blake earned has doctorate in education at Harvard University and is currently an Assistant Professor at Boston University’s Department of Psychological and Brain Sciences. His research focuses on three important foundations of human life, cooperation, fairness and ownership, and so he asks questions in his research like when should you share and when should you compete for resources? Is equal always fair or can you sometimes keep more for yourself? And how do you know when a toy is owned and what does that mean? Right now he’s working on extending projects, the different cultures, so we can better understand whether children in all cultures develop in similar ways at similar times and what cultural variables influence that development. Welcome Dr Blake.

Dr. Blake:                           [01:21]                   Thank you.

Jen:                                      [01:22]                   And Dr. Katie McAuliffe is an assistant professor in the Department of Psychology at Boston College, which I just learned as different from Boston University. She two studies, the development and evolution of cooperation in humans with a special focus on how children acquire and enforced fairness norms. She’s made the rounds of Harvard, Yale, and Cambridge, and her educational career. I think the only one she’s missing is Oxford. Welcome Dr McAuliffe.

Dr. McAuliffe:                   [01:44]                   Hi; nice to be here. Thanks.

Jen:                                      [01:45]                   Thank you so much for being here. So let’s start with a question that seems really simple, but I’m guessing there’s probably more to it than, than maybe I might imagine. Can you tell us what fairness is?

Dr. Blake:                           [01:56]                   Yeah, that’s, that’s the big question and it is a very complicated answer. So fairness is a, is a very complex concept, particularly for adults and we know that equal is not always fair, but equality does provide a kind of starting point for us to understand how children figure out what is fair and what is not. So we tend to focus our research in a couple of ways. One way is that we focus on the allocation of resources which has also been called distributive justice, how you distribute resources between people. So we focus on that aspect of fairness as opposed to social status and things like that. And we also focus around this idea of equality and particularly what happens. How did children respond when they get less and get more than other kids.

Dr. McAuliffe:                   [02:51]                   And I think studying how fairness develops in childhood is a nice way of showing how flexible the concept is. Because when we look at how children begin to think about fairness, you can see that what it means to be fair really varies depending on whether you’re a two year old or an eight year old.

Jen:                                      [03:08]                   How does that change?

Dr. McAuliffe:                   [03:09]                   Well, we can kind of get into that with lots of different studies, but maybe a sort of broad way to characterize the change, and this is based on work that was really done in the seventies is that fairness tends to start out as being quite self focused. So I want to make sure that I’m getting a good deal, and it goes through a period of sort of really caring about equality as Peter said, as a sort of benchmark of justice and then it becomes much more nuanced or you can take different perspectives into account and understand that sometimes someone is more deserving or more needy and therefore inequality is acceptable under certain situations.

Jen:                                      [03:46]                   Most of the parents listening to this show are parents of toddlers and, and some parents of preschoolers. And I know that you start to study children kind of around about age four or five years. Why don’t you study children younger than that? What is it that makes that difficult?

Dr. Blake:                           [04:01]                   It’s primarily that there’s very different methods that are used for, for infants and toddlers, largely because they don’t have the verbal skills yet to do some of the tasks. We have tried to test children as young as three in some of our experiments. That works fine, but younger than that, we’ve found that they don’t do well on our tasks, but other people do research…have done research on infants. And one key thing that they found going back to this idea of equality is that even at about 15 months of age, infants expect resources to be distributed equally between two people. And they expect adults to divide things like food and toys equally. They’re surprised when this doesn’t happen. And this has been shown in several different infant studies now. So that goes back to this idea of equality is a kind of foundation now where that comes from. This could have been learned through experience 15 months of age is still quite a long time of life, but they’re learning just by observing this, this isn’t based on their own behavior. So they’re not constructing this idea of equality from their own experience.

Jen:                                      [05:13]                   So are you saying that if I always make sure that I get a bigger piece of chocolate cake than my husband does, that my daughter might not understand fairness to mean equal?

Dr. Blake:                           [05:22]                   I wouldn’t go that far. But by the time we get up to about three years of age you can ask it explicitly what they think is fair. And one of the things that we’ve found in some of our studies is that when we give children a set of stickers, for example, and we asked them, how should you divide this up with another child? They’ll say, yeah, I should give half. But then when we give them a chance to actually give to the other child, they’ll keep more for themselves. So they, they recognize that there’s this norm of an equal split in that context, but they don’t follow it; they tend to favor themselves. And this is, uh, this idea of a bias to favor oneself is something we see in other variations of studies, including the big ones that Katie and I have worked on together.

Dr. McAuliffe:                   [06:10]                   And I think Peter is pointing to a really important distinction in the types of studies that are done looking at fairness sort of this children’s expectations of what ought to be done versus what they actually do. And so most of our work really focuses on children’s behavior, so we put them into these games inspired by behavioral economics where they’re making decisions that affect both their own payouts as well as a partners payout. And I think this is part of the reason why we tend to start around for those contingencies and the payoffs and the structures of the games are just hard to understand for children younger than than that age.

Dr. Blake:                           [06:45]                   And when we say economics to kids, we use candy and stickers as our currency.

Jen:                                      [06:53]                   Both things that are very attractive to kids. And so I’ve seen a bunch of, you know, I’ve read a lot of your papers and I’ve seen a bunch of diagrams of how you do these experiments. Can you just maybe talk us through one of these experiments and how you actually test this kind of thing?

Dr. McAuliffe:                   [07:08]                   Yeah. So the one that Peter and I started back when we were Grad students at Harvard is called the inequity game and this game that we developed that we’ve subsequently used across a lot of different papers and the way this works is we go out to different public areas and we recruit two children, typically children that do not know one another to play a face to face game. And in this game, one child makes all the decisions so they have control of this apparatus and they are making decisions that affect both how many Skittles they get as well as how many Skittles their partner gets. So they’re called the actor. They’re the one who’s making the decisions that we care about. Then the other participant is assigned the role of recipient. They’re sort of passive in this game. They just get whatever they get based on the actor’s decisions.

Dr. McAuliffe:                   [07:52]                   Uh, and then from there the structure is really very simple. So an experimenter, we’ll put different amounts of candies on two trays, one for the actor, one for the recipient. And essentially the actor just decides, do I want to accept that allocation or do I want to reject it? And now if they accept it, they’ll get some candy and the recipient will get some candy. But if they reject it, and this is the interesting part, the candy gets put into a middle bowl and nobody gets to take those candies home. So it’s an all or nothing game. And we use this game to, to kind of understand what distributions children will accept and which ones they’ll reject. And sort of the simplest distinction is one where they’re either getting an equal pay off. So the actor is getting one candy and their partner is getting one candy.

Dr. McAuliffe:                   [08:35]                   And as you might imagine, children tend to be very happy to accept those allocations, but then we can put them in a situation where they’re getting less than their partner. So let’s say they’re getting one candy and their partner is getting four. So this is an interesting dilemma because now you know, presumably the actor wants that one Skittle, but you know, they don’t really want the partner to get more than them. So they have to decide, am I okay accepting one thing and letting my partner have more than me or would I rather we both get nothing. And what we find is that even children at the bottom end of our age range, so four year olds will reject those allocations.

Jen:                                      [09:09]                   Really?

Dr. McAuliffe:                   [09:10]                   Yeah. That means effectively they’re paying the price of one Skittle to prevent their partner from getting more than them. So that’s what you might’ve seen in our papers as that’s labeled disadvantageous inequity aversion. So it’s an aversion to pay off where I’m getting less than someone else. And then we can also in using this exact same game, look at the reverse form of this allocation. So one where the actor gets for candies and their partner gets one. So now you know, they get this amazing payoff. Their partner is getting less and now they face this sort of different dilemma, which is now I really want these four candies, but maybe I know it’s unfair to my partner. So should I accept them and let them get less than me or should I reject it and make, make us both get nothing? And they’re, what you might expect having interacted with children, is that young children are totally fine with those outcomes.

Jen:                                      [10:00]                   Did they ever take the four Skittles and then away from the game, give one to the other kid?

Dr. McAuliffe:                   [10:05]                   So that kind of...