Babies expect fairness, and they prefer people who behave with fairness

© 2020 Gwen Dewar, Ph.D., all rights reserved


Babies expect adults to share resources equally. They prefer people who behave with fairness. But babies are also learning about selfishness and favoritism. Can we become the role models our children deserve?

Everyone should get a fair share.

It's the organizing principle of hunter-gatherer societies, and a familiar concept worldwide.

Even in cultures that promote hierarchy, people tend to resent gross inequality.

In experimental games, people around the world impose penalties on players who attempt to divide up prizes in a skewed, discriminatory way (Ensminger and Henrich 2014; Henrich et al 2006).

But when does it start? How early in life do we begin to notice inequality? To expect fairness? To care about the way resources are divided up?

You might guess that it happens during the preschool years. That period between 3 and 5 years, when children are highly mobile, talkative, and ready to fight for their interests.

Such children have many opportunities to witness the division of resources they care about, like treats and toys. They have the verbal skills to negotiate. So perhaps this is when kids start learning about the fair allocation of goods.

It sounds plausible, but it's wrong.

As it turns out, babies know quite a bit about fairness.

They seem to expect that adults will distribute resources equally.

They seem to anticipate that acts of unfairness will provoke our condemnation.

And -- given the choice -- babies show a preference fair-minded individuals. They will selectively approach adults who they've seen treat others with fairness.

How do we know? What factors influence our children? And what can we do to nurture a sense of fairness? Here are the details.

Experimental research: Babies expect adults to divide up resources in a fair, equal way

The first evidence came from experiments on older infants living in the United States. 

Marco Schmidt and Jessica Sommerville showed 37 babies (aged 15 months) several mini-movies -- video clips depicting a pair of women sitting at a dining table.

Each video clip began the same way.

  1. The diners wait.
  2. A third person (let's call her the "Distributor") arrives with food.
  3. The diners eye the food and make enthusiastic comments. "Yummy!"

But what happened next varied from one clip to the next.

  • In some video clips, the Distributor gave each diner the same amount of food (e.g., each woman received two graham crackers).
  • In other video clips, the Distributor divided the food unequally (e.g., one woman received a single graham cracker, while another received three).
experimental conditions - equal and unequal distribution of food - copyright Schmidt and Sommerville 2011

So. Two different endings -- one fair, one unfair. How did the babies feel about it?

The researchers couldn't interview the babies to find out. These infants hadn't yet developed the necessary language skills.

But there is another way to gain insight into a baby's mind.

Scientists have long established that babies tend to look longer at events that surprise them. Thus, if you measure looking times, and compare them, you can get a feeling for what babies expect.

A long stare suggests that something has violated the baby's expectations.

What happened in the case of the graham cracker vignettes?

Babies acted as if they were surprised by the unequal distribution of food. They stared longer at the unfair outcome.

And the babies' surprise wasn't focused on the food per se. It was the human element that mattered.

We know this because the researchers ran a control condition featuring video clips without human actors. Some video clips showed a table with equal amounts of food. Others showed food distributed unequally:


When shown these video clips, the babies spent the same amount of time looking -- regardless of the outcome (Schmidt and Sommerville 2011).

So the babies' expectations were focused on people. Somehow, by the age of 15 months, these babies had learned a cultural norm of fairness. When people distribute food, they are supposed to give every recipient an equal portion.

Subsequent studies have replicated the effect, and documented expectations of fairness in even younger babies (Sommerville and Enright 2018).

For example, a lab in Italy has reported expectations of fairness in 10-month-old babies (Meristo et al 2015).

Another research group -- in the United States -- found evidence for expectations of fairness in both 9-month-old and 4-month-old infants (Buyukozer Dawkins et al 2019).

It seems, then, that we're on pretty solid ground if we assume that babies -- by the beginning of their first year -- understand something about equitable sharing.

But does that tell us that babies think fairness is good?

Are babies little egalitarians? Do they actually endorse the equal distribution of resources?

That's hard to say. Maybe babies don't have any moral intuitions or preferences about it. They just have a sense for what's normal. They've learned that people usually divide things up in an equitable way.

But there is intriguing evidence to the contrary. 

Study: Babies act as if egalitarian sharing is a distinguishing characteristic of the "good guys"

Surian and colleagues (2018) tested the idea by presenting animated video clips to a group of 14-month-old babies in Japan.

The researchers began by introducing the infants to a couple of cartoon characters:

  • One character was prosocial. The babies watched as this character offered assistance to someone trying to climb up a hill.
  • The other character was antagonistic. It actively thwarted the hiker's efforts.

Then, the babies watched a new set of video clips. Each clip featured one of the previously-encountered characters, but now the characters were acting as Distributors -- allocating red berries to a pair of would-be recipients.

As in the live-action "graham cracker" experiments, events varied from one video clip to the next.

  • In some clips, babies witnessed the Distributor behaving fairly. Each recipient received a berry.
  • In other clips, babies saw the Distributor act unfairly. One individual received two berries. The other got nothing.
Distributing berries: Equal vs unequal test events (© Surian et al 2018)

And once again, the researchers tested the effects of fair and unfair distribution scenarios on a baby's looking time. The outcome?

Babies still had expectations regarding fairness, but they seemed to modify their expectations based on a character's prior behavior.

When babies saw the previously helpful character being unfair, they acted surprised. They stared longer.

Babies also acted surprised when the observed the previously antagonistic character acting fairly.

It's a result that suggests babies do more than expect fairness. They expect fairness from a specific type of individual -- someone who is helpful or kind. Fairness is a distinguishing characteristic of "the good guys."

And this interpretation gets support from another study -- a study testing babies' expectations about praise and censure.

Study: Babies anticipate that we'll condemn acts of unfairness

Researchers began by replicating the "graham cracker" procedure used by Schmidt and Sommerville: They presented 15-month-old babies with video clips of a Demonstrator handing out food to a couple of women (Deschamps et al 2016). 

But this time, researchers added a new step. Immediately after each video clip ended, the presented babies with a close-up of the Distributor's face.

The face didn't move or speak. The Distributor remained still and quiet. And while the babies watched this face, there was a voice-over. A stranger's voice -- filled with emotion -- was making comments about the Distributor.

The nature of the comments varied.

  • After some clips, the voice enthusiastically praised the Distributor. Babies heard the voice say things like: "She's a good girl. She did a good job!"
  • After other clips, the voice admonished the Distributor, saying things like: "She's a bad girl. She did a bad job!"

How did babies react? It depended on what they had witnessed in the preceding video clip.

For example, if they had just seen the Distributor dividing up resources unfairly, the babies seem to expect disapproval. They didn't look very long when the voice admonished the Distributor.

But if the voice praised the unfair Distributor, the babies stared.

Babies also show an interesting developmental pattern: Individuals who expect fairness are more likely to engage in generous acts of sharing.

For evidence, let's go back to the original experiments by Schmidt and Sommerville.

We saw that the babies acted surprised when the Distributor behaved unfairly. But that was the result for babies on average.

Not every baby followed the trend. Some babies didn't act surprised by the unequal distribution of food.

So Schmidt and Sommerville wondered. Does a baby's personal expectations have any bearing on the way he or she treats other people? Are expectations of fairness linked with personal acts of generosity?

To find out, the researchers conducted a follow-up test. It went like this.

  1. Each baby sat on his or her mothers' lap. The baby was offered two toys.
  2. The researchers noted the baby's favorite, and then asked the baby to hold both toys (one in each hand).
  3. Next, a stranger arrived and asked for a toy. ("Can I have one?")

Three outcomes were possible.

  • A baby could hand the stranger the preferred toy.
  • A baby could hand the stranger the non-preferred toy.
  • Or a baby could fail to respond altogether.
Experimental image of baby sharing preferred toy with stranger - Schmidt and Sommerville 2011

What happened?

Most babies handed over a toy, but there was an interesting difference in the level of generosity shown.

Among babies who shared, those who had expected fairness in the previous experiment were very likely to share their preferred toy.

By contrast, babies who didn't expect fairness were less altruistic. The vast majority (12 out of 13) handed over their non-preferred toy.

As the authors argue, this suggests that sharing and fairness expectations are developmentally linked. Noticing fairness -- viewing it as normal -- was connected with a baby's willingness to share highly-valued objects.

Finally, there's evidence that babies actively prefer individuals who distribute resources in a fair, equitable way.


Fair vs unfair food distribution (© Lucca et al 2018)

In an experiment on 13- and 17-month-old infants, Kelsey Lucca and colleagues (2018) repeated the graham cracker procedure.

Once again, babies watched video clips of human actors sitting at a dining table. And once again, the endings varied.

  • One clip featured a woman giving two diners an equal number of crackers to eat. 
  • Another clip showed a different woman distributing grossly unequal portions.

Each baby viewed both clips, and, immediately afterwards, the baby was presented with an opportunity.

The baby was in a room with two, large monitors. As you can see from the photo, each monitor featured a different Distributor, and each Distributor appeared to be gazing at the viewer...and offering a toy.


Just beneath each monitor was a kind of delivery apparatus -- a yellow tube emptying into a container.

The researchers designed this set-up to create the illusion that the on-screen women could send their toys through the tubes and into the containers below. And that's just what each woman appeared to do.

Babies watched these actions, which occurred simultaneously. Then they were given a choice. They could approach one of the women and retrieve a toy.

But which woman would they approach? The fair Distributor? Or the unfair Distributor?

The babies voted with their feet, and most showed the same preference. About 80% (24 out of 30) went for the woman who had acted fairly. 

How do babies develop these notions? Everyday interactions -- including those with siblings -- play a role.

The behavior we observe in these experiments seems spontaneous. Babies weren't deliberately trained to expect equal portions. Nobody instructed told them to expect fairness from the "good guys." Nobody taught them to prefer people who follow egalitarian principles.

And, as I mentioned in the introduction, hunter-gatherers -- the peoples whose life-ways most closely match those of our ancestors -- are intensely egalitarian.

Hunter-gatherers don't tolerate individuals who try to "get above themselves." Such people are ridiculed, sanctioned, and ostracized.

So there's a case to be made that egalitarian ideas are fundamental to the human playbook. An aspect of human nature.

But that doesn't mean it just happens.

A crucial point about "human nature" is that we learn. If we tend to develop along certain lines, it usually isn't because we're "hardwired" to turn out the same way, regardless of environmental inputs. Our experiences shape us.

This is undoubtedly true of attitudes and preferences about egalitarianism and fairness. The evidence indicates that baby's experiences are important.

For example, if fairness is something we learn, then we ought to see a correlation with learning opportunities: Babies should develop expectations of fairness earlier if they are exposed to more frequent examples of people dividing up resources. 

And this prediction is consistent with a study by Talee Ziv and Jessica Sommerville.

The researchers tracked 150 babies for nine months, and found that the development of fairness expectations had little to do with the state of a child's motor skills or language ability.

Instead, a key predictor was having siblings (Ziv and Sommerville 2016). Kids developed fairness expectations earlier in life when there was somebody at home to share with.

And let's confront another reality. Babies don't always assume that we'll distribute resources equally. At some point along the way, they learn about corrupt power-grabs and favoritism.

We saw hints of that in the animated "good guy, bad guy experiment." Babies didn't expect the antagonistic character to distribute resources fairly.

But in that experiment, babies didn't know anything about the potential recipients. They had no reason to predict which individuals the unfair Distributor would favor.

What if we provide this information? Do babies expect that certain types of individuals will get more than their fair share? That authority figures will prop up aggressors or elites?

These are precisely the findings of Elizabeth Enright and her colleagues (2017).

The researchers performed their experiments using two puppets, and they began by confirming that 17-month-old babies will respond to puppets just as they do to human beings:

When a man distributed unequal portions to these puppets, and the babies acted surprised.

But that's when babies don't have any background information about the two puppet characters.

So the researchers ran another experiment, one that included a prologue.

Babies watched the puppets interact with each other, and noticed that one was puppet was stronger, bossier, more dominant.

For example, when the two puppets competed to sit on a fancy chair, one came out the clear winner. He got his way.

After seeing this power struggle, the babies were randomly assigned to watch different distribution scenarios.

  • Some saw a human experimenter dole out equal portions to the puppets.
  • Others witnessed the experimenter giving out unequal portions.

And the results?

When the Distributor gave more to the dominant puppet, the babies took this in their stride.

It was the fair outcome -- an equitable distribution of prizes -- that made babies do the double-take (Enright et al 2017).

So what's the practical takeaway?

We've got one more reason to treat our infants as thinking, feeling, socially perceptive beings.

Babies are doing much more than learning to crawl, walk, and talk.

From an an early age, they are watching us. Watching and figuring things out, and not only when we're directly engaging them in conversation.

As important as direct engagement is for a baby's development, it's just one piece of the puzzle.

Babies also pay attention to -- and learn from -- the social interactions of other people.

They absorb information about the relationships of third parties.

They learn about social norms, power plays, and morality. 

So if you've heard of babies characterized as "little psychologists" (learning about other people's thoughts and feelings), and "little physicists" (learning about gravity and physical properties of objects), here's another job title to the list: Our babies are also "little anthropologists."

They aren't just studying our fine words and ideals. They are studying our actual behavior, warts and all. And we couldn't stop them, even if we wanted to. They learn from our example.

So let's strive to show them our best.

More reading

Can we teach empathy and compassion? Can we help our children develop better social skills? See my evidence-based tips for nurturing empathy, and these Parenting Science social skills activities.

And for more fascinating information about your baby's developing mind, check out these Parenting Science articles:

References: Babies expect fairness

Burns MP and Sommerville JA. 2014. "I pick you": the impact of fairness and race on infants' selection of social partners. Front Psychol. 2014 Feb 12;5:93.

Buyukozer Dawkins M, Sloane S, Baillargeon R. 2019. Do Infants in the First Year of Life Expect Equal Resource Allocations? Front Psychol. 10:116.

DesChamps TD, Eason AE, Sommerville JA. 2015. Infants Associate Praise and Admonishment with Fair and Unfair Individuals. Infancy. 21(4):478-504.

Enright EA, Gweon H, Sommerville JA. 2017. 'To the victor go the spoils': Infants expect resources to align with dominance structures. Cognition. 164:8-21.

Ensminger J and Henrich J (eds). 2014. Experimenting with Social Norms: Fairness and Punishment in Cross-Cultural Perspective. Russel Sage Foundation.

Hamlin JK and Wynn K. 2011. Young infants prefer prosocial to antisocial others. Cogn Dev. 26(1):30-39.

Henrich J, McElreath R, Barr A, Ensminger J, Barrett C, Bolyanatz A, Cardenas JC, Gurven M, Gwako E, Henrich N, Lesorogol C, Marlowe F, Tracer D, Ziker J. 2006. Costly punishment across human societies. Science. 312(5781):1767-70.

Lucca K, Pospisil J, and Sommerville JA. 2018. Fairness informs social decision making in infancy. PLoS One. 13(2):e0192848.

Meristo M, Strid K, and Surian L. 2016. Preverbal Infants' Ability to Encode the Outcome of Distributive Actions. Infancy 21(3): 353-372.

Schmidt MF and Sommerville JA. 2011. Fairness expectations and altruistic sharing in 15-month-old human infants. PLoS One. 6(10):e23223.

Sommerville JA and Enright EA. 2018. The origins of infants' fairness concerns and links to prosocial behavior. Curr Opin Psychol. 20:117-121

Surian L, Ueno M, Itakura S, Meristo M. 2018. Do Infants Attribute Moral Traits? Fourteen-Month-Olds' Expectations of Fairness Are Affected by Agents' Antisocial Actions. Front Psychol. 9:1649. 

Xu J, Saether L, Sommerville JA. 2016. Experience facilitates the emergence of sharing behavior among 7.5-month-old infants. Dev Psychol. 52(11):1732-1743

Ziv T and Sommerville JA. 2017. Developmental Differences in Infants' Fairness Expectations From 6 to 15 Months of Age. Child Dev. 88(6):1930-1951.

Image credits for "Babies expect fairness"

Image of two babies interacting by santypan/ istock

Images credited to Schmidt and Sommerville appear under creative commons license. The images come from the paper (Schmidt and Sommerville 2011) cited in the references section above.

The same creative commons license applies to images credited to Surian et al (2018) and Lucca et al (2018).

Images of rectangles attempting to climb brown hill reproduced from a screenshot of a video posted by Uzefovsky and colleagues (creative commons license). I have modified the images (with arrows, hearts, and text) to convey the action.

Content of "Babies expect fairness" last modified 5/22/20


Copyright © 2006-2020 by Gwen Dewar, Ph.D.; all rights reserved.
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