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Robert Kurzban

The Evolutionary Psychology Blog

By Robert Kurzban

Robert Kurzban is an Associate Professor at the University of Pennsylvania and author of Why Everyone (Else) Is A Hypocrite. Follow him on Twitter: @rkurzban

Guest Post: To be fair…it is a bit puzzling

Published 20 March, 2012

Today’s post is written by Alex Shaw. It’s the first of what will be a series of guests posts. – Rob K.

Today's guest blogger, Alex Shaw

A few days ago, Rob blogged about the puzzle of moral impartiality: why would individuals ever side against their allies? I thought I would use this to talk about a similarly puzzling human concern: fairness. Here’s an example from one of the psychology labs at my institution, which should help illustrate why fairness is a bit odd. This lab has several normal computers and one awesome computer with a huge screen, but no one uses the awesome computer because it would be unfair for one person to have it. This decision would appear quite irrational to any organism without a sense of fairness – shouldn’t it always be better for desirable resources to be used rather than wasted? Why do people make sacrifices in the name of fairness?

When Mitt Romney was asked why Americans care about fairness, he had a simple answer: “I think it’s about envy.” Romney’s remark highlights a tension between negative reactions to others having more (what I’ll refer to as envy) and negative reactions to inequality per se (what I’ll refer to as fairness). Romney is not alone; some economists argue that both envy and fairness are rooted in the same overall concern which they refer to as inequity aversion—a negative reaction to others being paid unequally for equal effort (Fehr & Schmidt, 1999). However, recent studies looking at the development of fairness may shed some light on whether fairness really is just about envy, and hint at why fairness may have evolved.

Vanessa LoBue and colleagues (2011) investigated children’s emerging concerns with fairness by examining 3- to 5-year-olds’ emotional reactions to unequal sharing that benefited themselves or others. Children first completed an unrelated task and then the experimenters gave out stickers to children as a reward, but did so unequally. They found that children who got the short end of the stick were sad, but those who got more were relatively happy about it. Children who received less occasionally used words like “fairness” to justify their negative reactions; yet if children were really concerned with fairness, then both children, the sticker-wealthy and the sticker-poor, should have been griping about unfairness. These results were nicely summed up by comedian Louis C.K.: “My five-year-old… The other day, one of her toys broke and she demanded that I break her sister’s toy to make it fair…and I did.” When considering his daughter’s actions, fairness is not the first word that comes to mind. What would actually demonstrate fairness is if the child with the undamaged toy demanded that someone break her own toy in order to make things fair.

Peter Blake and Katie McAuliffe (2011) examined whether children would do just that by allowing 4- to 8-year-old children to decide whether to accept or reject different distributions of resources. Children were placed in pairs; one child was assigned to the role of Decider, and then the experimenter gave some candy to both children. The Decider could either accept the distribution, or could reject the distribution in which case both children would receive nothing. All children participated in trials in which both children received equal amounts of candy and, unsurprisingly, on these trials there were very few rejections. Then, some children participated in trials in which the Decider received less. On these trials Deciders aged 4 to 8 years old rejected quite often. Other children participated in trials in which the Decider received more than the other child. Here, Deciders aged 4 to 7 years old rejected very rarely—suggesting that their rejections when they received less were based on envy, not fairness. Only 8-year-old Deciders rejected offers that favored themselves, suggesting they have a sense of fairness that goes beyond envy. The results from the 8 year-olds also go against another common suggestion for why fairness evolved: for maximizing efficiency or generosity toward others (Charness & Rabin, 2002). Upholding fairness here meant that fewer resources were being given out overall, which clearly goes against generosity.

Research I’ve conducted with Kristina Olson has made it especially clear that fairness is not about envy or generosity. We tested children aged 6 to 8 years old. The experimenter first gave out toy erasers to two non-present third parties. Then children were asked what to do with an extra eraser; they could give the eraser to one of the two children or throw it away. When giving additional erasers would allow the resource distribution to remain equal between the two third-party recipients (3rd Party Equal), children were happy to give more erasers to these recipients. However, when giving an additional eraser would create inequality such that one recipient would have more than the other (3rd Party Unequal), children opted to throw the extra eraser in the trash. Most strikingly, when the child participant was one of the recipients (1st Party Unequal), children still opted to throw the extra eraser away even when it would otherwise be given to them; they literally were in favor of wasting resources that could go to themselves in the name of fairness (Shaw & Olson, in press).

Data from Shaw & Olson, in press

In sum, children have a concern with fairness per se that emerges separately and later than envy. Should we be surprised that these concerns develop at different times? Economists and psychologists might think so, since they often discuss “inequity aversion” as one unified thing. However, from an evolutionary perspective, there is nothing deeply mystifying about this at all. Systems designed for making sure that others do not have more than oneself (envy) perform a very different function from systems designed for ensuring that things are, or at least appear, equal (fairness). Unlike fairness, whose evolutionary function is puzzling, the function of envy is obvious—being at a relative disadvantage to one’s competitors is disastrous from the standpoint of natural selection. The old joke “I don’t need to be faster than the bear; I just need to be faster than you!” comes to mind. This explains why envy often runs counter to fairness and drives people toward wanting to have more than others, though in practice people may settle for equality because that is often the best thing that they can hope for when they are currently disadvantaged.

It seems that Romney is wrong; fairness is not all about envy and even 6-year-old children have a sense of fairness that goes beyond envy (children were willing to waste their own resources to be fair). Although envy and fairness might be similar on the surface (i.e. they can both lead to the reduction of inequality), it would be a mistake to conclude that these two behaviors are based on the same mental systems with the same functional goal. As an analogy, buying a drink for an attractive stranger and buying a drink for one’s attractive sister are similar behaviors on the surface, but are likely motivated by two very different proximate motivations and ultimate goals (unless they occur in a Jonathan Haidt vignette).

The results above also demonstrate that fairness concerns cannot solely be motivated by generosity (because children were giving less resources overall). The evolutionary rationale for why people would have this destructive sense of fairness is currently unclear. In my paper above I offer a possible answer, suggesting that fairness may have evolved for signaling impartiality to others in order to avoid condemnation from others for solidifying or initiating alliances based on unequal resource sharing. However, this puzzle is far from solved.

PS: As a final note, it would be quite unfair (see what I did there?) if I did not mention the exciting infant work that is being done on fairness. Researchers have found that even infants have some expectation that resources should be distributed evenly (Geraci & Surian, 2011; Schmidt & Sommerville, 2011), and by the time infants are 19 months old they are even surprised when individuals get paid the same amount for unequal work (Sloane, Baillargeon, & Premack). This work is certainly worth reading for those interested in what aspects of fairness are especially early-emerging.


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.

Charness, G., & Rabin, M. (2002). Understanding social preferences with simple tests.

Quarterly Journal of Economics, 117, 817–869.

Fehr, E., & Schmidt, K. M. (1999). A theory of fairness, competition, and cooperation.

The Quarterly Journal of Economics, 114, 817-868.

Geraci, A. & Surian, L. (2011) The developmental roots of fairness: Infants’ reactions

to equal and unequal distributions of resources. Developmental Science, 14, 1012-1020.

LoBue, V., Nishida, T., Chiong, C., DeLoache, J., & Haidt, J. (2011). When Getting

Something Good is Bad: Even Three-year-olds React to Inequality. Social Development, 20, 154-170.

Shaw, A. & Olson, K.R. (in press). Children discard a resource to avoid inequity.

Journal of Experimental Psychology: General.

Sloane, S., Baillargeon, R., & Premack, D. (2012). Do Infants Have a Sense of

Fairness? Psychological Science, 23, 196-204.

Schmidt, M.F. & Sommerville, J.A. (2011). Fairness expections and altruistic sharing

in 15-month-old human infants. PLoS ONE, 6, e23223.


Copyright Alex Shaw. All Rights Reserved. 

  • http://popsych.blogspot.com/ Jesse Marczyk

    Not sure if you have this reference already, but you’d probably enjoy it:
    Pillutla, M.M. & Murnighan, J.K. (2003). Fairness in bargaining. Social Justice Research, 16, 241- 262

    • Alex Shaw

      I was familiar with this, but thanks for the post. I agree with the authors that fairness is often used as a label for a lot of things, but I think there is a “there” there.

  • http://www.facebook.com/the.tapeworm Denis Tatone

    Great post and great paper, Alex! I really enjoyed how you kept social welfare, inequity aversion, and social comparison apart. Social psychology would surely benefit by theoretical dissections of this kind! In the paper, you rightly mentioned that children may use inequity aversion to signal their fair attitude to the adult. However, they could have gained favor with the adult also by giving the extra resource to the experimenter’s friend – something they didn’t do. Wildly speculating, I’d say that the signaled qualities (propensity to favoritism vs. propensity to impartial behavior) are differently valued by different audiences – and children may be sensitive to this. To flesh out my argument a bit: it is unlikely that adults would gain any real benefit by children’s favoritism toward them, while on the other hand they may incentivize fairness by generating goodwill and affection towards the impartial children. On the contrary, favoritism toward a friend of a possible ally may be valued more in the presence of peers as a means of coalition formation.

    • Alex Shaw

      Thank you for the kind remarks about my paper. I think the question of what exactly these fairness concerns are meant to signal is an open and important one. I don’t think that children’s signaling is something that is only aimed at adults or based on the power asymmetry between children and adults. My guess is that children attempt to appear fair to their peers. We know that adults engage in a similar sense of “destructive” inequity aversion (Shaw & Knobe, in press). They think it is better to not give an additional dollar raise to one of two employees if doing so will create inequality, even though the two employees don’t know each other and won’t know what the other gets. Therefore, I think the real puzzle is to explain what people (both children and adults) are trying to signal with their inequity aversion.

      I agree with the idea that different audiences and circumstances will shift one’s focus on signaling impartiality versus initiating or strengthening alliances (I’ve explored this a bit and competition seems to be one thing that makes children value relative advantage or alliance formation more). The suggestion about behaving differently toward one’s friends is right on as well. An ideal position for you would be one in which you could signal to your allies that you favor them and to show favoritism toward others as a means of initiating alliances with them, while hiding your attempts to do so by appearing impartial to others (non-allies). My research is currently focused on exploring this connection between inequity aversion, impartiality, and alliances. Hope I’ll have better answers for you sometime soon.

Copyright 2012 Robert Kurzban, all rights reserved.

Opinions expressed in this blog do not reflect the opinions of the editorial staff of the journal.