Fairness Comes Down to Individual Differences in Gut Reactions

Q&A with Christopher Frith

We all want to be treated fairly but some of us care more about fairness than others. How you choose to split money with another person in a game says a lot about your view of fairness, researchers have found. New work reveals how differences in our choices to share resources are reflected at the neural level – representing intuitive, gut-level, processes, that vary from person to person.

“Fairness is a very important concept in human society,” says Christopher Frith of University College London. “People want to be treated fairly. However, there are well-established differences in how much people value how much people value how others are treated compared to themselves.

People widely believe that humans are fundamentally self-interested and that, therefore, being fair reflects a conscious and deliberate attempt “to do the right thing,” Frith explains. “We wanted to test this idea by seeing what would happen when people were prevented from thinking too deeply about their response to fairness.”

So Frith, with colleagues Masahiko Haruno of Center for Information and Neural Networks, NICT in Osaka, Japan, and Minoru Kimura of Tamagawa University in Tokyo, conducted a brain-imaging study in which participants participated in the “ultimatum game.” This game asks participants to decide how to split a pot of money with a randomly paired partner. The participants, all recruited from Tamagawa University, would briefly see the name or face of their partner along with a proposed offer of how to split 500 yen: 250–250, 200–300, 150–350, or 100–400. They could either accept the offer, or both partners would receive nothing.

In a variant of this game, the “impunity game,” partners had to make the same choices but if the participant refused an offer, the partner would still receive his or her cut. This means that an unfair partner would not be punished. The introduction of this game was to distinguish whether people rejected less fair offers to punish their partners or as an emotional reaction to unfairness.

Before both games, the researchers first categorized all participants’ attitudes toward fairness. And during both games, the researchers introduced “cognitive load”: giving participants an extra task to do while playing. They asked participants to remember a 5-digit number that was either a random string that differed from offer to offer or a constant string (12345). Remembering the constant number was easy but remembering the random number prevented the participants from reflecting too deeply upon their decisions in the games.

The researchers found that inequity in the games elicited activity in the nucleus accumbens and amygdala, regions linked to intuitive processes. Frith spoke with CNS about the study, just published in the Journal of Cognitive Neuroscience, and its implications for our understanding of fairness and social attitudes toward others.

CNS: Can you describe what we previously knew about individual differences in attitudes toward fairness?

Frith: While there has been much behavioral research on “social-value orientation,” there has been very little work on its neural basis. In a previous brain-imaging study, Masahiko Haruno and I found that dislike of unfairness – a “prosocial” orientation – was associated with activity in the amygdala. Since the amygdala is a relatively “primitive” brain region, we suspected that this was a rapid, automatic response that did not involved much conscious reflection and we wanted to test this idea further. To understand the nature of the prosocial attitude, we explored individual differences in behavior and neutral activity when playing two simple economic games.

CNS: How would you define “social-value orientation”?

Frith: It’s an attitude to fairness. Most people tend to favor an equal distribution of resources, and a minority want to have most for themselves. Social psychologists, in particular Paul van Lange, have been studying these individual differences for about 10 years. A simple questionnaire about the sharing of money can be used to identify different types of people. Prosocials (~60%) prefer the money to be split evenly, even if this means getting less themselves. Individualists (~30%) will choose the split that gives them the most money without regard for what other people get. Competitive types (10%) want to get more than others. The behavior on this questionnaire relates to real-life behavior. Prosocial people are more cooperative, give more money to charity, and tend to vote liberal rather than conservative.

CNS: Were you surprised by any of the findings, and, if so, which ones?

Frith: We had expected that cognitive load, which eliminates conscious reflection, would not affect the behavior of our participants, as their responses to unfair offers in the ultimatum game would be intuitive rather than reflective. Our findings showed that the cognitive load actually exaggerated the individual differences, so the prosocials became more prosocial and the individualists became more individualistic. This finding was a surprise for me. I was also surprised that, while we found typical responses to unfair offers in frontal brain regions, these did not relate to individual differences in social-value orientation – their attitude to fairness.

CNS: Can you describe any novel aspects of your study design?

Frith: We used a cognitive load in an attempt to control the extent to which participants could reflect upon their decisions. This paradigm has been widely used in behavioral studies, but is relatively rare in brain-imaging studies. We also introduced the impunity game, which is a version of the ultimatum game in which the responder can refuse an unfair offer, but the unfair proposer is not punished. The results with the impunity game suggest that the accumbens and amygdala activity in prosocial individuals encodes responses designed to change situations – to achieve equity or punish.

CNS: What was the significance of the activity you saw in the nucleus accumbens and amygdala?

Frith: We believe that the activity in these “primitive” brain regions reflects intuitive, rather than reflective processes in decision-making, and that it is these intuitive processes that largely determine whether a person is selfish or prosocial.

CNS: What are the general implications of this work?

Frith: Many of us tend to think that we are basically selfish and we need to reflect upon what we are doing to overcome our selfish urges. Our research is consistent with an increasing body of evidence, that we, or at least most of us, are basically prosocial rather than selfish. It is also clear, from research of others, that our powers of reasoning and reflection can be used to overcome these prosocial urges and justify selfish behavior.

CNS: How did you personally become interested in individual differences in social-related decision making?

Frith: A very long time ago (1969), I did my Ph.D. on individual differences, but subsequently paid little attention to this aspect of psychology. More recently, I have been interested in social cognition and the neural mechanisms underlying social interactions. Most studies have tended to ignore individual differences. This is a shame because the functioning of human societies depends upon individual differences in order to achieve optimal division of labor. My collaboration with Masahiko Haruno rekindled my early interest in individual differences and we decided to look at their role in social cognition.

CNS: What are the next steps?

Frith: Our results need to be replicated using other paradigms for distinguishing intuitive and reflective aspects of decision-making. To explore the origins of social-value orientation, one could examine the role of genetic predispositions and early learning. It will also be interesting to explore the extent to which context can modify the effects of social-value orientation. For example, in some circumstances, it is to the advantage of the individualist to gain a reputation for being prosocial.

The paper “Activity in the Nucleus Accumbens and Amygdala Underlies Individual Differences in Prosocial and Individualistic Economic Choices” by Masahiko Haruno, Minoru Kimura, and Christopher D. Frith, was published in the Journal of Cognitive Neuroscience online on Feb. 24, 2014.

-Lisa M.P. Munoz