The Neuroscience of Distributive Justice

Since the emergence of philosophical thought, an unresolved debate has persisted about a general definition of justice and equity. An aspect of that debate involves distributive justice, or how goods and benefits should be dispersed throughout a society in a fair and just manner. As an extreme example of this dilemma, imagine you are commissioned to deliver 100 lbs. of food to a famine-stricken region that consists of two villages a hundred miles apart. If you deliver half of the food to the first village, then travel to the second, 30 lbs. of the food will spoil during the trip. Would you deliver all of the food to the first village, or provide each village with only 35 lbs. of food in the pursuit of equity? What if you knew that 35 lbs. of food was not enough to fully alleviate the suffering of either village until the next shipment of food arrived?

Philosophers have offered several solutions to debates of this nature. Utilitarianism, a concept with ancient roots but most frequently associated with Jeremy Bentham and John Stuart Mill, asserts that one’s primary goal should be the achievement of a maximal amount of good or happiness. In the situation described above, a utilitarian might opt to deliver all of the food to the first village. This would maximize the sum of individual fulfillment, while the halving of the food would maintain a static level of suffering. Thus, delivering all of the food to the first village is the greater good.

Another approach to such a quandary is known as deontological ethics, which emphasizes not the consequences of one’s actions, but whether the actions are right or wrong, just or unjust. From a deontological perspective, it would be unjust to distribute the food unequally. A desire for some degree of fairness in all dealings seems to be a universal human trait, something deontologists point to in support of their doctrine.

Another question about distributive justice involves the extent to which emotion plays a role in the decisions it calls for. Many philosophers, both ancient and contemporary, assert that rational thinking is what allows us to make choices in difficult situations like the one above. Others argue that the processes behind those decisions cannot be devoid of an emotional influence, specifically one of an empathetic or sympathetic nature.

A study in this week’s Science examines distributive justice from a neural perspective, asking: what areas of the brain are active when we make such decisions? To find out, researchers used fMRI to scan the brains of 26 adults while they made decisions about allocating money to groups of children living in an orphanage in Uganda. During the allocations, the participants were forced to make a number of decisions that involved trade-offs between efficiency (analogous to Utilitarianism) and equity (deontology).

The investigators found that distinct neural regions are activated in the consideration of equity and efficiency. The putamen, a mid-brain structure that forms part of the dorsal striatum, seemed to be correlated specifically with efficiency. On the other hand, activity in the bilateral insular cortex was correlated with inequity. Regions of the caudate were activated by both. They also found that individual differences in aversion to inequity corresponded with higher neural activity in the insula.

Overall, the participants showed the greatest neural reaction to an inequitable distribution of food, leading the authors of the study to speculate that distributive decisions are made to avoid inequality more so than to engender efficiency. Thus, the results of this experiment seem to support the deontological argument. As the insular cortex is thought to play an important role in emotional processing, the experiment also indicates that our decisions are not devoid of an emotional element (contrary to the beliefs of Kant and Plato).

Thus, the imaging evidence from this study may help to explain why the debate over distributive justice has never been resolved. The concepts of equity and efficiency, and their respective values, are deeply rooted in our brains. Perhaps evolution never resulted in the disappearance of one or the other because they both are valuable in the decision-making process, depending on the situation. When all is said and done, though, it may be that the evolutionary value of fairness overrides that of efficiency.

Hsu, M., Anen, C., Quartz, S.R. (2008). The Right and the Good: Distributive Justice and Neural Encoding of Equity and Efficiency. Science, 320 (5879), 1092-1095. DOI:10.1126/science.1153651

Does Money Affect the Way You Think?

Money, perhaps more so than any other modern symbol, can elicit a vast array of emotions (depending to a large degree on its abundance in one’s life), including yearning, anxiety, pride, greed, envy, depression, and happiness. Of course there is not simply a direct correlation with money and any one of these emotional states, such as more money equaling more happiness or vice versa. In fact, past research has found that the effects money has on one’s well-being can be very disparate. On one hand, having more money may be good for your health and emotional state. On the other, people who place a high value on money have been found to have poorer social relationships than those who are more moderate in their view toward the attainment of wealth.

A group of researchers recently conducted a series of experiments to explore this paradoxical aspect of affluence. They formulated two hypotheses about the dual nature of money in the modern world. First, since money is the basis of most exchange in today’s society, they suggested that the thought of money should make people more focused on cost-benefit analyses and a market-pricing view of their environment. They thought that this perspective might encourage more emphasis on individual performance, since money is often correlated with the completion of personal tasks in our business-based economy. They predicted people with money on their mind would think of life in terms of inputs and outputs, with an awareness that greater input should result in a greater output.

They also hypothesized that the market mentality, while beneficial for personal performance, might hinder one’s ability to interact socially. Because it fosters a focus on individual performance, it might cause a decrease in sensitivity towards the needs of others.

To test their hypotheses, they used several different methods of exposing participants to money-related cues, while attempting to make the cues subtle enough that the subjects wouldn’t be aware of their presence. In one experiment, some participants sat at a desk with a screensaver that depicted money, while others saw screensavers of fish or flowers. In another, participants had to organize phrases that were or were not related to money, such as “I cashed a check” or “I wrote the letter”. Several other methods of exposure to money cues were used.

After being exposed to the cues, the participants were put in various social situations that tested their desire to be helpful, generous, sociable, or industrious. For example, to test willingness to help, a confederate would walk by and drop a handful of pencils (27 to be exact). Or, in another situation, a confused colleague would ask for assistance in understanding a task they were attempting to complete. Those who were exposed to money cues picked up fewer pencils, and those who weren’t spent 120% more time helping the confused colleague.

When given an opportunity to donate a portion of $2 the participants were given at the start of the study, those who had been reminded of money donated 39% of their payment, while those who hadn’t been donated 67%. They also, when allowed to situate the chairs in a room while waiting for another person to arrive, put more distance between their chair and the other person’s than the money-naïve group. When given a list of solo vs. group activities to take part in, the money-exposed group chose more individual activities than the control group (even when some activities included family members and friends).

With the choice of working on a task alone or getting help from a peer, the money-reminded participants chose to work alone, even though it meant doing more work. When faced with a challenging task, they spent 48% more time working at it before seeking help from the experimenter.

The researchers suggest these results may appear because a money-oriented person is focused on the inputs and outputs of the market, a view that tends to lead to an emphasis on individualization and self-sufficiency. They found no changes in emotion between the two groups, and thus assert that the differences in behavior are probably not due to a distrusting of others. Additionally, the fact that those who were reminded of money chose to persist on a task before asking for help indicates the results are not based purely on selfishness, as a selfish person would not have been so eager to do more work than necessary.

Regardless, the results do suggest that money can inspire an aversion to social interaction and a focus on the self. In modicum, however, this may be a necessary part of a capitalistic society, where one is forced to place an emphasis on ensuring they are treated equitably and compensated fairly for their work—and where they are forced to compete for their livelihood. An interesting follow-up to this experiment would be to use neuroimaging to see what is going on in the brains of participants when they make decisions after exposure to money cues, and how it is different from controls.


Vohs, K.D., Mead, N.L., Goode, M.R. (2008). Merely Activating the Concept of Money Changes Personal and Interpersonal Behavior. Current Directions in Psychological Science, 17(3), (in press).

Who's the Decider?

It’s too bad Benjamin Libet didn’t live another year. If he did he would have been able to see the first neuroimaging evidence to support what he found with an electroencephalogram (EEG) almost thirty years ago: what we consider our conscious decisions are preceded by unconscious neural activity, which seems to be the actual—as President Bush would say—decider.

Libet conducted his most influential experiment involving neural activity and conscious decision-making at the University of California, San Francisco, in 1979. While he measured their brain activity with EEG, he asked participants to carry out a simple motor task (like pressing a button) at their own volition during a period of time. How many times and when they completed the task was up to the participant, but Libet asked them to note exactly when they felt they had made the conscious decision to make the movement. He found there was significant stereotypical neural activity that preceded the conscious decision-making, indicating there may be unconscious processes at work in choosing to execute a motor task.

Libet’s study sparked a great deal of controversy, as some saw it as a denunciation of free will. And rightly so, as Libet himself suggested the only evidence in support of free will is our own assertion that it exists. His experiments appeared to show unconscious brain activity that preceded conscious choice, making the entire concept of “conscious choice” questionable.

A study published in Nature Neuroscience this week adds more ammo to the materialist’s belt. A group of researchers in Germany conducted a study very similar to Libet’s, but used functional MRI (fMRI) to measure brain activity instead of EEG. They analyzed the images with computer software developed to recognize specific patterns of neural activity, in this case those that anticipated the participants’ decisions to press the button.

Not only did the group find neural activity that preceded conscious choice, but using the computer programs they were able to predict what choice the participant would make—up to 7 seconds before they “decided” they had made it. The predictions were not perfect, but much better than chance.

The researchers assert that this study doesn’t exclude the existence of free will. Even Libet maintained that there was a role for consciousness in decision-making, not in initiating an act, but in the ability to suppress it. The authors of this study agree, indicating that the capacity to reverse a decision made by the unconscious brain—something they plan to investigate in the future—would support a type of free will.

Libet died in July of last year, unfortunately less than a year before current brain scanning technology caught up with his theories of the late 1970s.