Relationship value and economic value are evaluated by the same part of the brain

Maybe this is the most important research study of the week—or the month.

Wishing a friend happy birthday or spending a long period of time listening to their problems signifies commitment to the friendship. In other words, these actions serve as commitment signals and it is known that people value their relationships more with others who behave this way towards them. This much has been known for some time.

Now researchers from several universities have revealed that the orbitofrontal cortex, the part of the brain responsible for calculating economic value, is also responsible for judging the value of relationships with friends based on the received commitment signals.

These findings were published in Social Neuroscience.

The researchers investigated whether valuable friendships and valuable objects are processed differently or in the same manner in the brain. The results suggest that relationship value and economic value are calculated in the same way, which is a surprise to most researchers in the field.

Many people feel happy when their friends spend time with them and pay attention to them; this makes them consider the relationship to be important. This is true even if the other person’s actions do not give profitable results. For example, if someone listens to your worries, this will strengthen your sense of the friendship’s importance, even if they were unable to resolve the problem.

The research team investigated which part of the brain is responsible for judging the value of relationships with other people according to information indicating the other person’s commitment to the relationship (commitment signals).

In order to identify which part of the brain judges the value of relationships with other people, the researchers had a total of 22 male and female participants in their twenties react to differing situations  while measuring their brain function using fMRI scans. Participants were given a total of 30 variations on the situations with a specific friend, and they were asked to imagine that each situation happened separately.

For example, one of the situations involves having a meal with a friend on your birthday. This situation was divided into three commitment signal conditions: “High-Cost Signal,” “Low-Cost Signal” and “Signal Failure.” In the “High-Cost Signal” variation, the friend bought you dinner for your birthday (which costs the friend economically). In the “Low-Cost Signal” variation, the friend only wished you happy birthday (which does not cost the friend economically) and in the “Signal Failure” scenario, the friend did not mention your birthday. There were 10 situations, each with 3 conditions (“High-Cost Signal,” “Low-Cost Signal” and “Signal Failure”) making for a total of 30 scenarios. Participants repeatedly evaluated on a scale of 0 (weak) to 100 (strong) as to whether their friend’s behavior in each scenario would strengthen or weaken their relationship.

The experiment results revealed high levels of activity in the part of the brain known as the orbitofrontal cortex. The orbitofrontal cortex was most active during the “High-Cost Signal” scenarios, whereas activity was weakest during the “Signal Failure” scenarios.

It is known the orbitofrontal cortex also calculates economic value. For example, in one study by a different research group, hungry participants were presented with various snacks and told that they could actually buy and eat them after the experiment. They were then asked to evaluate how much money they would be willing to pay for them. In this experiment, the participants’ brains assigned value to the snacks and the orbitofrontal cortex was active during their evaluation.

The results from the current study suggest that the brain automatically judges and re-evaluates relationship value upon receiving a commitment signal from a friend, in the same way that it responded in the experiment where participants were given snacks.

So, what? This study helps to confirm what we and other researchers have been saying for a long time—that relationships are central to the whole of the human system. In a sense our judgement of economic value is a subset of our evaluation of the relational support that will come from making what seems to be an economic or utilitarian choice.

To use their example of the snacks, the amount we are prepared to spend on the snacks may seem related to our hunger and little else but what we and others have found is that even these mundane economic choices mask other, more fundamental relationship issues.

Most obviously, for example, we may have in mind that our partner is afraid of our gaining weight through sugary snacks. If the relational choices and the economic choices are both processed by the same parts of the brain, then it adds weight (excuse the pun) to the notion that the motivation between the two is also the same.