A habit of trust
It is a familiar tale: you have a friend who takes up with a partner that you suspect may have links to the criminal underworld or, worse still, has no fashion sense and an alarming liking for One Direction. You counsel the friend as gently as possible that this may not be a wise choice of partner but love is blind and they persist with the relationship despite your wise intervention. The couple stay together for a few years, to your bemusement, and then it happens; that partner you never really liked cheats on your friend. You are dismayed at your friendâ€™s pain but glad to see the back of the â€œnever-was-any-goodâ€ ex. The upside is that you and your friend can now resume spending more time together, until â€¦ you get the phone call saying that they have forgiven their partner their indiscretion and they are back together. You feign happiness but secretly wonder how your friend can accept such treatment. Now you need wonder no more because new research has shown what goes on in the brain when this kind of thing happens.
In the study, researchers had subjects take part in a game with a partner that was actually a computer, although the subjects thought it was another person. In the game the subject was given some money and was allowed to choose whether to share it with their partner or keep it to themselves. If they shared it, the value would triple and the â€œpartnerâ€ would then have the choice to either keep all of the money or share it evenly with the subject. Sometimes the â€œpartnerâ€ (the computer) would betray the subject early in the game and keep all the money and for other subjects the computer would wait until late in the game before betraying.
Not surprisingly, if a person was betrayed early in the game they were then more likely to keep the money to themselves as the game went on. By contrast, if the betrayal came later, after more of a relationship had been established, then the subjects were more likely to forgive and continue sharing. What was interesting though was what showed up on MRI scans of the subjectsâ€™ brain activity.
The scans showed that when a person was betrayed early in the game there was a lot of activity in a part of the brain called the anterior cingulate cortex, which is involved in learning, planning and problem solving. There was also activity in the lateral frontal cortex, an area involved in uncertainty. Activity in these areas was not so pronounced when the betrayal came later, after more of a relationship had been established. When the betrayal came later there was more activity in the lateral temporal cortex, an area involved in habitual decision making.
So it seems that once you have an established relationship with someone, you make up your mind about that relationship and are less likely to learn new things about the relationship and to engage in solving problems arising from those new things. These findings apply to romantic relationships as we described earlier but they could also apply to the workplace where long-term co-workers are more likely to be forgiven errors than a new body in the office.
As far as your friend who is taking appalling treatment from that despicable partner is concerned, at least you know there is a biological underpinning for their behaviour. Perhaps you could try saying, â€œCome on! Get out of your lateral temporal cortex, fire up your anterior cingulate cortex and leave that jerk!â€ Your friend may have no idea what you are talking about but at least youâ€™ll have had a chance to parade your superior knowledge of brain physiology.