How brains measure self-esteem
How we feel about ourselves is largely dictated by what we think other people think of us. But just as important as someone else’s opinion is what we expect them to think of us. If we believe that someone should rate us highly and, in fact, they don’t, the dent to our confidence is much greater than a bad rating from someone we expect to mark us down. And Leiden University’s Geert-Jahn Will has identified where in the brain this happens…
Geert-Jahn - We know that our self-esteem is shaped by what other people think of us, but what we didn't know is how the brain keeps track of what other people think of us and then how this is integrated into our evaluation of our own worth. So we set out to study this. We asked healthy young people to perform a social evaluation task while they laid in an MRI scanner. And before they came to the lab they uploaded a personal profile to an online database and we told them that other people were going to look at this profile and that they were going to receive feedback from these people. And while they were in the scanner we showed them the feedback that they had received which actually was a computer algorithm so that we could control the feedback. And people received likes or dislikes in the forms of thumbs up and thumbs down symbols which represented whether the other person was interested to get to know them or whether they thought they were not so interesting. And then after every two or three judgments from these peers, they reported on their current level of self-esteem.
Chris - Now critically did they know about the likely judgment that the person was going to make or was the judgment completely blind to them?
Geert-Jahn - So what we were interested in is not just whether your self-esteem goes up and down. We were critically interested in expectations. So whether you expect to be liked by the other person and how that impacts how you feel about yourself when you received the feedback. The participants in our study interacted with different kinds of people which we subdivided into groups. We used these groups so that participants could learn whether some people were more likely or less likely to give positive feedback. And what we saw in the result is that participants started to expect to be liked by the people in the groups that mostly gave positive feedback and they started to expect to be disliked by those who were more likely to give negative feedback.
Chris - What about though how that impacts on their self-esteem. So if you say to someone you're going to get feedback from this person who usually, 90 percent of the time gives positive feedback but then you say actually they hated you. What does that do to their self-esteem?
Geert-Jahn - Yes, so that is exactly what we were interested in. What we saw is that when participants received a thumbs down by someone who is in general very positive, so when they expected to be like the most, their self-esteem went down the most and the opposite was also true. And we could quantify this sort of level of surprise using a mathematical model. What was sort of central to this mathematical model was prediction errors. They captured the difference between the feedback that you had expected to receive and the feedback you actually received. So we found that self-esteem changes were guided not only by whether other people like you but were especially dependent on whether you expected to be liked.
Chris - It's interesting this because we've all been there haven't we, we know that the professor of biochemistry is very hard to please, but when he or she gives us positive feedback we get a rush of self-esteem feeling very pleased with ourselves because we got feedback from a hard taskmaster.
Geert-Jahn - Exactly. So it seems very intuitive but what is the most innovative part of our study is that we can actually quantify these feelings using mathematical models. And this is important so that we can actually use the model to identify signals in the brain that sort of explain why our self-esteem goes up and down when we learn other people's judgments of us.
Chris - Yes indeed because you had these subjects in brain scanners while you were asking them to rate their esteem in response to this feedback. So what did you see? What was their brain doing in each case and how did that match up with how they were feeling about themselves?
Geert-Jahn - The mathematical model contains the prediction errors that people use to determine their self-esteem. And what we saw is that these prediction errors were tied to activity in parts of the brain that are very important for learning and valuation. And we could infer how people felt about themselves before they actually reported on how they felt. And we identified a signal in the ventral medial prefrontal cortex that sort of keeps track of how good you feel about yourself.
Chris - So is that where you see this going next? You now have this objective data showing our self-esteem centre in the prefrontal cortex. Could you now take that forward and so will let's look at certain psychiatric illnesses or problems of esteem and depression and see how those illnesses and also getting better from those illnesses are reflected in the behavior of these brain regions.
Geert-Jahn - Yes, so that is exactly the direction that I'm going in. We are currently looking at how these processes might be different in people with levels of self-esteem that are much lower. And then the next step would be to study this in people who suffer from psychiatric disorders such as depression. Ultimately I hope that we can use these insights to design new treatments or design new methods for diagnosis.