How Our Brains Adapt to Trust and Betrayal

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Carrie Steckl earned her Ph.D. in Counseling Psychology with a Minor in Gerontology from Indiana University – Bloomington in 2001. She has spent over ...Read More

I was only a kindergartener the first time I was betrayed. No, I didn’t already have a boyfriend at the tender age of four. But I did have schoolmates as part of my first social universe.

I was sitting next to one of them during snack time, and he offered me his chocolate chip cookie for my oatmeal bar. I agreed, thinking that this was a fair trade and feeling pretty excited about getting to eat chocolate at ten in the morning.


But it was not meant to be. After giving him my oatmeal bar first, he giggled as he took both the bar and the cookie and shoved them in his mouth. Hence my first experience of betrayal.

No matter how many good choices we think we make, betrayal is a part of life. Luckily, so is trust. And if we can figure out who to trust in our personal and professional lives, then even when we run across the untrustworthy, we can continue to function within a healthy support system. Feeling mentally drained by overthinking? Take our online overthinking quiz to assess the impact of overthinking on your overall mental well-being.

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I recently read about an interesting study in London that explored how the brain adapted to cooperative (trustworthy) social encounters as well as untrustworthy ones (betrayals). Using functional magnetic resonance imaging (fMRI), the researchers found that cooperation and betrayal in social exchanges led to unique patterns of brain activity. Specifically, when we encounter unexpected cooperation from someone, we adapt our behavior more than when we encounter unanticipated betrayal. Also, as we engage in more and more social exchanges, our brain reacts less and less to untrustworthy people.

Hmmm…this sounds to me like our brain is learning! Excellent. In other words (and the authors came to this conclusion, too), as the number of people we meet in life continues to rise, untrustworthy and uncooperative behavior becomes less surprising. On a related note, cooperative behavior is appreciated more over time and is rewarded by pro-social behavior.


I think the most interesting finding of the study was that over time, our brains adapt in such a way that it is optimized to cooperate with trustworthy people rather than optimized to avoid those who might betray us. It’s as if we focus on the trustworthy, knowing that this will, in turn, naturally shield us from betrayal.

Think about the network of friends you’ve developed over time. Was it a process of identifying those whom you could really trust and weeding out those you couldn’t? Probably. Now think about your cohort of colleagues at work. Are there certain people you enjoy working with more than others? Are there those that you seek out because you know they are people of integrity? Sure.

In a way, the research is poignant in that it illuminates that there is a lot of disappointment in this world through the conduit of betrayal. But the shining light of the study is that our brain is adapting to this reality, even if we don’t realize it, so that we can ultimately choose trustworthy people to be in our lives.

And maybe – just maybe – that learning will help us make sure that our chocolate chip cookies never get stolen from us again.


Smith-Collins, A.P.R., Fiorentini, C., Kessler, E., Boyd, H., Roberts, F., & Skuse, D.H. (2012). Specific neural correlates of successful learning and adaptation during social exchanges. Social, Cognitive, and Affective Neuroscience, doi: 10.1093/scan/nss079.

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