Imagine you’re not long out of bed. Groggy, you’re looking forward to your morning coffee. However, as you take your first sip, it tastes a bit odd, a
bit off. Your brain is already at work, registering that small mismatch between what it expected and what it found in that first sip of coffee. That small moment of “this isn’t quite what I thought” is what neuroscientists call a prediction error.

Prediction errors are how we learn about the world, notes neuroscientist Dr Camilla Nord in her book The Balanced Brain: The Science of Mental Health. When things turn out better than expected, the brain releases a burst of dopamine, strengthening the link between that action and its reward. When they turn out worse, dopamine activity drops, and the brain quietly files the experience under “avoid next time.” The brain is always adjusting its expectations, whether it relates to that first cup of coffee in the morning or to the larger swings of life. For the most part, it’s an efficient learning system. It teaches us where to find food, who to trust, what to steer clear of. It also shapes our emotional world and how we feel about life itself.

Some people are more attuned to the small shifts when things go better than expected. Others, through temperament or experience, learn more quickly from disappointment. “Cumulatively, over many years of learning, these small differences in the way your brain learns might make you expect better or worse outcomes and begin to build a general perception of the world as a good or bad place,” writes Dr Nord. When the mind stays open to small, pleasant surprises, life can feel a little easier to approach. However, when your brain is tuned to expect disappointment, it keeps finding evidence for it.

For example, depression often dulls the brain’s response to positive surprises. Someone might have a nice meeting with an old friend, or get unexpectedly good news, or achieve a small success at work, or some such positive surprise. However, it may not feel as rewarding as it would for someone else. The brain may not register the learning signal properly, often because the person dismisses small improvements or sees them as flukes rather than real evidence that things can go well. Similarly, the anxious mind often fails to revise its fears when things go fine. One frightening experience can teach the brain to be over-vigilant and over-predict threat. The anxious mind often expects the worst and discounts evidence when things go well. Each calm outcome should create a prediction error – a moment of “it wasn’t as bad as I thought” – but the brain fails to update and revise its expectations. Instead, it discounts the new evidence (“I got away with it this time”) and holds on to the earlier sense of threat.

This is why CBT (cognitive behavioural therapy) often focuses on behavioural experiments: to help the brain notice when expectations are wrong, reduce unhelpful thinking patterns like discounting, and promote new learning. When someone faces a feared situation in a controlled way – speaking up in a meeting, touching a supposedly “contaminated” surface, going out to a café alone – they are running a behavioural experiment. The outcome is rarely as bad as predicted, and the brain learns something new. Gradually, those small “it wasn’t as bad as I thought” moments start to change what the person expects next time. The same principle applies to low mood. CBT places much emphasis on behavioural activation: that is, encouraging people to get involved in everyday activities that could lift their mood, even if they don’t feel like it at first. Often someone begins an activity thinking, “I’m not in the mood, this is pointless”, and only afterwards realises, “Actually, I do feel a bit better.” Each pleasant surprise – each positive prediction error – helps rebuild the sense that effort and reward are intertwined.

It’s a biological process as much as a psychological one. Dopamine cells fire when the world violates our pessimism in a good way, nudging us to revise our internal model. That’s why progress often feels slow but steady. The brain is literally relearning what to expect. This framework also helps explain why self-criticism or avoidance can be so persistent. If we never test our expectations, we never generate new learning signals. The anxious person who avoids social contact, or the depressed person who stops trying, deprives the brain of opportunities to be pleasantly
surprised. Being wrong, basically, is how the brain keeps adapting. Every unexpected kindness, every feared outcome that fails to materialise, is a neurological opportunity. Our brains are not fixed. In that sense, recovery is less about positive thinking and more about giving the brain fresh evidence that the world can still surprise you.

Linda Hamilton is a Kinsale-based cognitive behavioural therapist. If you would like to get in touch with her, call 086-3300807 For more information, go to www.kinsalecbt.com