Behavioural experiments in CBT
Behavioural experiments are powerful drivers of change. They are a CBT strategy that we can use to formally test negative thoughts and predictions that patients hold that maintain their anxiety, depression, among other psychological problems.
For example, a person with social anxiety might have the thoughts that “I shouldn’t talk to them. They’ll think I’m a bother and not want to talk to me”. Another example might be a depressed patient, who may have the thought that “Why bother talking a walk? It’s not going to make me feel any better anyways.”.
As you can see, both these individuals have a specific prediction (they won’t respond kindly, engaging in activities won’t help my mood), which may be a maintaining factor for their psychological challenges. Behavioural experiments allow us to take the role of a curious scientist and test these predictions!
I have often used behavioural experiments in my own practice. For example, I have worked with perinatal women who have had anxieties about taking care of their baby. They may have a prediction that “if I let my partner take the baby for a bath, then the baby will cry and be very distressed”. This is a type of prediction that we can tackle through a behavioural experiment. Let’s see exactly what would happen if your partner took the baby for a bath while you stayed in the living room! Unsurprisingly, dad did just as well with the baby even without mom present (though we will talk about what happens in cases where a behavioural experiment doesn’t go as planned – which can be very informative as well).
Below, I talk about how to start conducting behavioural experiments with your own patients!
Benefits of behavioural experiments
There are several benefits to using behavioural experiments, which I’ll list below:
1. Behavioural experiments allow us to test a belief that could be maintaining a psychological challenge (e.g., anxiety/low mood). For example, “if I try something new, I won’t like it”.
2. Behavioural experiments reduce judgment and perfectionism because we are simply curious scientists. We make a hypothesis, and we simply see what happens without judgment.
3. Behavioural experiments therefore give us real-world evidence of whether our negative predictions are true or not. In the case that the prediction is not true, then we break through the vicious cycle and generate momentum to continue moving towards our goals.
4. Even in cases where a negative prediction comes true, that’s useful information too! Because we have evidence in ability to cope with negative events. Consequently, behavioural experiments 1) test whether a prediction is likely to be true and 2) whether we can cope even in cases where the negative prediction happens.
Components of working through a behavioural experiment with a patient
In behavioural experiments, there are a several steps you can guide the patient in working on to develop and complete a behavioural experiment
What’s the thought and anxious prediction. When creating a behavioural experiment, it is important to understand the scary thought or prediction in order to test it. For example, the anxious prediction of the post-partum mother was that the baby would cry and be very upset if her husband took them to the bath instead of her.
Rate the emotions and their intensity. Afterwards, check in with the patient what emotions they are experiencing in response to this idea from a scale of 0-100 (e.g., anxiety, 80%)
Develop the experiment. We develop experiments based on the prediction. For example, in this case the experiment might be “letting my husband take the baby for a bath in the evening while I sit in the living room”.
Write down what actually happened. The patient would then conduct the experiment and jot down what actually happened. In this case of the prediction being true, then they would write how did they cope? In this case, it might be that “the baby ended up crying, but husband was able to give the baby a bath. I came in afterwards to soothe the baby and we got her to sleep. It wasn’t exactly to plan, but we survived!”.
Reflect on the learning after the experience. The patient is also given space to jot down what they learned after the experience. Perhaps that their negative predictions were not true. Or it might be that their predictions were true, but they managed to get through it and it was not as catastrophic as they initially thought. You can also re-rate the emotions.
What if the patient does not do the experiment because it was too scary?
Sometimes, you may have to troubleshoot instances where the patient was too afraid to try out the prediction. In this case, you could use a SMART goals approach to work a goal that is more realistic and achievable at this time. For example, if the task is improving tolerance to uncertainty, then starting with something easy, like trying out a new restaurant rather than going straight into highly uncertain situations. It may also help to apply relaxation strategies or emotion regulation strategies to reduce anxiety enough to try out the experiment.

An example of developing a behavioural experiment with a patient
Below, I provide an example of developing a behavioural experiment with a patient with social anxiety.
Therapist: Ryan, I understand that you are interested in becoming more comfortable in social situations. I wonder if you would be interested in being a curious scientist with me and developing a test to see whether your anxious predictions are true?
Patient: Well, that sounds interesting. But I’m very worried about what other people would think or how they would react if I were to just talk to people in the streets.
Therapist: What would you think they would do if you said hello?
Patient: Well, I would imagine they would just look at me like I’m a weirdo, get angry at me, or ignore me.
Therapist: It sounds like you already have a prediction that we could test! If I say hello to strangers, they will ignore me or get angry at me. Is that right?
Patient: Yes, I’m quite sure of it.
Therapist: I wonder if that could be our behavioural experiment then. Over the next week, to talk to at least one person a day and write down what happened for each one.
Patient: That sounds pretty scary. I’m not sure if I can do it.
Therapist: It definitely sounds pretty scary! To do something so scary, the juice needs to be worth the squeeze. Any reason you think this might be helpful for your social anxiety?
Patient: Well, it’d be really nice if I could start doing this because I would probably be a lot more comfortable in social situations. I might also start being able to make friends or strike up more conversations at work.
Therapist: Do you think it’s worth it to put yourself in uncomfortable situations like this to be able to move towards those goals?
Patient: Yeah, I guess it’s worth a try.
Therapist: Fantastic! And we can think of this like you are just a curious scientist, experimenting to see whether your prediction is true or not. As scientists, we are non-judgmental and simply observant in the data. This way of thinking may be helpful to remove yourself from the situation. In this experiment, just smile and say hello and see what happens!
Patients: Sounds good, I’ll give it a try this week.
Concluding thoughts
I hope this post was helpful in learning how to develop behavioural experiments with patients! Behavioural experiments are fantastic ways to test our anxious beliefs using behavioural strategies rather than a thought record. I find the evidence from behavioural experiments can often be stronger than thought records, since we see real-world evidence of our anxious thoughts being less likely to happen than we first thought. Patients thoughts are often more unrealistic than they think, and their resilience is often higher than they think!
If you found this this article helpful, please consider subscribing to the mailing list for more evidence-based information on mental health!
Best wishes,
P