Behavioral Experiment (Portrait Format)

Behavioral experiments enable clients to test beliefs and achieve lasting changes through experiential learning.

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Offers theory, guidance, and prompts for mental health professionals. Downloads are in Fillable PDF format where appropriate.

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Overview

Behavioral experiments are integral to cognitive behavioral therapy (CBT), providing a structured framework for testing and re-evaluating beliefs. This resource guides clients in designing and conducting meaningful experiments, as well as reflecting on their learning.

Why Use This Resource?

Behavioral experiments are an effective way to achieve cognitive and behavioral change

Collaboratively test ideas and beliefs through bespoke experiments.
Encourage experiential learning by actively gathering relevant evidence.
Facilitate deeper cognitive changes active, multisensory tasks rather than discussion alone.

Key Benefits

Collaboration

Work with client to tests their beliefs.

Investigation

Collect real-world evidence to evaluate problematic cognitions.

Change

Encourage adaptation of new, more helpful beliefs.

Versatility

Utilize this tool with clients experiencing various difficulties.

Who is this for?

Panic Disorder

Engaging with feared stimuli or testing catastrophic predictions.

Social Anxiety

Testing beliefs around social fears such as rejection.

Low Self Esteem

Evaluating assumptions related to acceptability and self-worth.

Perfectionism

Engaging with beliefs about performance and performance-related behaviours (e.g., checking).

Eating disorders

Testing beliefs about eating feared foods or reducing appearance-focused behaviours.

Other Difficulties

Behavioural experiments are useful in treatments for other difficulties, including depression and PTSD.

Integrating it into your practice

Identify

Select a belief or assumption to be tested.

Design

Devise an experiment with clear hypotheses.

Conduct

Implement the experiment and collect relevant data.

Evaluate

Assess outcomes and compare to initial beliefs.

Refine

Use new insights to re-evaluate existing beliefs and inform future experiments.

Theoretical Background & Therapist Guidance

A key component of cognitive behavioral therapy (CBT), behavioral experiments are regarded as one of the most effective methods for bringing about cognitive change (Bennett-Levy et al., 2004). According to cognitive theories (e.g., Teasdale & Barnard, 1993), interventions that incorporate experiential learning are particularly effective at bringing about both head-level (intellectual) and heart-level (emotional) belief change, as well as creating new schematic models (Bennett-Levy et al., 2004). Some research supports these claims, indicating that behavioral experiments are more efficacious than some cognitive interventions (Bennett-Levy, 2003; McManus et al., 2011) and exposure (McMillan & Lee, 2010). However, studies directly exploring the effectiveness of behavioral experiments remain limited.

Behavioral experiments are defined as planned experiential activities that aim to generate new data. Depending on the goal of the task, data might be sought to test the validity of the client’s existing beliefs, develop or test more adaptive beliefs, or to inform a formulation or case conceptualization (Bennett-Levy et al., 2004). CBT therapists tend to use two types of behavioral experiment (Rouf et al., 2004; Kennerley et al., 2017):

Active experiments, in which the client does something to generate information. For instance, the client might experiment with assertive communication to establish whether this is more effective than passive communication.
Observational experiments, in which the client observes events or gathers existing data rather than doing something differently. For instance, the client might observe the therapist communicating assertively to see how others respond, or carry out a survey to gather factual information or opinions relevant to the client’s concerns.

Behavioral experiments can also be classified as either hypothesis-testing or discovery-oriented. Hypothesis-testing experiments are the most commonly used type in CBT and closely align with the scientific method, allowing clients and therapists to collaborate as co-investigators (Kennerley et al., 2016). They can be subdivided into three core forms (Rouf et al., 2004):

Testing hypothesis A – In this format, the client tests the accuracy of their existing (typically unhelpful) belief. For example, a person with social anxiety might believe “If I blush in public, people will think I’m weird.” A hypothesis A experiment might involve deliberately provoking blushing (e.g., applying makeup) and observing other people's reactions.
Comparing hypotheses A and B – This involves evaluating two competing explanations: the original dysfunctional belief (hypothesis A) and a new, potentially more helpful one (hypothesis B). A client who believes, “If I make a mistake at work, I’ll be fired” might be encouraged to test both this and an alternative hypothesis such as, “If I make a mistake, my manager will provide constructive feedback.”
Testing hypothesis B – This focuses on actively gathering evidence to support a new belief. For instance, a client developing a new belief like “Most people are friendly” might be asked to initiate small interactions (e.g., asking for directions) and record other people's responses to strengthen their belief through direct experience.

When the client does not have a clear hypothesis to test (e.g., when their negative cognition hasn't been articulated) or they are unsure of what might happen if they were to behave differently, discovery-oriented experiments are typically used (Rouf et al., 2004). These experiments are more exploratory and open-ended than hypothesis-testing experiments (e.g., "I don't know I'd feel or what other people would do if I said 'thank you' in response to a compliment - let's find out") (Kennerley et al., 2016).

Rouf and colleagues (2004) have outlined other important considerations for planning and conducting effective behavioral experiments:

Clarifying the purpose and rationale: Ensure the goal of the experiment is clear and aligned with the client’s therapeutic objectives.
Targetting specific cognitions: Identify and rate (0-100%) the negative automatic thought, assumption, or core belief the will be tested to establish a measurable baseline.
Considering the setting and resources needed: Identify a suitable setting for the experiment (e.g., within session or in the real world) and the resources needed, as well as potential challenges and relevant solutions.
Aiming for ‘no-lose’ outcomes: Design experiments where any result will yield helpful learning.
Incorporating worksheets. Use worksheets to track predictions, outcomes, and emotional changes.

Equally important is helping clients make sense of behavioural experiments (Rouf et al., 2004). Key considerations when evaluating the outcomes of experiments include:

Allowing time for thorough discussion: Dedicate sufficient time to reflect thoroughly, ensuring all learning is extracted from the experience.
Guided discovery: Use questions to explore what the experiment reveals about the situation, self, others, and strategies for managing distress.
Linking outcomes to existing knowledge: Connect findings to original predictions, target cognitions, and the formulation to assess their validity or need for adjustment.
Incorporating client feedback: Encourage clients to summarize what they learned and explore any doubts to identify persistent unhelpful perspectives.
Strengthening new learning: Reinforce insights through ongoing reflection, written summaries, or follow-up experiments.

This Behavioral Experiment (Portrait Format) worksheet guides you through the essential steps required to plan, implement, and evaluate the outcome of behavioral experiments. It is well suited for hypothesis testing / planned experiments ("If I do X then Y will happen") but can be equally useful for data gatheing ("If I ask X then I will learn Y").

What's inside

Step-by-step guidance on devising, conducting, and evaluating behavioral experiments with clients.
Easy-to-use framework for recording beliefs, predictions, and outcomes.
Suggestions helping clients plan and reflect on their experiments.

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FAQs

A behavioral experiment is a structured exercise that involves gathering data to test the validity of a belief.

While exposure therapy focuses on habituation to reduce fear responses, behavioral experiments emphasize testing specific beliefs through data collection.

Begin with smaller in-session experiments or carry out experiments that the client observes to build confidence.

Discuss alternative explanations and design follow-up experiments that either confirm or disconfirm the initial findings.

How This Resource Improves Clinical Outcomes

By integrating behavioral experiments into therapy, these tasks can help:

Modify unhelpful beliefs and assumptions.
Reduce problematic behaviors, such as avoidance.
Support collaboration through co-designed therapeutic tasks.

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References And Further Reading

Beck, A. T., Rush, A. J., Shaw, B. F., & Emery, G. (1979). Cognitive therapy of depression. Guilford Press.
Bennett-Levy, J., et al. (2004). The Oxford handbook of behavioural experiments. Oxford University Press.
Bennett–Levy, J. (2003). Mechanisms of change in cognitive therapy. Behavioural and Cognitive Psychotherapy, 31, 261–77.
Chadwick, P. D. J., et al. (1996). Cognitive therapy for delusions, voices and paranoia. Wiley.
Craske, M. G., et al. (2014). Maximizing exposure therapy. Behaviour Research and Therapy, 58, 10-23.
Herbert, E. A., & Dugas, M. J. (2018). Behavioral experiments for intolerance of uncertainty. Cognitive and Behavioral Practice, 26(2), 421-436.
Kennerly, H., Kirk, J., & Westbrook, D. (2017). An introduction to cognitive behaviour therapy: Skills and applications (3rd ed.). Sage.
Kolb, D. (1984). Experiential learning. Prentice Hall.
Rouf, K., Fennell, M. J. V., Westbrook, D., Cooper, M., & Bennett-Levy, J. (2004). Devising effective behavioural experiments. In J. Bennett-Levy, G. Butler, M. Fennell, A. Hackmann, M. Mueller, & D. Westbrook (Eds.), Oxford guide to behavioural experiments in cognitive therapy (pp. 21-58). Oxford University Press.
Salkovskis, P. M. (1991). The importance of behavior in the maintenance of anxiety. Behavioural Psychotherapy, 19, 6–19.
Waller, G. (2009). Evidence-based treatment and therapist drift. Behavior Research and Therapy, 47, 119e127.

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