Leaves on a Stream: An ACT Defusion Meditation for Watching Your Thoughts Pass
Leaves on a Stream is an ACT cognitive defusion exercise that uses imagined leaves to practice observing thoughts, so you can choose how to respond when worries hold your attention.
Reviewed by Jack Bartel, PsyD 
About this tool
Leaves on a Stream is a guided ACT exercise for observing thoughts as passing mental events. It offers a way to practice stepping back when worry or self-criticism captures your attention, then deciding what to do next. Leaves on a Stream is one of the best known exercises in Acceptance and Commitment Therapy, used to teach cognitive defusion: the skill of stepping back from your thoughts so they have less grip on you. Instead of arguing with a thought or trying to push it away, you practice noticing it as a passing mental event, something the mind produces, rather than a command you must obey or a truth you must believe.
The exercise asks you to picture a gently flowing stream with leaves drifting on the surface. As each thought arises, you place it on a leaf and watch it float away. You do not force the leaves to move faster, and you do not try to stop the stream. When you notice you have been hooked by a thought and have stopped watching, that noticing is the exercise working: you gently return to the bank and resume placing thoughts on leaves.
Defusion does not make thoughts disappear, and it is not a relaxation technique, though people often feel calmer afterward. The point is a shift in relationship: seeing that you are the one observing your thoughts, not the thoughts themselves. With practice, this loosens the automatic pull of self-critical, anxious, or repetitive thinking, freeing you to act on your values instead of your mind's running commentary.
Defusion techniques like this one sit inside a broader body of ACT research. A meta-analysis of controlled trials found that ACT performs about as well as established treatments such as cognitive behavioral therapy for anxiety and depression, and clearly better than no treatment or treatment as usual (A-Tjak et al., 2015). Leaves on a Stream is usually taught as one tool among several rather than a stand-alone treatment, so it works best paired with values work or committed action when you are using it for a specific problem. This review evaluated ACT treatment programs across mental and physical health problems. It does not establish that this particular meditation alone treats anxiety or depression, and finding no significant difference from established treatments does not prove that all approaches are interchangeable.
If a thought keeps returning with intense distress, or the exercise leaves you feeling numb or disconnected rather than gently observing, stop and bring that to a therapist trained in ACT instead of pushing through alone. Our therapist directory at /therapist/ lets you search by specialty at no cost.
Use the reflection prompts to describe what happened without grading your performance. For example, you might write, "I kept returning to a worry about work, then noticed I could hear the room again." Repeated thoughts and an unchanged mood do not give this exercise a failing score. Look for whether you noticed a thought and had room to choose your next action.
After practicing, choose an action connected to something you care about, such as returning to a conversation or preparing a meal. The Committed Action Plan Worksheet can help make that choice concrete. The ACT Worksheets Library offers related exercises, and the Anxiety Test can support a separate discussion of symptoms with a clinician; the reflection notes here are not a screening score.
References
- Hayes SC, Strosahl KD, Wilson KG. Acceptance and Commitment Therapy: The Process and Practice of Mindful Change. 2nd ed. Guilford Press; 2012.
- Harris R. The Happiness Trap. 2nd ed. Trumpeter; 2022.
- A-Tjak JGL, Davis ML, Morina N, Powers MB, Smits JAJ, Emmelkamp PMG. A meta-analysis of the efficacy of acceptance and commitment therapy for clinically relevant mental and physical health problems. Psychother Psychosom. 2015;84(1):30-36.
- A-Tjak JGL et al. Abstract and study details for the ACT efficacy meta-analysis cited above. PubMed. https://pubmed.ncbi.nlm.nih.gov/25547522/
Cite this source
Psychology.com. (2026, September 16). Leaves on a Stream. Psychology.com. https://psychology.com/tools/leaves-on-a-stream
Leaves on a Stream FAQ
What is the Leaves on a Stream exercise for?
Leaves on a Stream teaches cognitive defusion, an ACT skill for noticing thoughts without automatically following them. The exercise invites you to place thoughts on imagined leaves and observe what happens. Its purpose is to practice choosing your response when thoughts feel convincing or distracting; relief is not guaranteed during a particular practice.
What if I keep getting distracted?
That is the exercise, not a failure. Each time you notice you have been hooked and gently return to the stream, you are practicing the exact skill ACT is trying to build. You can include the thought "I am distracted" on a leaf as well. There is no need to restart the whole script or keep a tally of interruptions.
Is this a relaxation technique?
Not exactly. People often feel calmer, but the goal is a change in your relationship with your thoughts, not relaxation. Treat the calm as a welcome side effect, not the target. If you finish with the same feeling, reflect on whether you noticed your thoughts differently. Avoid forcing the imagery to produce calm.
Is my information saved?
No. Everything stays in your browser. Your entries are never uploaded or stored, and the PDF is generated on your own device.
How long should I practice Leaves on a Stream?
Choose a brief practice that feels manageable and leaves room to reflect afterward. There is no required duration or guaranteed point when you will feel a shift. You can return to the exercise when it is useful, while watching whether practice supports daily activity or becomes another effort to force unwanted thoughts away.
Does cognitive defusion help with anxiety and intrusive thoughts?
Defusion is one of the core skills taught in Acceptance and Commitment Therapy for anxiety, and research on ACT overall shows it performs comparably to established treatments like CBT. Leaves on a Stream will not stop intrusive thoughts from arising, but it can reduce how much they hook your attention and drive what you do next. That evidence concerns ACT programs rather than this exercise alone, so persistent distress deserves an individualized clinical assessment.