“Leaves on a Stream” – Cognitive Defusion Exercise

Acceptance and Commitment Therapy (ACT)GoodTherapy | “Leaves on a Steam” – Cognitive Defusion Exercise provides us with the tools to practice cognitive defusion, which is the willingness to let go of the attachment and over-identification with thoughts that cause suffering. When fusion to thoughts becomes problematic, those thoughts become “true” and “real” in ways that prevent us from engaging in workable action and living according to chosen values. Essentially, cognitive fusion serves to keep us “stuck” in problematic patterns of thinking that lead to same old inevitable consequences: emotional suffering.

It doesn’t have to be this way. Cognitive defusion is a tool that, when mindfully and diligently practiced, serves to disentangle you from thoughts that cause you to suffer. The first step is to recognize that you are the observer of your thoughts, not the thoughts themselves. You are the eternal and mindful presence that is capable of noticing your thoughts entering into conscious awareness, sitting in the forefront of your awareness, and then leaving awareness.

The way to begin to free yourself from unnecessary emotional suffering begins with your willingness to look at your thoughts in a new way. If your patterns of thinking or negative self-talk tends to cause you significant emotional distress, begin to ask yourself how willing you are to try to consider those thoughts differently. Rather than choose to become “caught up” in negative thinking to the point where you lose perspective, begin to let go of your attachment to that negative thinking.

Cognitive Defusion Exercise

Harris (2009) provides an excellent cognitive defusion exercise used in Acceptance & Commitment Therapy:

“Leaves on a Stream” Exercise

  1. Sit in a comfortable position and either close your eyes or rest them gently on a fixed spot in the room.
  2. Visualize yourself sitting beside a gently flowing stream with leaves floating along the surface of the water. Pause for 10 seconds.
  3. For the next few minutes, take each thought that enters your mind and place it on a leaf… let it float by. Do this with each thought – pleasurable, painful, or neutral. Even if you have joyous or enthusiastic thoughts, place them on a leaf and let them float by.
  4. If your thoughts momentarily stop, continue to watch the stream. Sooner or later, your thoughts will start up again. Pause for 20 seconds.
  5. Allow the stream to flow at its own pace. Don’t try to speed it up and rush your thoughts along. You’re not trying to rush the leaves along or “get rid” of your thoughts. You are allowing them to come and go at their own pace.
  6. If your mind says “This is dumb,” “I’m bored,” or “I’m not doing this right” place those thoughts on leaves, too, and let them pass. Pause for 20 seconds.
  7. If a leaf gets stuck, allow it to hang around until it’s ready to float by. If the thought comes up again, watch it float by another time. Pause for 20 seconds.
  8. If a difficult or painful feeling arises, simply acknowledge it. Say to yourself, “I notice myself having a feeling of boredom/impatience/frustration.” Place those thoughts on leaves and allow them to float along.
  9. From time to time, your thoughts may hook you and distract you from being fully present in this exercise. This is normal. As soon as you realize that you have become sidetracked, gently bring your attention back to the visualization exercise.

What was it like for you to engage in this brief cognitive defusion visualization exercise? Be patient and compassionate with yourself if you found yourself struggling to remain fully present and mindful. This is natural. Begin to reframe any difficulties that you may have encountered during this visualization exercise as opportunities for growth. Cognitive defusion is a tool that takes practice to become skilled. The potential reward of choosing to engage in regular mindful awareness and cognitive defusion is the ultimate freedom from the unnecessary suffering of maladaptive thoughts. Loosen their grip on you and choose to become the mindful observer.



Harris, R. (2009). ACT made simple. Oakland, CA: New Harbinger Publications, Inc.

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  • Mary

    February 12th, 2024 at 5:24 PM

    Extremely helpful article. Clearly explained. It provokes visual imagery for me just as the exercise does.

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