Why Can Bilateral Stimulation Use Eyes, Sounds, or Tapping?

Why Can Bilateral Stimulation Use Eyes, Sounds, or Tapping?

Short Answer: Eye Movement Desensitization and Reprocessing (EMDR) can use different forms of bilateral stimulation because the stimulation can be delivered through more than one sense. You might follow something moving from side to side with your eyes, listen to sounds alternating between the left and right ears, or use alternating taps on the left and right sides of the body. These methods all give you another task to attend to while briefly focusing on a memory, thought, feeling, or sensation. Researchers are still studying exactly why this part of EMDR helps, and the different forms should not be assumed to work identically. One leading explanation is that dividing attention between the memory and another task places demands on working memory, which may make a distressing memory feel less vivid or emotionally intense.

Key Takeaways

• Bilateral stimulation can be visual, auditory, or tactile.
• Eye movements usually involve following something from side to side.
• Auditory stimulation may use sounds that alternate between the left and right ears.
• Tactile stimulation may involve alternating taps on the left and right sides of the body.
• These methods give your attention something else to do while you briefly focus on distressing material.
• Researchers do not yet have one definitive explanation for exactly how bilateral stimulation contributes to EMDR.
• Eye movements have been studied more extensively, so it should not be assumed that every type of stimulation produces exactly the same effects.

What Is Bilateral Stimulation?

“Bilateral” simply means involving two sides.

In EMDR, bilateral stimulation usually involves a repeated pattern that moves or alternates from one side to the other. Depending on the method, that might involve your vision, hearing, or sense of touch.

Common examples include:

• Eye movements: Following a visual target as it moves from left to right and back again.
• Alternating sounds: Hearing tones or other sounds alternate between the left and right ears.
• Tapping: Alternating taps between the left and right sides of the body.

The form of stimulation can change, but the broader EMDR process still involves briefly bringing something to mind while simultaneously attending to another task.

Why Aren't Eye Movements the Only Option?

Eye movements were part of the development of EMDR and remain one of its best-known features. But researchers and clinicians have also explored other tasks that divide attention while a person recalls a distressing memory.

This is important because one major theory of how EMDR works focuses less on the eyes themselves and more on working memory.

Working memory is the limited mental workspace you use to hold and work with information for a short period. For example, you use working memory when remembering a phone number long enough to type it or when keeping part of a sentence in mind while reading the rest.

Recalling a vivid memory uses some of this limited capacity. Following moving objects with your eyes or doing another attention-demanding task also uses mental resources. Some people may use EMDR to work with memories or experiences connected to stress.

According to the working-memory explanation, doing both at once creates competition for those resources. As a result, the memory may temporarily become less vivid or emotionally intense while it is being recalled. Research has provided meaningful support for this explanation, although scientists are still investigating EMDR's full mechanism of action.

How Do Eye Movements Work?

During visual bilateral stimulation, you typically follow a moving target with your eyes while keeping your head relatively still.

Your attention is divided between the memory or other focus and the visual task.

Laboratory studies have repeatedly found that making eye movements while recalling unpleasant memories can reduce ratings of how vivid or emotionally intense those memories feel. This is one reason the working-memory explanation has received considerable research attention.

Exactly what happens during a complete course of EMDR is more complicated than simply making a memory less vivid, however. EMDR includes multiple phases and involves much more than bilateral stimulation alone.

How Do Alternating Sounds Work?

Auditory bilateral stimulation uses sound instead of a moving visual target.

For example, a tone may alternate between the left and right ears through headphones. You listen to that pattern while also briefly focusing on the memory, thought, feeling, or sensation being addressed.

Sounds provide another task for your attention without requiring you to track something visually.

Research has found that alternating tones can affect recollections, although some studies have found stronger effects from eye movements. One study comparing eye movements and alternating beeps found that both affected negative memories, but eye movements produced larger effects in that experiment.

That is why it would be too simple to say that sounds and eye movements are scientifically interchangeable in every respect.

How Does Tapping Work?

Tapping uses touch rather than sight or hearing.

A person may alternate taps between the left and right sides of the body—for example, tapping one side and then the other in a repeating pattern.

This provides a physical task to notice while attention is also directed toward the material being processed.

Like sounds and eye movements, tapping is one way of creating the divided or dual attention used during EMDR. Research into exactly how different attention tasks compare is continuing, and there is not yet one complete explanation that accounts for every effect seen during EMDR.

Does the Stimulation Have to Alternate Left and Right?

Alternating from side to side is a traditional feature of bilateral stimulation, but research has raised an interesting question about whether the left-right pattern itself is the most important part.

Some experimental findings suggest that the mental demands of performing a second task while recalling a memory may matter more than whether that task specifically alternates between the two sides of the body.

For example, research on the working-memory explanation has found effects from attention-demanding tasks that are not necessarily dependent on horizontal left-right stimulation.

So although “bilateral stimulation” remains the familiar term used in EMDR, researchers continue to study which features of the stimulation actually contribute to its effects.

Are Eyes, Sounds, and Tapping Equally Effective?

Research does not currently support a simple statement that every form works exactly equally well.

Eye movements have received substantial research attention. Some experiments comparing eye movements with sounds have found stronger effects for eye movements, while other findings suggest that several kinds of dual-attention tasks can affect memory vividness or emotional intensity.

Individual preference can also matter in practice. Someone may find it easier to follow a visual target, while another person may prefer listening to alternating sounds or using tactile stimulation.

The important distinction is that having several available methods does not mean researchers have proven them to be identical.

Bilateral Stimulation Is Only One Part of EMDR

Because eye movements are so visually recognizable, they sometimes receive most of the attention when people describe EMDR.

But EMDR is not simply “moving your eyes while thinking about something upsetting.”

It is a structured process that can involve identifying what you want to work on, noticing thoughts and emotions connected with it, using periods of bilateral stimulation, checking what comes up, and continuing through a series of steps.

Bilateral stimulation is one component within that larger process. EMDR may also be used when past experiences are connected to anxiety or distressing reactions.

Bilateral Stimulation in Self-Guided EMDR

Bilateral stimulation can also be provided in online and self-guided EMDR formats.

With the Virtual EMDR self-guided program, for example, the bilateral stimulation is built into the online experience, and users can select and adjust available stimulation settings themselves. This reflects the same broader principle: bilateral stimulation does not have to be delivered by someone physically moving their hand in front of you.

Whether EMDR is done with a therapist, remotely, or through a structured self-guided format, visual, auditory, or tactile methods can be used to provide the additional focus of attention associated with EMDR.

Conclusion

Bilateral stimulation can use eyes, sounds, or tapping because EMDR does not depend on only one sensory method for providing an additional focus of attention.

Eye movements use vision, alternating sounds use hearing, and tapping uses touch. Each gives your attention another task while you briefly focus on a memory, thought, feeling, or sensation.

Researchers are still working out exactly why this process contributes to EMDR. One of the leading explanations is that recalling a memory while doing another attention-demanding task places competing demands on working memory, which can change how vivid or emotionally intense the memory feels.

That does not mean every form of bilateral stimulation works identically. Eye movements have been studied more extensively, and research comparing different methods is still developing. The broader takeaway is that EMDR can use more than one sensory pathway to create the divided attention that is part of the process.