Can Bilateral Stimulation Be Too Slow?

Can Bilateral Stimulation Be Too Slow?

Short Answer: Bilateral stimulation can be slow enough that it demands very little attention, but there is no universal speed that is officially “too slow.” In Eye Movement Desensitization and Reprocessing (EMDR), the stimulation is meant to give your attention a second task while you also focus on a memory, thought, feeling, image, or body sensation. Research suggests that faster eye movements generally place greater demands on working memory and can produce stronger effects on memory vividness and emotionality than slower movements. However, slower stimulation can still be used, and the appropriate pace can vary depending on the person, the type of stimulation, and the part of the session.

Key Takeaways

• There is no universal minimum speed for bilateral stimulation.
• Slower stimulation can still be used during EMDR.
• Faster eye movements generally place greater demands on attention and working memory.
• If the stimulation becomes extremely easy to ignore, it may provide less of a dual-attention task.
• Slower does not automatically mean ineffective.
• The useful pace can vary between people and from one session to another.

What Would “Too Slow” Mean in EMDR?

Bilateral stimulation can involve:

• Following a visual target from side to side
• Listening to alternating sounds
• Feeling alternating taps or pulses

Each method can be delivered at different speeds.

There is no single number below which bilateral stimulation suddenly stops being useful.

Instead, “too slow” is better understood in practical terms.

If the stimulation is moving so slowly that it barely requires your attention, it may create less competition for the mental resources you are also using to recall the memory.

That matters because one leading explanation for EMDR involves a dual-attention task: you focus on the memory while simultaneously doing something else that requires attention.

Why Does Attention Matter?

One well-supported explanation for the effects of eye movements involves working memory.

Working memory is the limited mental space you use to temporarily hold and work with information.

Remembering a vivid event requires some of those resources. Following a moving target also requires attention.

When you do both at once, the tasks compete for limited working-memory capacity.

Experimental studies have found that both slower and faster eye movements can reduce ratings of memory vividness and emotional intensity compared with simply recalling the memory. However, the more demanding faster movements have often produced larger effects.

This suggests that the amount of attention required by the stimulation may matter.

Does That Mean Slow Bilateral Stimulation Does Not Work?

No.

Research does not support such a simple conclusion.

In one experimental study, slower eye movements produced effects that generally fell between faster eye movements and recalling the memory without eye movements. The faster condition produced the strongest effects, but the slower condition was not equivalent to doing nothing.

Another study found that eye movements reduced memory vividness and emotionality regardless of speed, although greater cognitive load tended to produce larger effects.

So it would be inaccurate to say that bilateral stimulation must be fast to have any effect.

Why Might Faster Eye Movements Have a Stronger Effect?

Faster eye movements are generally more demanding to follow.

Imagine tracking a dot that moves slowly across the screen. The task may require some attention, but it may become fairly easy.

Now imagine the same dot moving much faster.

You need to devote more attention to keeping track of it.

Research suggests that this greater demand places more strain on working memory. When the memory and eye-movement task compete for those limited resources, the recalled image may become less vivid or emotionally intense.

That helps explain why researchers have found stronger effects from faster eye movements in some experiments.

Why Not Always Use the Fastest Possible Speed?

Because greater difficulty is not automatically better.

The task still needs to allow you to do two things at once:

follow the bilateral stimulation + stay connected to the material being processed

If the stimulation becomes so fast that nearly all your attention goes toward following it, that can interfere with the balance of the dual-attention task.

The goal is therefore not maximum speed.

It is an attention-demanding but workable pace.

Research has also tested whether eye-movement speed should be precisely matched to each person's working-memory capacity. That prediction was not supported, which means science has not produced a formula for calculating one ideal speed for each person.

Is There a Minimum Recommended Speed?

There is no universal scientifically established minimum.

Research studies often use fixed speeds so different experimental conditions can be compared.

For example, one study compared slower eye movements at about 0.8 cycles per second with faster movements at about 1.2 cycles per second. The faster movements produced larger changes in memory ratings.

Those numbers are research conditions, not universal rules for EMDR sessions.

They should not be interpreted as meaning that anything below a particular number is automatically too slow.

How Can You Tell if Visual Stimulation Feels Very Slow?

A slow pace may feel like:

• The target is extremely easy to follow
• Your eyes spend noticeable time waiting for the target to move
• The movement requires almost no concentration
• Your attention easily drifts away from the visual task

None of these automatically means the session is ineffective.

But if the stimulation is intended to create an attention-demanding task and it requires almost no attention, increasing the speed may make the task more engaging.

Can Slower Bilateral Stimulation Still Be Appropriate?

Yes.

There are several reasons the pace may be slower at one point than another.

For example:

• A slower setting may simply be easier to follow.
• A different part of the EMDR process may use a different pace.
• A person may need time to become familiar with the stimulation.
• The form of bilateral stimulation may have changed.

The appropriate speed can also change during the same session.

There is no requirement that every set use exactly the same pace.

Can the Speed Change as Processing Continues?

Yes.

EMDR processing can shift from one set to the next.

You might begin with a vivid image and later notice:

• A different thought
• Another memory
• A new emotion
• A body sensation
• A less vivid version of the original memory

As the focus changes, the stimulation may also be adjusted.

This is why speed is better understood as one adjustable part of EMDR rather than a fixed setting that must remain unchanged.

Can the Same Slow Speed Feel Different From Session to Session?

Yes.

The same setting may require more attention one day and less attention another day.

Your experience can also depend on what you are processing.

A vivid or absorbing memory may compete differently for your attention than a memory that already feels less vivid.

Research has found individual differences in responses to working-memory tasks, although attempts to precisely match eye-movement speed to measured working-memory capacity have not shown a clear advantage.

So variation between sessions is not unusual.

What About Auditory Bilateral Stimulation?

Alternating sounds can also be slower or faster.

However, auditory stimulation and eye movements do not necessarily place identical demands on working memory.

One experimental study found that eye movements taxed working memory more strongly than alternating beeps and also produced larger reductions in memory vividness under the conditions tested.

That means a speed that seems relatively slow for visual stimulation cannot automatically be compared with the same numerical pace in auditory stimulation.

They are different sensory tasks.

What About Tactile Bilateral Stimulation?

Tapping and alternating tactile pulses can also vary in speed.

Again, there is no single minimum rhythm that everyone must use.

Research on tactile and vibratory bilateral stimulation is less extensive than the research on eye movements. A 2026 experimental study found that vibratory bilateral stimulation influenced the emotional response to negative autobiographical memories, and stronger distraction by the vibration was associated with greater reductions in emotionality.

That finding also fits the broader idea that how much attention the task captures may be important.

Does Slower Mean More Relaxing?

It may feel that way to some people, but that is not a universal rule.

A slower rhythm can feel easier or less attention-demanding.

However, EMDR bilateral stimulation should not automatically be described as a relaxation technique. During reprocessing, its role is connected to the dual-attention task while you focus on the material being worked on.

How calming, neutral, or demanding the stimulation feels can vary from person to person.

The material you are processing may sometimes be connected with anxiety, depending on your experience.

Does Slow Stimulation Mean the Session Is Not Working?

No.

Speed alone cannot tell you whether an EMDR session is productive.

A more useful question is what happens to the material being processed.

For example:

• Does the image change?
• Does a different thought appear?
• Does an emotion shift?
• Does another memory come up?
• Does a body sensation change?
• Does the original memory feel different after several sets?

Bilateral stimulation is only one part of the larger EMDR process.

Its speed should not be treated as a score for how successful the session is.

What About Slow Stimulation in Self-Guided EMDR?

Speed can also be adjusted in online and self-guided EMDR.

With the Virtual EMDR self-guided program, users manage their own pacing and can adjust available bilateral stimulation settings themselves.

This means you do not necessarily need to keep the same speed for every session.

A useful setting is one that you can follow while remaining engaged with the memory, thought, feeling, image, or body sensation you are working on.

The goal is not to find the slowest or fastest possible setting, but a workable level of attention demand. Some people may also be working with memories or experiences connected with PTSD.

Conclusion

Bilateral stimulation can become slow enough that it places very little demand on attention, but there is no universal speed that scientists have defined as “too slow.”

Research suggests that faster eye movements generally tax working memory more strongly and can produce larger changes in memory vividness and emotionality than slower movements. But slower eye movements can still have effects, and speed is only one part of the EMDR process.

The practical goal is not to make bilateral stimulation as fast as possible—or to avoid slower settings.

It is to use an attention-demanding but manageable pace that allows you to follow the stimulation while staying connected to the material you are processing.