Are Eye Movements Necessary for EMDR to Work?
Eye Movement Desensitization and Reprocessing (EMDR) is best known for one unusual feature: while a person brings a distressing memory to mind, they also follow a side-to-side visual stimulus, usually the therapist’s fingers or another moving target.
That naturally raises a question: Are the eye movements actually necessary for EMDR to work, or would the treatment work just as well without them?
Researchers have studied this question for decades, and the answer has changed as the evidence has developed.
Some early studies and reviews concluded that eye movements did not add anything important to the treatment. Later research, including laboratory studies, clinical trials, and meta-analyses, found evidence that eye movements can make distressing memories less vivid and less emotionally intense and may contribute something beyond memory recall alone.
The most accurate conclusion today is that eye movements appear to contribute to at least some of EMDR’s effects, but they are not the whole treatment and researchers have not established that every successful EMDR outcome depends specifically on eye movements.
Why Have Eye Movements Been So Controversial?
EMDR is a complete psychological treatment, not simply a technique involving moving the eyes.
During EMDR, a person identifies a distressing memory and aspects associated with it, such as thoughts, emotions, physical sensations, and beliefs. The memory is then processed while a form of bilateral stimulation is used.
Eye movements are the most common form of this stimulation, but other forms, such as alternating taps or tones, are also sometimes used.
The controversy developed because researchers wanted to know whether the eye movements themselves were an active ingredient in the treatment.
In other words:
Would people improve just as much if they went through the rest of the EMDR procedure but kept their eyes still?
Studies designed to answer that question are sometimes called dismantling studies because researchers remove one component from a treatment and see whether the results change.
What Did Early Dismantling Studies Find?
Some of the earliest dismantling studies did not find a clear advantage for eye movements.
A 1994 trial involving 23 people with Post-Traumatic Stress Disorder (PTSD) compared three versions of a treatment related to EMDR:
standard eye movements;
eye movements produced by tracking a light; and
fixed visual attention without eye movements.
All three groups improved, and researchers found no significant differences among them. They concluded that the eye movements did not appear essential to the treatment outcomes in that small study. (PubMed)
A 2001 meta-analysis reviewing 34 EMDR studies also reported no significant additional benefit from eye movements when EMDR was compared with similar procedures without them.
The authors concluded that the available evidence at that time did not support the necessity of the eye-movement component. (PubMed)
These findings contributed substantially to early skepticism about why EMDR worked.
However, research continued.
What Did Later Research Find?
Later studies began producing a different picture.
A 2013 meta-analysis specifically examined whether eye movements contributed something measurable when people processed distressing memories.
Researchers separated the evidence into:
clinical treatment studies comparing EMDR with eye movements against EMDR without them; and
laboratory studies comparing memory recall with and without eye movements.
The analysis included 15 clinical trials and 11 laboratory studies, with 849 participants overall.
In the clinical studies, adding eye movements produced a moderate and statistically significant additional effect. In the laboratory studies, the effect was larger.
The strongest difference involved reductions in the vividness of distressing memories. (PubMed)
This challenged the earlier conclusion that eye movements were simply unnecessary.
What Do Eye Movements Seem to Do to Memories?
One of the most consistent findings from experimental research is that eye movements performed while recalling a distressing memory can change how that memory is experienced.
In particular, studies have found reductions in:
memory vividness;
emotional intensity; and
subjective distress associated with the memory.
These effects fit with one of the leading explanations for EMDR, known as the working-memory theory.
Working memory is the limited mental system used to hold and manipulate information temporarily.
Recalling a vivid emotional memory requires some of that mental capacity. Following a moving visual target also requires attention and mental resources.
When both happen at the same time, the theory proposes that they compete for the same limited capacity. As a result, the memory may become harder to hold in its original vivid and emotionally intense form.
A 2022 systematic review found evidence supporting this general mechanism: recalling distressing material while performing a secondary working-memory task tended to reduce memory vividness and emotional intensity compared with recalling the memory alone. (PubMed)
For a more detailed explanation of this theory, see What Is the Working-Memory Theory of EMDR?
Does That Mean Eye Movements Are the Special Ingredient?
Not necessarily.
Working-memory research raises an important distinction.
If the benefit occurs because the brain is trying to do two demanding things at once, then eye movements may not be the only possible way to create that effect.
Other tasks that require attention can also compete with memory recall.
Researchers have therefore studied alternatives such as:
alternating taps;
auditory tones;
counting tasks;
other visual tasks; and
different forms of bilateral stimulation.
Some of these also appear capable of reducing memory vividness or emotional intensity under experimental conditions.
That suggests the important mechanism may involve dual attention or working-memory taxation, rather than a unique biological effect that can occur only when the eyes move from side to side.
This issue is examined more directly in Eye Movements, Tapping or Tones: What Has Research Actually Studied?
What Did a Larger Clinical Trial Find?
A 2016 randomized clinical trial examined this question in 139 people with PTSD.
Participants received a standard EMDR procedure but were assigned to different visual-attention conditions:
eye movements while following the therapist’s moving hand;
looking at the therapist’s stationary hand; or
exposure to the memory without a specified visual focus.
The purpose was to isolate the possible contribution of eye movements and dual attention while keeping the rest of the treatment as similar as possible. (PubMed)
The study did not produce a simple finding that eye movements alone determined whether treatment worked. Improvements occurred across conditions.
However, research of this kind is important because it helps separate the effects of the overall treatment protocol from the effects of one specific component.
This is also why researchers remain cautious about statements such as:
“Eye movements are definitely the reason EMDR works.”
The evidence does not support reducing the entire treatment to that one ingredient.
What Do Systematic Reviews Say?
A systematic review focused specifically on the role of eye movements concluded that clinical evidence had been mixed, while laboratory studies provided stronger support for their effects.
The review found theoretical and experimental support for the idea that eye movements may influence memory processing, particularly through effects on working memory and distress during memory recall. (PubMed)
A broader 2018 systematic review examined 87 studies investigating proposed EMDR mechanisms.
Researchers grouped the explanations into:
psychological mechanisms;
psychophysiological mechanisms; and
neurobiological mechanisms.
The review found reasonable support for working-memory explanations and for physiological changes during EMDR, while emphasizing that no single mechanism had been conclusively established. (PubMed)
This broader evidence suggests that asking whether eye movements are “necessary” may be slightly too simple.
A better question may be:
What contribution do eye movements or other dual-attention tasks make within the complete EMDR treatment?
Is Memory Recall Alone Enough?
Research comparing eye movements with memory retrieval alone is particularly useful.
If both groups recall the same distressing material, but one group also performs eye movements, differences between them can help researchers identify the additional effect of the eye movements.
Recent research has continued using this kind of design.
For example, a randomized study involving 91 adults with PTSD compared eye movement desensitization with a retrieval-only condition in which participants recalled traumatic material without making the same eye movements. Researchers examined cognitive and other treatment-related outcomes across follow-up periods. (PubMed)
Another study using the same general research program examined stress reactivity following eye movement desensitization compared with retrieval alone. (PubMed)
These studies reflect an important development in EMDR research: instead of asking only whether the complete treatment works, researchers are increasingly trying to understand what changes when eye movements are added to memory recall.
Do Eye Movements Have to Be Side to Side?
Not necessarily.
Standard EMDR commonly uses horizontal eye movements, but the underlying scientific explanations do not necessarily require one exact movement pattern.
If the working-memory explanation is correct, what may matter is that the secondary task is sufficiently demanding to compete with the mental resources used to hold the distressing memory in mind.
Researchers have therefore experimented with different speeds, directions, and alternative tasks.
This does not mean that any random distraction will work equally well.
The amount of working-memory demand appears to matter. A task that is too easy may have little effect, while one that is too demanding could interfere so much that the person cannot adequately keep the memory in mind.
Researchers are still studying how to balance those demands.
What About Tapping and Tones?
EMDR protocols can also use alternating tactile stimulation, such as tapping, or auditory stimulation, such as alternating tones.
The National Institute for Health and Care Excellence (NICE) describes EMDR as using repeated in-session bilateral stimulation, usually eye movements, but notes that other forms may also be used. (PubMed)
The fact that EMDR can be delivered with more than one form of bilateral stimulation is another reason the question cannot simply be reduced to whether side-to-side eye movements are absolutely indispensable.
Research generally provides the most extensive experimental evidence for eye movements, but alternative forms of stimulation have also been studied.
Whether they produce identical effects is a separate scientific question.
Do Eye Movements Explain All of EMDR's Effectiveness?
No.
Even research supporting eye movements does not imply that they explain the entire treatment.
EMDR includes multiple elements:
preparation;
identifying memories to work with;
bringing aspects of a memory to mind;
noticing thoughts and physical sensations;
bilateral stimulation;
repeated processing;
identifying more adaptive beliefs; and
reassessing the memory and its emotional impact.
The therapeutic relationship and the structured way the treatment is delivered may also matter.
The complete clinical effect of EMDR could therefore result from several processes acting together.
This is why evidence that eye movements have a measurable effect is different from evidence that eye movements alone are sufficient treatment.
No credible interpretation of the current evidence supports treating the eye movements by themselves as equivalent to the full EMDR protocol.
Why Did Older and Newer Studies Reach Different Conclusions?
Several factors may explain the changing evidence.
Early dismantling studies were often small.
Some included only a few dozen participants, making it difficult to detect modest differences between treatment conditions.
Researchers have also improved the way eye movements and treatment procedures are standardized and measured.
The 2013 meta-analysis found that treatment fidelity—how closely studies followed the intended procedure—affected the size of the eye-movement effect. (PubMed)
Laboratory research also became more sophisticated.
Instead of measuring only whether PTSD symptoms changed after an entire treatment program, researchers began directly measuring what happened to an individual memory when participants recalled it with and without eye movements.
Those experiments repeatedly found changes in vividness and emotional intensity.
So the scientific picture evolved because researchers began asking more precise questions.
Does EMDR Still Work If Eye Movements Are Not Used?
The evidence suggests that therapeutic improvement can occur when other forms of bilateral stimulation or dual-attention tasks are used.
It also shows that some early studies found improvement even when the eye-movement component was removed.
But that does not mean eye movements make no contribution.
The stronger current interpretation is that eye movements appear to have measurable effects on memory processing, while successful EMDR treatment probably depends on more than eye movements alone.
Researchers therefore distinguish between:
Are eye movements the entire treatment?
No.
Do eye movements appear to contribute something?
Current evidence suggests that they can.
Are eye movements absolutely required for every successful EMDR treatment?
Research has not established that.
That distinction captures the evidence more accurately than either extreme.
What Can We Reasonably Conclude?
The history of this research is important.
Early dismantling studies and reviews often found little evidence that eye movements added anything important to EMDR. (PubMed)
Later meta-analyses and experimental studies found that eye movements can produce measurable additional effects, particularly by reducing the vividness and emotional intensity of distressing memories. (PubMed)
Working-memory research provides one plausible explanation for those findings.
At the same time, EMDR is a complete treatment containing many elements. Research does not show that eye movements alone explain all of its clinical effects, and other forms of bilateral stimulation or dual-attention tasks may also contribute to memory processing.
The most accurate conclusion is therefore:
Eye movements appear to be an active part of EMDR rather than a meaningless addition, but the evidence does not show that side-to-side eye movements are the only possible way EMDR can work or that they alone account for the treatment's effectiveness.
Frequently Asked Questions
Are eye movements required in every EMDR session?
Not necessarily. Eye movements are the most common form of bilateral stimulation used in EMDR, but other forms such as alternating taps or tones may also be used.
Do eye movements actually change traumatic memories?
Research suggests that recalling a distressing memory while making eye movements can reduce its vividness and emotional intensity compared with recalling the memory alone. (PubMed)
Did research once suggest that eye movements were unnecessary?
Yes. Several early dismantling studies and reviews concluded that eye movements did not add a significant benefit. Later research using improved methods has produced stronger evidence that eye movements can make a measurable contribution. (PubMed)
Could tapping or tones work instead of eye movements?
Alternative forms of bilateral stimulation are used in EMDR and have also been studied. However, the research base is not identical for every form of stimulation, so it is difficult to say that all methods produce exactly the same effect.
Are eye movements the reason EMDR works?
They may be one part of the explanation. Research supports effects on working memory, memory vividness, emotional intensity, attention, and possibly other processes. EMDR also contains several treatment components beyond eye movements.
Conclusion
The question of whether eye movements are necessary for EMDR has been studied for decades.
Early research often suggested that they were not essential. Later and more targeted research has found evidence that eye movements can make distressing memories less vivid and less emotionally intense and can add measurable effects beyond simply recalling the memory.
The working-memory explanation currently provides one of the strongest scientific accounts of why that may happen.
But the evidence does not support reducing EMDR to eye movements alone.
Eye movements appear to contribute to memory processing during EMDR, while the treatment's overall effectiveness is likely to involve the interaction of several components. Whether eye movements themselves are absolutely indispensable in every successful form of EMDR remains an open scientific question.
