How Does EMDR Work? Exploring the Science

Eye Movement Desensitization and Reprocessing (EMDR therapy) is one of the most effective treatments for trauma and PTSD. Decades of research show that EMDR can help people process painful memories, reduce emotional distress, and move forward with their lives.

But a common question many people ask is: “How does EMDR actually work?”

While EMDR’s effectiveness is well established, researchers are still exploring exactly why it works. Several complementary theories shed light on the underlying mechanisms. Below, we break down the leading explanations behind this powerful therapy.

1. The Adaptive Information Processing (AIP) Model

The Adaptive Information Processing (AIP) model, developed by Francine Shapiro, is the foundational theory behind EMDR. It proposes that trauma can get “stuck” in the brain in a raw, unprocessed state, along with intense emotions, bodily sensations, and negative beliefs.

During EMDR therapy, clients focus on the traumatic memory while engaging in bilateral stimulation (such as eye movements, tapping, or alternating sounds). This process seems to activate the brain’s natural healing system, allowing the memory to be integrated into a wider, adaptive memory network. Over time, the memory becomes less emotionally charged and more fully part of the past

2. Working Memory Theory

Another well-researched explanation focuses on the brain’s working memory. When someone holds a traumatic memory in mind while simultaneously doing a demanding task (like following moving lights with their eyes), it taxes the brain’s working memory capacity. Because working memory is limited, both tasks can’t be vivid at the same time.

The result is that the traumatic memory becomes less vivid and emotionally intense. Multiple laboratory studies have demonstrated this effect, helping to explain why EMDR often leads to rapid reductions in emotional distress.

3. The Orienting Response

Bilateral stimulation may also activate an innate reflex called the orienting response. When we encounter a novel but safe stimulus, our nervous system first becomes alert, then shifts into a calmer, parasympathetic state once no threat is detected.

This calm but alert state helps people engage with difficult memories without becoming overwhelmed, making it easier for the brain to process traumatic material.

4. Interhemispheric Communication and REM-Like Processing

Some researchers suggest that EMDR increases communication between the brain’s hemispheres, similar to what happens during REM sleep—a phase where emotional memories are naturally integrated. EMDR’s side-to-side eye movements may activate similar neural pathways, supporting emotional integration and memory reconsolidation.

5. Memory Reconsolidation

When a memory is recalled, it enters a temporary “flexible” state. If new information is introduced during this time, the brain can update and reconsolidate the memory in a less distressing form. EMDR leverages this process by reactivating the traumatic memory in a safe therapeutic environment, paired with bilateral stimulation. The brain then stores the memory in a more adaptive, less emotionally charged way.

6. Exposure and Common Therapeutic Factors

Some early researchers believed EMDR worked primarily like traditional exposure therapy: repeated safe exposure leads to habituation. While exposure likely plays a role, studies show that EMDR’s eye movement component provides unique benefits—often speeding up processing and reducing emotional intensity faster than exposure alone.

As with all therapies, the therapeutic relationship, sense of safety, and client expectations also support the healing process.

Bringing It All Together

Most researchers agree that EMDR works through a combination of mechanisms:

• 🔹 Bilateral stimulation reduces emotional intensity and creates a state of calm focus.

• 🔹 Memory reconsolidation allows old memories to be updated with new, adaptive information.

• 🔹 Neural processes similar to REM sleep support integration.

• 🔹 A safe therapeutic relationship enables clients to revisit painful experiences without becoming overwhelmed.

The result is that traumatic memories lose their emotional charge, new insights emerge, and healing happens in a natural and lasting way.

Thinking About EMDR Therapy?

If you’re curious about EMDR therapy or wondering whether it might help you process trauma or difficult life experiences, consider reaching out for a consultation. EMDR is a structured, evidence-based approach that helps the brain do what it’s designed to do: heal.

👉 Book a consultation or learn more about EMDR therapy.