The Neurobiology of Attachment

Many people are already familiar with attachment theory and its significance in how we relate to ourselves and others. Are we anxiously attached, desiring closeness to co-regulate? Are we avoidantly attached, preferring space to recharge and tending to feel emotions less intensely than our anxiously attached partners? Or perhaps we have a disorganized attachment style due to lots of early adversity and caregivers who felt unsafe or inconsistent.

But what is the neurobiology of attachment, and why is it especially important for clients with complex trauma?

Before going further, a gentle reminder: if anything you read in this article begins to feel overwhelming and you need to pause, please listen to that signal and return later. Discussions of attachment can activate old wounds for clients with complex trauma, particularly when they recognize aspects of themselves in what they’re reading. This can lead to emotional flooding, spacing out, numbness, rumination, or other nervous system responses. Listen to your body’s cues and take a break if needed.

To begin, let’s talk a bit about attachment itself. What do babies need in order to develop a healthy, secure sense of self?

First and foremost, they need a felt sense of safety, love, and play within their relationship with their mother. Babies need to experience their caregiver’s love, curiosity about them, responsiveness to distress, respect for their need for space when calming down, and the caregiver’s ability to repair moments of misattunement during interaction and play.

As a side note, attachment researcher Ed Tronick found that even in secure attachment relationships, caregivers are misattuned to their babies about 70% of the time. What distinguishes secure attachment is not perfect attunement, but the caregiver’s ability to notice misattunement and repair it quickly and reliably. Through this process, the baby learns, “Even if I’m not perfectly understood right now, this rupture can be repaired.” This experience builds relational safety and resilience, strengthens self-confidence, and fosters a more positive view of self and world.

Tragically, many babies do not receive this experience for a variety of reasons. Environmental stressors such as poverty, limited access to medical care, and exposure to crime can negatively impact the infant–caregiver dyad. Babies who are adopted—even into loving homes—are still profoundly affected by the loss of their original caregiver to whom they were attaching. Babies whose caregivers have anxious, avoidant, or disorganized attachment styles themselves are also likely to be impacted by those patterns.

There are many factors that can disrupt a baby’s ability to bond and experience co-regulation, and these disruptions are felt at a neurobiological level. Importantly, the neurobiological imprints of early attachment disruptions remain with us into adulthood. They can be accessed and healed in therapies that pay close attention to how attachment wounds show up in the body—through sensations, posture, and nervous system states.

Here’s an example.

Imagine a mother and baby interacting. The baby needs to calm her nervous system by briefly breaking eye contact. The baby looks away, but instead of maintaining her distance and allowing the baby to regulate, the mother moves closer in an effort to re-engage. This makes it harder for the baby to calm down, as the mother is now encroaching on the baby’s space.

In response, the baby may turn her head further away to create more distance. If the mother continues to pursue the baby’s attention, the baby might turn her head sharply to the side—perhaps even to a 90-degree angle. If the mother still does not back off and instead looms over the baby, the baby may eventually slump forward into a collapse posture, with her head hanging down. This posture finally prevents further intrusion by the mother and allows the baby’s nervous system to downregulate.

If this pattern occurs frequently—if the baby repeatedly has to collapse in order to feel safe—the baby may begin to develop a neurobiology characterized by emotional dampening and a need for distance to regulate. As an adult, this may show up as difficulty feeling emotions, challenges with shame or confidence, trouble connecting to others, or feeling voiceless in relationships.

This is just one example of how disruptions in the attachment bond can shape neurobiology and later impact emotional regulation, relationships with self and others, the ability to understand others’ inner emotional worlds, and resilience in the face of adversity.

If a baby develops an anxious attachment style, their neurobiology will feature sympathetic nervous system activation during relational distress—such as a racing heart, surges of adrenaline, increased muscle tension, and faster speech. Conversely, an avoidant attachment style will have parasympathetic hypoarousal, including depression, emotional numbness, low energy, and feeling spacey or shut down, difficulties taking in the emotions of others, and a tendency to isolate in order to calm.

Clients with complex trauma often experience both patterns and may even feel them simultaneously. For example, they might notice tightness in the chest and throat while their arms go limp and lose muscle tone.

Equally important is helping clients notice the interplay between somatic sensations and the head–body relationship. A client might recall seeing a cold expression cross their partner’s face and notice nausea in their stomach alongside a turning away of the head. Another client may feel anxiety in the chest, bracing in the shoulders, followed by a sinking sensation in the stomach as they debate whether to say something their partner may not like. Or a client feeling criticized by their boss might feel a shiver down the spine, a hollowing in the stomach, and then a slumping of the head and shoulders into a collapse posture, accompanied by coldness or loss of muscle tone in the arms.

These are all examples of how attachment wounds live in the body and emerge in present-day relationships. We do not need to remember what it was like to be babies or young children in order to heal. Instead we need only bring mindful attention to our current relational experiences, in the presence of an attuned therapist who can help us track and regulate these patterns safely.