Sleep Training Doesn't Create Calm. It Creates Shutdown.

I want to talk about something that tends to get flattened, oversimplified, or turned into a heated debate: sleep training.

Not as a parenting philosophy. Not as a moral issue. Not as a referendum on whether parents are “doing it right.”

But as a nervous system event.

Because when we zoom out of ideology and zoom into physiology, a different picture starts to emerge.

Sleep training is often framed as teaching babies how to self-soothe, but from an autonomic nervous system perspective, something else happens.

When a baby repeatedly signals distress and no one comes, the nervous system doesn’t “learn independence.” It adapts for survival.

And survival physiology is not optimized for emotional flourishing, relational depth, or long-term integration. It is optimized for getting through.

In some babies, that adaptation looks like shutdown.

Not panic.
Not chaos.
Not dysregulation that screams for attention.

Shutdown is quiet. It is the appearance of calm. Shutdown is not distress. It’s absence.

From an autonomic lens, shutdown is a conservation state. It’s marked by:

• reduced movement

• reduced vocalization

• reduced signaling

• reduced variability

In other words, less.

This is why shutdown is so often misunderstood. The baby doesn’t look “worse.” They look quieter. “Easier”. More compliant. Convenient, even, in a Western capitalistic framework.

Sometimes they even look like they’re sleeping better.

But behavioral quiet is not the same thing as physiological regulation.

And this distinction matters more than we’ve been willing to admit (or perhaps more than we’re aware).

One of the most cited studies in this conversation comes from Middlemiss et al. (2012), who looked at babies undergoing extinction-based sleep training.

What they found was uncomfortable. The babies stopped crying, but their cortisol — a marker of physiological stress — remained elevated.

Meanwhile, caregivers’ cortisol decreased. So yes, from the outside, it appeared as though the system had settled. But internally, the baby’s nervous system was still under strain.

The behavior changed. The physiology did not.

This pattern aligns with what we already understand from decades of autonomic and developmental neuroscience: when distress signals repeatedly go unanswered, some nervous systems don’t escalate.

They shutdown. They conserve. That’s not pathology. That’s not parenting philosophy. That’s biology.

Infants are exquisitely adaptive. They don’t ask, “What’s biologically ideal right now?!”. They don’t even have the wiring from their prefrontal cortex to their survival brain to posit such questions about their circumstances.

Their survival brains do however evaluate what is available.

If crying brings connection, crying continues. If crying brings nothing, crying is metabolically expensive. So the signaling stops.

This is not independence. It’s shutdown. (I apologize for repeating myself 100x here, but I am intentionally running the risk of belaboring the point because we are profoundly confused culturally).

And once you understand what’s really happening in a baby’s developing nervous system, a lot of things start to make sense, like how some babies seem “easy” but flat.

Or why quiet doesn’t always come with relaxation.
Or why stillness can coexist with tension.

Or perhaps even why you are operating from a perpetual state of low-grade disassociation yourself after being sleep-trained as a baby.

I want to be very clear here: I have no interest in wasting my precious time and energy pointing fingers at parents.

Most parents are doing the absolute best they can inside systems that offer very little support and a lot of pressure. Systems of supremacy. Of oppression.

This is about accuracy. It’s about awareness.

Because when we mistake shutdown for regulation, we misunderstand what babies are actually learning — especially at night, when attachment circuitry is still active.

Before I close, I wanted to share something I see over and over again in my work with families repairing from sleep training.

When responsiveness returns — when presence becomes reliable again — the nervous system doesn’t immediately get quieter. It gets louder.

More waking. More protest. More need. More reach.

Parents are often told this means something is wrong — that they should “stay the course” and continue to remove responsiveness at night.

It doesn’t mean any of those things. It means the nervous system is unthawing.

Sensation is returning. Signaling is coming back online.

That’s not regression. That’s capacity returning.

This is the sentence I wish we taught everywhere. This is what I wish I could pay to have plastered on a billboard on the 405, in Times Square, or on the front page of whatever news Apple promotes automatically on our iphones.

Quiet does not equal calm. Stillness does not equal safety.

Babies are wired from birth to regulate with us, not in isolation.

This isn’t ideology. It isn’t attachment theory gone rogue. It isn’t a parenting trend.

It’s just how survival physiology works.

I know there are skeptics who want citations stacked like a barricade.

I’ve shared many over the years, and I’ll continue to do so (a few below, for starters).

But I’m not interested in compressing the culmination of my life’s work into an Instagram comment section so that someone can scroll, skim, and feel “reassured.”

If this resonates — if something in your body recognizes this — isn’t that enough? Isn’t that the work of our lifetime as humans walking the path of remembering what we always knew? Isn’t that how we can move firmly from our societal sickness back into wellness?

It is from our hearts — not our heads — that we will remember what our babies need day and night.

You can explore my work, my courses, and my practitioner trainings here.

We don’t need to harden babies to make them sleep. We need to understand what their nervous systems are actually asking for.

And we need to be brave enough to listen.

A few sources for further reading, bearing in mind that there are interdisciplinary bodies of work covering this conclusion, not necessary single studies:

Wendy Middlemiss et al. (2012). Infant sleep training: Behavioral modification and physiological stress. Early Human Development, 88(4).

Stephen Porges (2011). The Polyvagal Theory. (Explore his entire body of work — idk how to summarize this in an IG slide).

Allan Schore (2001; 2012). Affect Regulation and the Origin of the Self; The Development of the Unconscious Mind.

Megan Gunnar & Donzella (2002). Social regulation of cortisol levels in early human development. Psychoneuroendocrinology.

Bruce Perry (2006). Applying principles of neurodevelopment to clinical work with traumatized children (explains how chronic stress can lead to down-regulation and conservation states rather than mobilization).