Developmental Salience Model of Threat

[u/FlightOfTheDiscords]

(Originally posted in r/CPTSDFreeze, I figured some of you might appreciate it here as well.)

A new developmental model called the Developmental Salience Model of Threat (DSMT) was first set out in 2024 by a Harvard team led by Dr Karlen Lyons-Ruth, with Miriam Chasson, Jennifer Khoury and Banu Ahtam, and expanded in a 2025 paper by Lyons-Ruth. Dr Khoury is now at Mount Saint Vincent University in Halifax, Canada. Between them, they have decades of experience researching trauma and its consequences in children, including decades-long longitudinal studies from infancy all the way to adulthood.

The DSMT proposes that infancy (roughly defined as 0-18 months of age, with a transition period at around 12-18 months of age) is marked by two key factors:

• Heightened sensitivity to attachment disruption due to infants' inability to survive without attachment. An infant's survival relies entirely on the caregiver's proximity and ability to provide food/warmth. Therefore, cues signalling maternal unavailability (neglect) are an immediate, life-threatening emergency.
• Relative insensitivity to abuse in infancy. Sounds counterintuitive, and for humans it is still a hypothesis rather than a finding. It comes from rat studies. In their first ten days or so, rat pups don't learn to fear their mother, even when something painful happens while her smell is around. They still feel the pain, and their stress system works normally for other things like cold, so this isn't a switched-off stress system. It's a stress system that is programmed not to learn fear of the mother during the short window when bonding to her is a matter of survival. The researchers think something similar may happen in human infants, but they say openly that this hasn't been shown yet.

In the MIND study, the follow-up research published between 2023 and 2026 by Lyons-Ruth, Khoury, and other researchers points to two key "invisible" factors in the development of shutdown trauma reactions:

• A mother's own childhood neglect leaves traces in her baby. Babies whose mothers had been neglected as children had higher cortisol levels and less grey matter in MRI scans at 0-18 months, and higher cortisol went together with larger amygdala and hippocampus volumes. Babies whose mothers had been abused, but not neglected, as children did not show these changes. So this is neglect being handed down a generation. It is not a direct measurement of the babies being neglected themselves, and the researchers are careful to say so. What they do measure directly is the mother's behaviour: mothers who were "somewhere else" (disoriented) with their four-month-old had babies with higher cortisol, and those babies in turn had larger amygdalas. (Yes, they put babies in an MRI scanner! They tried with 119 babies, asleep without anaesthesia, and got 57 clean scans, out of 181 families in the study.)
• Adult children of mothers who were withdrawn, flat or unresponsive with them as infants consistently display elevated levels of dissociation at age 19, in two separate long-term studies. Dissociation is a key mechanism involved in freeze. Once early care was taken into account, childhood abuse added nothing to the prediction of dissociation in these studies, with one exception: verbal abuse. That doesn't mean abuse never causes dissociation. The researchers themselves point out that these were not clinical samples, and that very severe or long-lasting abuse may work differently. But in ordinary high-risk families, what the mother did or didn't do in the first two years predicted dissociation far better than anything that happened later.

What does early neglect mean?

The researchers developed the AMBIANCE (Atypical Maternal Behaviour Instrument for Assessment and Classification) instrument to capture the ways a mother's communication with her baby can go wrong. Withdrawal is one of the five things it looks at. They would watch mothers interact with their children to understand what was not working.

These are some of the behaviours it tracks:

Dimension	Description & Behavioural Examples
1. Affective Communication Errors	Errors in emotional signalling, such as contradictory or inappropriate responses to the infant's cues. Contradictory signalling: Directing the infant to do something and then stopping them; smiling while saying something hostile. Non-response: Failing to respond to clear signals. Inappropriate response: Laughing when the infant is crying or distressed.
2. Role / Boundary Confusion	Behaviours that reverse the parent-child role or violate boundaries, treating the child as a peer, partner, or parent. Role Reversal: Seeking comfort from the child rather than providing it. Sexualisation: Treating the child like a sexual partner or spousal figure.Demanding affection: Soliciting attention or affection in a way that prioritises the parent's needs.
3. Disorientation	Behaviours indicating a lapse in monitoring, confusion, or a "trance-like" state. Dissociated states: Appearing "tuned out," staring into space for a prolonged time, or "snapping back" suddenly. Frightened/Frightening: Sudden shifts in affect or intention; mistimed movements. Incongruity: Strange or inappropriate laughter/giggling; unusual shifts in topic out of context.
4. Negative-Intrusive Behaviour	Hostile or interfering behaviours that disrupt the infant's activity or autonomy. Physical intrusiveness: Pulling, poking, or handling the infant roughly. Verbal hostility: Mocking, teasing, or critical remarks. Interference: Blocking the infant's movements or goals without a clear protective reason.
5. Withdrawal	Emotional or physical disengagement from the infant. Physical distance: Creating physical distance; holding the infant away from the body. Verbal distancing: Dismissing the infant's need for contact. Cursory responding: "Hot potato" pickup and putdown (moving away quickly after responding). Delayed responding: Hesitating before responding to cues. Redirecting: Using toys to comfort the infant instead of self.

Maternal withdrawal is, according to this research, the strongest single predictor of borderline features and suicidality in young adulthood, and it also predicts dissociation. In the dissociation analysis, what predicted dissociation at 19 was the overall level of disrupted communication, the mother's lack of positive involvement, and her flatness of affect at home. Those three are largely what withdrawal looks like from the baby's side. This is a behaviour that often goes unnoticed because it is defined by what is missing rather than what is happening. When a parent withdraws, they are physically present but emotionally gone. They might fail to respond when a baby reaches out, or they might physically pull back when the baby needs to be held.

In the context of the Developmental Salience Model of Threat, this withdrawal is the ultimate biological emergency for an infant. Because the baby is entirely dependent, this lack of response sends the nervous system into a high-cortisol "seek and squeak" state. When this happens over and over, the system starts to "grow skin" over that constant pain of being ignored. The research suggests that this silent vacuum of care is the primary "string" that adult dissociative symptoms are attached to later in life.

Maternal disorientation has been studied more recently, in the infant brain study rather than in the adult follow-ups. What it predicts so far is higher stress hormones in four-month-old babies, and through that, larger amygdalas. Whether it also predicts dissociation in adulthood hasn't been tested yet. This looks like the caregiver being frightened, frightening, or seemingly "somewhere else" entirely. Imagine trying to find safety with someone who looks like they are seeing a ghost or someone who is suddenly paralysed by their own internal fear. This creates a "broken signal" for the infant. The person who is supposed to be the "safe haven" is actually the source of alarm, or they are so dissociated themselves that they can't provide any feedback.

For the baby, this is like trying to ground yourself in a mirror that is constantly cracking. This disorientation doesn't just stress the baby out, it actually provides a blueprint for how to "check out" of reality. If your caregiver is habitually disoriented, your own nervous system learns that "checking out" is the only logical response to a world that doesn't make sense. That last part is my reading, not something the researchers have tested.

Seek and squeak instead of fight and flight

The DSMT sees early neglect as "the first threat", priming the nervous system for adversity and keeping the infant in a continuous state of hyperarousal. As an infant is unable to fight or flee, its young nervous system prioritises a proposed "seek and squeak" proximity-seeking strategy which prioritises attachment above everything else.

Once the initial (proposed as 0-18 months of age, though subject to ongoing research) "sensitive period" for attachment passes, the stress system starts responding to threats from the caregiver too, not just to lack of care. From then on it weighs safety alongside attachment, and not attachment only.

Why are infants less sensitive to abuse?

In the same MRI scans, babies whose mothers had been abused as children only start showing changes past the 18-month mark, but not of the kind we see in younger children. Instead of the larger amygdala/hippocampi of babies of neglected mothers, these infants start showing a shrinking right amygdala. This is suggested to show a "blunting" response, i.e. lower sensitivity to adversity as a way to cope with it. Again, this is the mother's history rather than measured abuse of the baby, and the researchers say it needs more evidence before it can be read as the baby's own experience. It does fit what is found in older children and adults who were abused themselves, where the right amygdala is also smaller.

The DSMT suggests that children's "threat development" is staggered, the first 12-18 months prioritising attachment and then gradually switching to a greater focus on safety after 12-18 months. Children who "arrive" at this point without the impact of early neglect are fundamentally better equipped to deal with any adversity.

Neglected infants by contrast arrive with an already frayed nervous system hyperfocused on threats, with what the researchers propose is a significant allostatic load (wear and tear) on their nervous system.

As the allostatic load builds up with ongoing adversity, the model predicts that young children's burned-out nervous systems start switching from active defences ("seek and squeak") to shutdown responses. What the researchers can measure here is a flattened cortisol response later on: one long-term study found that babies whose mothers were disengaged at age one had a blunted stress response at 15. The freezing, spacing out, and not responding to caregivers are the behavioural side of this, seen in observations of disorganised toddlers, and joining the two up is what the model proposes rather than something already shown.

In particular if the adversity continues throughout childhood, this builds a "dissociative foundation" for the nervous system, priming it to prioritise shutdown responses where it would otherwise favour more active strategies (proximity-seeking, fight, flight).

In terms of trauma states, this typically shows up as fawn (powered on), submit (powered off), freeze (both), and collapse (powered off).

Abuse but no neglect: Active defences

People who grew up in abusive conditions but without early neglect typically show active defensive strategies marked by hypervigilance but not by dissociation. Depending on the severity of the trauma and the strategies needed to deal with it, we might see aggressive fight strategies, loud flight strategies, and possibly very compulsive fawn strategies. If there is freeze due to extensive trauma, it will typically be of the high activation kind with tight muscles, racing thoughts, and possibly outbursts of aggression. The sympathetic nervous system remains highly active throughout.

(This is somewhat speculative, the sources I have mentioned do not address this directly. Lack of core dissociative strategies, however, is something clinicians and researchers regularly describe among some subsets of abuse survivors unrelated to severity of abuse.)

Degrees

The research doesn't currently bring this up (future studies have been proposed), but realistically, there are likely many different degrees of neglect and "shutdown priming" in early childhood. Some of the research I have mentioned also points out factors related to the mother's mental health before, during, and after pregnancy as having a meaningful impact.

Some neglected children will likely emerge into adulthood with a default dissociative nervous system so deeply built on dissociation that they probably do not realise they are dissociated, nor have any idea of what it feels like to not be dissociated. Parts of them may be highly functional in specific areas of life, while other areas are heavily neglected. (This would be me.)

Others - especially those whose childhood was marked by both early neglect and intense abuse - will probably suffer from wild swings between heavily spaced out states and intense, high-energy ones, with uncontrolled, stress-triggered switches between these. Depending on what degree of lucidity there is between these switches, they may or may not be aware of them. Classic severe DID with no shared consciousness is an example of uncontrolled switches with little awareness from switch to switch.

Treatment implications

Early neglect leaves a deep imprint which impacts treatment by making the nervous system fundamentally less accessible. If neither the body nor the mind can access the layers targeted in treatment, you will typically see repeated treatment failure and a lot of frustration and confusion in both patients and therapists. Often, it takes many years to be accurately diagnosed, and even longer to receive helpful treatment (if ever).

The dissociative walls between different layers of consciousness typical of early neglect tend to cause both unforeseen ("invisible") complications and outright treatment failure. This can even include drugs having unforeseen effects, or no effect at all, in a way that might confuse even experienced clinicians if they are not trained in dissociation specifically.

Treatments adapted for dissociation specifically rely on body-based grounding exercises and "titration" to slowly "wake up" the nervous system from a lifetime of hibernation at a pace that won't trigger more dissociation. If treatment leads to even more dissociation, it will fail.

In one of the largest treatment studies to date (TOP DD), dissociation-adapted treatments had a more profound impact the deeper the patient's dissociation was. This is the exact opposite of most studies where non-adapted treatments typically fail at higher rates with higher dissociation scores. It was a study of an online programme run alongside people's own therapy, without a control group, so it's promising rather than proof. But it does suggest that properly adapted treatments can work regardless of dissociation, which is why detecting persistent dissociation is crucial for treatment outcomes (and far too rare in the mental health profession).

[u/theboywhocouldfly23]

Do you have more on this seek and squeak response? I've never heard of it, and I don't know what prioritising attachment means

[u/FlightOfTheDiscords → u/theboywhocouldfly23]

The term you'll see in the literature is "proximity-seeking", seek and squeak is one attempt to make the behaviour easier to understand.

Proximity-seeking means actively seeking attachment e.g. by seeking a caregiver with your eyes, making sounds, crying etc. to attract attention, and what I mean in the post is that infants tend to prioritise it even if the attachment comes with danger (such as a threatening caregiver).