1/4H LabO 230 - The Moro Reflex Decoded

Do you startle easily at the slightest unexpected noise? Do you sometimes feel in a constant state of alertness, with no apparent reason? This heightened sensitivity may find its roots in a fundamental neurological program established long before your birth: the Moro reflex. Often perceived as merely a baby’s startle, this reflex is, in reality, much more complex. It is an archaic survival program that intimately connects our vestibular system (the sense of balance), our management of stress, and our need for emotional security. Far from being a mere pediatric curiosity, it continues to influence our posture, emotions, and reactivity well into adulthood.

Get ready to discover 5 counterintuitive revelations that will profoundly change your perception of this fascinating mechanism and its impact on our daily lives.

1. The real trigger is not the noise, but the fall: the secret of the vestibular system

Understanding the true trigger of the Moro reflex is essential to grasp its profound nature. Contrary to a widespread belief, its primary cause is neither a loud noise nor a sudden light, but a vestibular imbalance. It is the sensation of falling, of losing one’s bearings in space, that activates this survival program. Although the vestibular system is located in the inner ear, it is its function as an organ of balance, rather than hearing, that is at play.

This assertion is strongly supported by scientific research. A study by Ronqvist (1995) demonstrated that a rapid drop of the body in space triggers an immediate Moro response, even without any head movement. Even more surprisingly, researchers observed a vestibular lateralization: in some babies, the right arm reacts faster than the left, revealing a difference in activity between the two labyrinths of the inner ear. Even more conclusively, the study by Bloomfield (2008) on children with Charge syndrome revealed that those born without functional semicircular canals exhibited no Moro reflex.

The conclusion is clear: without a vestibular system, the Moro reflex does not exist. It is primarily a response to a loss of stability, which explains why its dimension is not only physical but also deeply emotional.

2. More than a startle, an emotional cry for help from birth

It is surprising to note that a physical reflex can carry such rich emotional significance from the very first moments of life. The complete Moro sequence – a phase of arm extension, a cry or a strong inhale, followed by a phase of flexion – is not a mere mechanical movement. It is a complete neurological program, with its command center located in the lower part of the brainstem, making it a deeply automatic and subcortical reaction.

According to the work of Rousseau (2017), this reflex embodies a fear of separation and an instinctive need for attachment. The baby, sensing the loss of support, does not merely react physically; it communicates distress and seeks to cling on, to regain contact and safety. From the outset, the Moro reflex is thus both motor, vestibular, and affective.

It is not a mere muscle contraction; it is an embodied emotion.

This archaic emotional response, wired into our nervous system, lays the groundwork for how our body and brain will learn to manage stress and insecurity throughout our lives.

3. The baby reflex that explains adult hypersensitivity and stress

How can a neurological program from early childhood have such lasting repercussions? If the Moro reflex does not integrate properly and remains active, it can leave a mark on our nervous system. The brain then continues to react disproportionately to minor stimuli: an unexpected event, a slight loss of balance, a sensory surprise. This phenomenon is particularly evident in hypersensitive children, overwhelmed by stimulating environments, or in certain athletes who overreact under pressure, their bodies interpreting physical imbalance as a signal of imminent danger.

This mechanism is based on what is called the “archaic alert loop”. Vestibular stimulation not only activates a motor response via the brainstem and reticular formation but also triggers an emotional fear response through the amygdala and hypothalamus. It is also crucial to note that if this reaction is triggered by very intense external stimuli, it may be linked to another mechanism, the paralysis fear reflex, which requires a different therapeutic approach.

This raises a crucial question: if this reflex is so important, how can it be reliably assessed?

4. The classic test is a trap: why to be cautious

Paradoxically, the most well-known test for assessing the Moro reflex is also one of the most biased. The classic test, which involves slightly dropping the head backward, is far from an objective measure as its outcome greatly depends on the subject’s trust in the tester, their expectations, and their emotional state at the time.

A study conducted by our team in a school setting in 2025 perfectly illustrates this: in a new environment, 100% of children tested positive. This result does not mean their reflex was unintegrated, but rather that their bodies were in a state of normal alertness appropriate to the situation. For this reason, our clinical approach is radically different and prioritizes safety. The goal is not to determine whether the reflex is “present or absent,” but to understand how the person manages the loss of stability.

Our recommendation is as follows: we test only once. In fact, we are not even obliged to test it at all. If a person already shows clear vestibular or emotional difficulties, we do not confront them with this loss of control. We keep them safe and observe other more relevant markers: gaze stability, balance quality, respiratory regulation, and behavior in the face of imbalance.

5. We do not “erase” it, we restore bodily security

The goal of working on a persistent Moro reflex is never to eradicate it. It is an essential survival program. What we seek is to rebuild the neurological foundations of security so that the brain no longer needs to trigger this alarm excessively. The strategy is to restore overall balance by following several logical steps.

1. Soothing the alert system: First and foremost, the nervous system must be calmed. We start with slow, controlled, and progressive movements, coupled with breathing exercises to promote a return to calm (parasympathetic system).

2. Reintegrating the vestibulo-postural axis: Once the system is calmed, we restore stability in gravity. We use specific exercises like the labyrinthine tonic reflex, the Landau reflex, or positions that engage the head in all planes to work on the coordination between the eyes, head, and body.

3. Recovering “reactive” stability: The next step is to develop the ability to quickly return to balance after a disturbance (a jump for an athlete, a surprise for a child). The goal is for the person to manage the loss of stability without triggering the fear response.

4. Adapting to the period (for athletes): It is crucial to avoid this type of work in the month leading up to a major competition. Integration exercises can temporarily modify muscle tone and sensory perception, so this is foundational work to be done well away from deadlines.

By restoring this bodily security, we provide the brain with the tools to stop overreacting, which paves the way for better emotional regulation.

Conclusion

The Moro reflex is much more than just a startle. It is a “mirror of stress” that reveals the inseparable union between our body, our sense of balance, and our emotions. It teaches us that as long as the body does not feel stable, the brain cannot feel safe. This understanding radically changes our approach to well-being, reminding us of a fundamental truth: without physical stability, we cannot build emotional stability.

Remember, before calming the mind, we must first stabilize the body.