Imagine for a moment: an infant, lying in their crib. A sharp noise echoes. Instantly, they spread their arms, open their hands, and then close them. This movement, you did not teach them. It is an archaic reaction. A neurological remnant of our evolution.
These automatic movements, known as archaic reflexes, are programmed from intrauterine life. They are essential for survival, attachment, and the motor and sensory development of the baby. However, when they do not integrate properly, they can interfere with development (sometimes in an invisible way) until adulthood.
This comprehensive guide offers you the keys to understanding their role, persistence, impacts, and integration. Whether you are a parent, educator, therapist, or simply curious, this exploration could change your perspective on behavior and posture, in both children and adults.
An archaic reflex (or primitive reflex) is an automatic, stereotyped motor response that appears in the fetus or infant. It is triggered by specific sensory stimulation (touch, sound, head movement...).
These reflexes are produced by the brainstem, an ancient region of the brain, and precede any voluntary control. Their role is fundamental:
Facilitating birth (e.g., Galant Reflex)
Assisting feeding (e.g., Rooting Reflex)
Building the neurological foundations of movement (e.g., ATNR, STNR)
Helping to regulate primary emotions (e.g., Moro Reflex)
These reflexes must gradually be inhibited or “integrated” between 3 months and 1 year. This means they give way to more mature and voluntary motor responses, under cortical control.
In some children (and adults), one or more archaic reflexes remain active beyond the expected age. This non-integration can have several causes:
Disrupted birth (cesarean, premature birth, very rapid or very prolonged delivery)
Lack of free motor exploration (baby too contained, immobilized, over-carried)
Early stress or unstable environment
Neurodevelopmental disorders (ASD, ADHD, DYS, childhood anxiety)
Absence of cross-body stimulation (little time on the ground, no free play)
It is also possible that some reflexes have been partially integrated, complicating their identification and long-term effects.
One or more active reflexes can interfere with:
School learning: writing, reading, concentration
Posture and coordination: difficulties sitting still, clumsiness
Sensory capacities: hypersensitivity to noise, touch, light
Emotional regulation: frequent outbursts, fear, anxiety, social withdrawal
Example:
A child with an active ATNR (Asymmetrical Tonic Neck Reflex) will struggle to coordinate their eyes and hands. Writing becomes a challenge. Their body tenses as soon as they turn their head. They tire quickly in class.
Non-integrated reflexes in adulthood can manifest as:
Persistent cognitive fatigue
Chronic anxiety, emotional hypersensitivity
Postural tensions, back or neck pain
Difficulty organizing tasks, procrastination, mental overload
For example, an adult with an active Moro reflex may live in a constant state of alertness. They jump at the slightest noise, sleep poorly, and constantly struggle to “settle down.”
Startle reaction in response to a strong sensory stimulus. Prepares the nervous system for stress management. An unintegrated Moro can lead to panic reactions, sleep disorders, and emotional hypersensitivity.
👉 Read the full article on the Moro reflex
Lateral flexion of the trunk when one side of the spine is stimulated. Helps with birth and the initiation of walking. Its persistence is linked to motor difficulties in the back and restlessness.
👉 Read the full article on the Galant reflex
Activates the extension of one arm and the flexion of the other according to head rotation. Essential for lateralization. Its persistence disrupts writing, reading, and coordination.
👉 Read the full article on the ATNR
Related to forward/backward head movements and their impact on arms/legs. Prepares for the transition from sitting to crawling. If it remains active: difficulty with posture, balance, and muscle tone.
👉 Read the full article on the STNR
Automatic closing of the fingers around an object. Important for attachment and fine motor skills. Can interfere with manual autonomy and writing fluidity.
👉 Read the full article on the grasping reflex
Extension of the toes when the sole is stimulated. Allows assessment of neurological maturation. Persistence: tensions in the feet, walking disorders.
👉 Read the full article on the Babinski reflex
Stepping movements when the baby is supported in a standing position. Anticipates the walking pattern. Persistence: rigid gait, uneven support, fatigue when standing.
👉 Read the full article on the automatic walking reflex
Automatic head turning towards a facial stimulus. Serves for breastfeeding and oro-facial development. Its persistence can lead to sucking, chewing, and language disorders.
👉 Read the full article on the rooting reflex
Often gets up in class, fidgets, falls easily
Laborious, illegible, tense writing
Fear of heights, movement, separation anxiety
Difficulty crossing the midline (e.g., passing an object from one hand to the other)
Tensions in the trapezius or lower back
Need for constant control, chronic stress
Stiff or slouched posture, unstable coordination
Attention disorders or weak working memory
A trained professional (psychomotor therapist, physiotherapist, sports coach, specialized occupational therapist) can conduct an archaic reflex assessment.
Fun sessions, rhythmic movements, floor play, and cross-stimulation are often enough to integrate reflexes in little ones.
Programs like RMTi or INPP, accompanied by specific daily exercises, allow for lasting integration.
Even at 30, 40, or 60 years old, the brain can reorganize its connections. The process takes longer, but it is liberating.
The key? Slow, conscious, and cross repetition of the reflex movement until its automatic deactivation.
In a world where children sit too early, move too little, are overstimulated but under-coordinated, primitive reflexes are less often naturally integrated. We see the emergence of:
Increasing attention disorders
Children becoming more sensitive and anxious
Disorganized postures from preschool
Chronically tense adults with no medical explanation
These are not just “school problems” or “stress issues.” They are sometimes immature neurological responses that are still awaiting integration.
Archaic reflexes are the invisible foundations of human development. When well integrated, they free movement, attention, emotion, and confidence. When they persist, they hold us back.
But it is never too late. The body retains memory of its reflex pathways. It just takes revisiting them, patiently, to unlock untapped potential.
Discover the Moro reflex, this archaic reflex that protects your baby in case of a fall. Learn how it influences their development and the impacts of an unintegrated Moro.
Discover the Asymmetrical Tonic Neck Reflex: essential for coordination and motor development. Understanding its impact on writing and posture is crucial!
Discover the Symmetrical Tonic Neck Reflex, a key reflex for motor development. Learn how its integration influences posture and coordination!
