Primitive Reflexes: What They Are, When They Integrate, and Why They Matter
Alexis Dalrymple, COTA
Primitive reflexes are automatic, involuntary movement patterns that originate in the brainstem and develop during pregnancy. They are present at birth (and some emerge before birth) to help babies survive, develop, and interact with their environment. These reflexes are essential building blocks for neurological development and lay the foundation for movement, learning, emotional regulation, and sensory processing.
As infants grow, primitive reflexes are meant to become integrated—or inhibited—by the developing nervous system. Once integrated, they are replaced by more mature, voluntary movement patterns and postural reflexes. When a primitive reflex remains active beyond its expected age of integration, it can interfere with physical, cognitive, emotional, and academic development.
Below are some of the most common primitive reflexes, when they typically integrate, and the challenges that may occur if they remain retained.
Moro Reflex (Startle Reflex)
What it is: The Moro Reflex is an infant's automatic response to sudden changes in movement, sound, light, or position. A baby will typically throw their arms outward, inhale sharply, and then pull their arms back toward their body.
Emerges: In utero (around 9–12 weeks gestation)
Typically integrated by: 4–6 months of age
What it affects when retained:
Emotional regulation
Stress response and anxiety
Sensory sensitivities
Attention and focus
Sleep patterns
Impulse control
Difficulty adapting to change
Children or adults with a retained Moro Reflex may appear easily startled, emotionally reactive, anxious, or overwhelmed in stimulating environments. They may also experience difficulties with attention and maintaining a calm, regulated state.
Asymmetrical Tonic Neck Reflex (ATNR)
What it is: Often called the "fencing reflex," the ATNR occurs when a baby's head turns to one side, causing the arm and leg on that side to extend while the opposite arm and leg bend. This reflex helps prepare infants for rolling, hand-eye coordination, and crossing the midline.
Emerges: In utero (around 18 weeks gestation)
Typically integrated by: 6 months of age
What it affects when retained:
Handwriting skills
Crossing the body's midline
Reading and tracking across a page
Bilateral coordination
Eye-hand coordination
Left-right confusion
Fine motor skills
A retained ATNR can make activities such as reading, writing, catching a ball, or tying shoes more difficult. Children may struggle to sit comfortably at a desk or may compensate by moving their entire body instead of using isolated movements.
Symmetrical Tonic Neck Reflex (STNR)
What it is: The STNR assists babies in transitioning from lying on the floor to crawling. When the head moves, the arms and legs respond in opposite patterns, helping to develop upper and lower body coordination.
Emerges: Around 6–9 months
Typically integrated by: 9–11 months
What it affects when retained:
Sitting posture
Attention and concentration
Coordination
Crawling patterns
Muscle tone
Reading and writing posture
Physical endurance while seated
Children with a retained STNR often prefer to sit in unusual positions, such as wrapping their legs around chair legs or slumping at their desks. They may become restless or have difficulty maintaining attention during seated tasks.
Tonic Labyrinthine Reflex (TLR)
What it is: The TLR helps infants develop muscle tone, balance, and their understanding of gravity and body position. It influences how the body responds to head movements and positioning.
Emerges: At birth
Typically integrated by: Around 4 months
What it affects when retained:
Balance and coordination
Muscle tone
Posture
Spatial awareness
Motion sickness
Visual perception
Physical confidence
Retained TLR may contribute to clumsiness, poor posture, difficulty participating in sports, or challenges with balance-based activities. Children may avoid playground equipment or become easily fatigued during physical activities.
Spinal Galant Reflex
What it is: The Spinal Galant Reflex is activated when the skin along one side of the spine is lightly touched, causing the hips to move toward the stimulated side. This reflex is important during birth and early motor development.
Emerges: Around 20 weeks gestation
Typically integrated by: 3–9 months
What it affects when retained:
Attention and concentration
Fidgeting and hyperactivity
Bedwetting beyond developmental expectations
Posture
Sitting tolerance
Sensory sensitivities around clothing or waistbands
Children with a retained Spinal Galant Reflex may struggle to sit still in a classroom or become easily distracted by tags, waistbands, or the sensation of clothing against their skin.
Palmar Reflex
What it is: The Palmar Reflex causes an infant to grasp when pressure is applied to the palm of the hand. It plays an important role in developing hand function and oral-motor skills.
Emerges: Around 11 weeks gestation
Typically integrated by: 5–6 months
What it affects when retained:
Pencil grip
Handwriting
Fine motor coordination
Speech and articulation
Hand fatigue
Manual dexterity
A retained Palmar Reflex may contribute to messy handwriting, poor pencil control, or difficulties with tasks requiring precise hand movements.
Rooting Reflex
What it is: The Rooting Reflex helps infants locate food by turning their head toward touch around the mouth and cheek area.
Emerges: Around 32 weeks gestation
Typically integrated by: 4 months
What it affects when retained:
Speech development
Oral-motor skills
Feeding challenges
Drooling
Sensory processing related to the mouth
Children with a retained Rooting Reflex may exhibit oral sensitivities or difficulties with articulation and feeding.
Why Primitive Reflex Integration Matters
Primitive reflexes provide the foundation for higher-level skills such as:
Learning and academic success
Reading and writing
Emotional regulation
Balance and coordination
Focus and attention
Sensory processing
Social and behavioral development
Motor planning and organization
Posture and body awareness
When reflexes do not integrate appropriately, the nervous system may remain in an immature pattern of functioning. This can impact children both at home and in the classroom, often presenting as developmental delays, learning difficulties, behavioral challenges, or physical coordination concerns.
The encouraging news is that retained primitive reflexes can often be identified and addressed through movement-based interventions and activities that support neurological development.
With appropriate support, individuals can improve motor skills, self-regulation, learning readiness, and confidence.
Understanding primitive reflexes allows parents, educators, and therapists to look beyond behaviors and recognize the developmental foundations that may be contributing to everyday challenges. By supporting reflex integration, we help build stronger pathways for learning, movement, and lifelong success.