Observe whether the child: when startled, throws arms in the air, with the palms of their hands facing up, back and neck stretched; then, quickly retracts arms back to chest (moro reflex)
Three ways this behaviour shows up as a child grows. Each level includes everyday moments to watch for.
Your baby is beginning to show a startle response, but the arm movement may be partial, brief, or not yet clearly followed by bringing the arms back toward the chest.
What you might see
Your baby, when startled, throws arms in the air, with the palms of their hands facing up, back and neck stretched; then, quickly retracts arms back to chest (moro reflex).
What you might see
Your baby shows the full startle pattern clearly across ordinary unexpected moments, then quickly settles back toward a calm posture with caregiver comfort.
What you might see
Small everyday moments where you can notice this behaviour without setting up anything special.
If your baby is naturally startled during the day, notice whether the arms go up and then come back toward the chest.
Watch whether the palms turn upward and the back or neck briefly stretches during the startle.
Do not try to frighten your baby on purpose; just notice the response if a normal startle happens.
The dataset source and any supporting developmental research.
Stenhaug, B., Ram, N., & Frank, M. C. (2021). The Stanford SHQ: A measure of early developmental milestones.
This item directly describes the Moro reflex pattern after a baby is startled.
Dubowitz, L. M. S., Dubowitz, V., & Mercuri, E. (1999). The Neurological Assessment of the Preterm and Full-term Newborn Infant.
Newborn neurological assessments include observation of primitive reflexes such as the Moro reflex as part of early motor functioning.