The Moro Reflex in Psychology

Baby displaying the Moro reflex
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The Moro reflex, also known as the startle reflex, is an involuntary response that is present at birth and usually disappears between the ages of 3 to 6 months. The reflex occurs when an infant is startled by a loud noise or other environmental stimulus or feels that he or she is falling. The reflex causes the baby to extend the arms, legs, and fingers and arch the back.

Experts suggest that the Moro reflex evolved to help keep infants closer to protective figures and to avoid falling. Lack of a Moro reflex response in young infants may indicate auditory problems, a motor system disorder, or a disorder affecting the central nervous system.

Why Are Psychologists Interested in the Moro Reflex?

The Moro reflex is certainly interesting, but why does it interest psychologists? When striving to understand human development, psychologists often start by examining what infants can and cannot do. Very young infants cannot turn over, feed themselves, or even hold up their own heads. When examining the mental capacities of infants, psychologists focus on examining what they are capable of doing and how they respond to different stimuli in the environment.

By looking at some of the adaptive infant reflexes such as the Moro reflex, the rooting reflex, the stepping reflex, and the grasping reflex, researchers can better understand how babies respond to the world around them.

2 Sources
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  1. Children’s Hospital of Philadelphia. Newborn-reflexes.

  2. US National Library of Medicine. Moro reflex.

Additional Reading
  • Berk, L. E. (2009). Child Development (8th ed.). Boston: Pearson. ISBN 978-0-205-61559-9.

  • Kalat, J.W., & Shiota, M. N. (2007). Emotion. Belmont, CA: Thompson and Wadsworth.

By Kendra Cherry
Kendra Cherry, MS, is an author, educational consultant, and speaker focused on helping students learn about psychology.