Motor Development: Why Babies Step Before They Walk
How movement emerges and changes across the lifespan, from newborn reflexes and growth spurts to the aging athlete.
Try 3 questions
1. Newborns make stepping movements when held upright, but these vanish by about two months. What did researcher Esther Thelen show?
- Legs gain mass faster than strength
- The brain deletes the reflex circuit
- Babies simply forget how to step
Show the answer
Answer: Legs gain mass faster than strength
Thelen found the disappearance matched rapid gains in leg fat and weight; the movement pattern remained but the muscles could not lift the heavier legs.
2. What happened when infants who had stopped 'stepping' were held with their legs submerged in water?
- The stepping movements returned
- They stopped moving their legs
- They began swimming strokes
Show the answer
Answer: The stepping movements returned
Water's buoyancy reduced the effective weight of the legs, and the stepping pattern reappeared, supporting a biomechanical rather than purely neural explanation.
3. A newborn's palmar grasp reflex can be strong enough to do what?
- Lift an adult's arm off a table
- Briefly support the baby's own weight
- Hold a spoon steady for feeding
Show the answer
Answer: Briefly support the baby's own weight
Many newborns can briefly hang from an adult's fingers using the grasp reflex, which fades over the first months as voluntary grasping develops.
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