Motor development

1
Motor development

• Reflexes
• Reaching, grasping
• Effect of practice

2
Major milestones

• 1 month holds head straight
• 6 months sits with some support
• 8 months crawls
• 12-13 months stands alone
• 14 months walks alone
• 20 months jumps, runs

3
Reflexes

• At birth
• Babinski
• Moro
• Stepping
• Grasping
• Sucking
• Eyeblink

• few others

4
Reflexes

• At birth
• Babinski
• Moro
• Stepping
• Grasping
• Sucking
• Eyeblink

5
Reflexes

• At birth
• Babinski
• Moro
• Stepping
• Grasping
• Sucking
• Eyeblink

6
Reflexes

• At birth
• Babinski
• Moro
• Stepping
• Grasping
• Sucking
• Eyeblink

7
Reflexes

• Automatic, not voluntary
• Present at birth
• Some disappear during the first year (Moro)
• Some disappear and then reappear in a different
  form (stepping)
• Some turn into more complex forms (sucking)
• Represent subcortical mechanisms

8
Reaching

• Early reaching swipe, with usually no contact
• About 4 months reaching and grasping first
  succeeds
• By 6 months infants can predict simple
  trajectories, but can hold only one object at a
  time
• 8-9 months storage routine

9
Grasping
10
Handedness

• About 10-12 of humans are left-handed
• Inherited trait, but can be modified by training
• Hand preference starts 8 months

11
Crawling
12
Effect of practice

• Study of children in orphanage (1957) children
  were severely delayed in their movements
• Extensive practice can accelerate developments by
  a few weeks
• Cognitive and motor development reinforce each
  other movements have aims