1. Early Motor Development
chapter 6
Early Motor Development

2. Babies Gone Wild! Interacting constraints
allow young infants to learn to drive.
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3. Early Motor Behavior Reflexive or spontaneous (Clark, 1995):
Reflexive: stereotypical responses elicited by specific external stimuli
Spontaneous: movements not caused by known external stimuli

4. Spontaneous Behaviors
Original theory: extraneous, no purpose
Current theory: building blocks, similar to some voluntary movements
Examples
Spontaneous arm movements (resemble reaching)
Spontaneous kicking (resembles adult walking)

5. Infant Kicks
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6. Reflexes Reflexive movements occur quickly after onset of stimuli.
They involve single muscle or specific group of muscles (not whole body).
They cannot be extinguished at any one time.
Persistence may indicate neurological problems.

7. Purposes of Reflexes Built-in responses facilitate survival.
Reflexes allow “dialogue” with environment.
Reflexive movements result in sensory consequences (adaptation).
Reflexes provide building blocks for future movement.

8. Asymmetrical Tonic Neck Reflex
Infant starts in supine position.
Stimulus: Turn head to one side.
Response: Same-side arm and leg extend.

9. Grasp and STNR Palmar Grasp Reflex
Stimulus: Touch palm with finger or object.
Response: Hand closes tightly around finger or object.
Symmetrical Tonic Neck Reflex
Infant starts in supported sitting position.
Stimulus: Extend head and neck or flex head and neck.
Response: Arms extend and legs flex, or arms flex and legs extend.

10. Moro Reflex Infant starts in supine position.
Stimulus: Shake head (e.g., by tapping pillow).
Response: Arms, legs, and fingers extend; then arms and legs flex.

11. Stepping Reflex Stimulus: Place soles of feet on flat surface.
Response: Legs move in walking pattern.

12. Constraints What constraints exist during the reflexive period?
Structural
Functional
Environmental physical
Environmental sociocultural
Task: goals, rules, equipment
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13. Reflexes
Go through the reflexes listed in the text. What voluntary behaviors might they be linked to? What makes you think so?

14. Later Infancy Voluntary control of movements
Understanding of environment, objects
in environment
Meaningful interactions with others
Postural reactions

15. Postural Reactions Begin around 4 months
Help maintain posture in changing environment
Initially similar to reflexes, then incorporated into general repertoire

16. Labyrinthine Righting Reflex
Infant is supported upright.
Stimulus: Tilt infant.
Response: Head moves to stay upright.

17. More Postural Reactions
Derotative Righting
Infant starts in supine position.
Stimulus: Turn head to one side, or turn legs and pelvis to other side.
Response: Body follows head in rotation, or trunk and head follow in rotation.
Parachute
Infant is held upright.
Stimulus: Lower infant toward ground rapidly.
Response: Legs and arms extend.

18. Motor Milestones Fundamental motor skills
Building blocks (leading to complex motor skills)
Cumulative, sequential
Specific movements that lead to general actions

19. Locomotor and Posture Motor Milestones
2 months: Lifts head in prone position.
3 months: Lifts shoulders (turns head).
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(continued)

20. Locomotor and Posture Motor Milestones (continued)
5 months: Rolls over, sits unsupported.
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(continued)

21. Locomotor and Posture Motor Milestones (continued)
7 months: Gets on hands and knees.
8 months: Creeps on hands and knees.
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(continued)

22. Locomotor and Posture Motor Milestones (continued)
9 months: Pulls
to stand; cruises
furniture.
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(continued)

23. Locomotor and Posture Motor Milestones (continued)
10 months: Stands alone.
12 months: Walks alone.
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24. Rate Limiters, or Controllers
Individual constraints that inhibit or slow attainment of a motor skill
Rapidly changing during early childhood

25. Rate Limiters
What important rate limiters during infancy may control development of the following?
Crawling
Reaching
Walking

26. Development of Postural Control and Balance in Infancy
Rate limiters for posture and balance appear to involve coupling of sensory information and motor response.
Infants continuously calibrate sensory motor response (Chen, Metcalfe, Jeka, & Clark, 2007).