Early Motor Development chapter 5 Early Motor Development

Early Motor Behavior Can be reflexive or spontaneous (Clark, 1995) Reflexive: stereotypical response elicited by a specific external stimuli Spontaneous: movements not caused by known external stimuli

Spontaneous Behaviors Assumed to be extraneous movements with no purpose Similar to “mature” movements Examples Spontaneous arm movements and reaching Spontaneous kicking and adult walking

Infant Kicks Click image to view video

Reflexes Reflexes occur quickly after onset of stimuli. They involve a single or specific group of muscles (not the whole body). They resist habituation (at any one time). Persistence may indicate neurological problems.

Purpose of Reflexes Built-in responses facilitate survival. They enable open dialogue with the environment. Reflexive movements result in sensory consequences (adaptation). Reflexes provide building blocks for future movement.

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

Symmetrical Tonic Neck Reflex Infant starts in supported sitting. Stimulus: extend head and neck or flex head and neck. Response: arms extend and legs flex, or arms flex and legs extend.

Palmar Grasp Reflex Stimulus: touch palm with finger or object. Response: hand closes tightly around object.

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.

Stepping Reflex Stimulus: place soles of feet on flat surface. Response: walking pattern of legs.

More Reflexes Sucking reflex Stimulus: touch face above or below the lips. Response: sucking motion begins. Babinski reflex Stimulus: stroke sole of foot from heel to toe. Response: toes extend.

Constraints What constraints exist during the reflexive period? Structural Functional Environmental physical Environmental sociocultural Task: goals, rules, equipment Click to add notes

Later Infancy Gain voluntary control of movements Understanding of environment, objects in the environment Meaningful interactions with others Postural reactions

Postural Reactions Begin at around 4 months Help to maintain posture in a changing environment Initially, similar to reflexes; later, incorporated into general repertoire

Labyrinthine Righting Reflex Infant is supported upright. Stimulus: tilt infant. Response: head moves to stay upright.

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 held upright. Stimulus: lower infant toward ground rapidly. Response: legs and arms extend.

Motor Milestones Fundamental motor skills Building blocks Cumulative, sequential Lead to future complex motor skills Specific movements that lead to general actions

Locomotor and Posture Motor Milestones: An Example Emily at 2 months (continued)

Locomotor and Posture Motor Milestones (continued) 2 months: lifts head in prone 3 months: lifts shoulders (turns head) (continued)

Locomotor and Posture Motor Milestones (continued) 5 months: rolls over; sits unsupported (continued)

Locomotor and Posture Motor Milestones (continued) 7 months: gets on hands and knees 8 months: creeps on hands and knees (continued)

Locomotor and Posture Motor Milestones (continued) 9 months: pulls to stand; cruises furniture Click to add notes (continued)

Locomotor and Posture Motor Milestones (continued) 10 months: stands alone 12 months: walks alone

Rate Limiters, or Controllers Individual constraints that inhibit or slow the attainment of a motor skill Rapidly changing during early childhood periods