Dynamic Systems Theory (DST)

• Shift from Neurological Maturity: Previously, motor development was seen as a result of neurological maturation. Now, it is understood through the lens of Dynamic Systems Theory (DST).

  • Dynamic: Change over time.

  • System: Interaction of multiple elements.

• Multiple Causes of motor development include:

  • Increases in strength and weight.

  • Neural mechanisms.

  • Posture control and balance.

  • Perceptual skills.

  • Motivation.

• Process: Motor skills emerge not based on when they should but how they develop, emphasizing curiosity, experimentation, and learning.

Motor Milestones

• Milestones: Not fixed, children reach them through different routes.

• Attractors: Points that most children reach, but the path is variable.

  • Fine motor skills: Grasping, object manipulation, drawing.

  • Gross motor skills: Sitting, crawling, walking, running.

  • Different muscle groups are involved—fine (small muscles) vs. gross (large muscles).

Stepping Reflex

• Early Reflex: Alternating leg movements resembling walking, seen in newborns but disappears around 2 months.

• Weight and Strength: The disappearance is attributed to rapid weight gain, outpacing the development of leg strength.

• Experimentation: Reflex can be re-triggered by putting older babies in water or younger ones with ankle weights.

Sitting Independently

• Impact on Reaching: Sitting without support aids reaching and has cascading effects on perception.

• Figure-Ground Assignment: Sitting infants develop better visual perception, including recognizing objects from the background, which helps them understand depth and plan reaching movements.

Reaching and Grasping

• Reaching: Initially swiping movements that stabilize after independent sitting.

• Anticipation: With experience, infants demonstrate anticipation in their grasping abilities.

• Soft Assembly: The combination of factors (stable base, goal location, arm control) that make successful reaching possible.

• Sticky Mittens Experiment: Sticky mittens help infants reach and grasp objects earlier than they would naturally, accelerating development.

A-Not-B Task

• Piaget's Theory: Used to test object permanence in infants (8-10 months). Infants show a tendency to search in the first location (A) even when the object is hidden in a new location (B).

• DST Perspective: Errors in the A-not-B task are due to motor memory and past attention, showing the importance of experience and interaction with the environment.

Locomotion and Walking

• Crawling: Begins around 8 months, followed by walking at about 13-14 months.

• Fear of Heights: It is debated whether crawling is necessary for infants to develop a fear of heights.

• Falling: Early walkers frequently fall, but this does not deter them; it may encourage more practice. Errors in balance and motor control provide valuable learning experiences.

Road Crossing and Risks

• Child Pedestrians: Children aged 5-14 have higher pedestrian injury rates. Children aged 6-10 are slower to enter roads and often choose smaller gaps in traffic compared to adults.

• Friends and Risks: Adolescents take more risks when crossing roads with friends compared to when they are alone.

Motor Skills and Language Development

• Motor Development and Language: Emergence of motor milestones, like sitting and walking, correlates with vocabulary development in infants.

  • Walking: Linked with greater communicative bids and vocabulary.

  • Exercise and Learning: Older children remember new vocabulary better if they engage in physical activity after learning.