motor development Flashcards
what are reflexes?
innate fixed patterns of action that occur in response to a particular stimulation
when do newborn reflexes fade? if they don’t, what does this indicate?
most reflexes fade during the first months – persistence can suggest motor disorders
what are the 5 newborn reflexes?
feeding reflexes, grasping reflexes, babinski reflex, stepping reflex, moro reflex
what are the 2 feeding reflexes?
ROOTING – baby turns head and opens mouth if you stroke the cheek
o Disappears at around 3 weeks and replaced by voluntary head turning
SUCKING – sucks things put in the mouth – replaced at 4 months with voluntary sucking
explain the newborn grasping reflexes (2)
- Appears in foot and hand – evolutionary remnant, clinging onto mother the way primates do today
- Disappears around 4 months when it’s replaced with voluntary grasping
explain the newborn babinski reflex (2)
- When the bottom of the foot is stroked – toes fan out and curl and foot withdraws from stimulation
- Disappears around 8-12 months
- LT persistence – indicated neurological problems
explain the newborn stepping reflex (2)
- When held upright over a flat surface – rhythmic stepping movements
- Disappears around 2 months and returns later on
explain the newborn moro reflex (2)
- Startled baby throws arms out backwards and arches back before bringing their arms back together as if holding something evolutionary sense as it would help CG catch you if they dropped you
- Disappears around 6 months
- LT persistence might indicate neurological problems
how do reflexes develop with the development of the cortex (2)
- early, simple reflexes arise from the brain stem (medulla)
- more complex, coordinated reflexes result from the development of the cerebral cortex – esp the primary motor cortex
how do voluntary movements develop with the development of the cortex (2)
- with the development of primary motor cortex (the first area to develop and responsible for voluntary movement)
- begins with raising head (1 month), control of arms (3 months) and leg control last to develop
what is the dynamic systems approach?
dynamic systems approach – a theory which emphasises influence of many factors/processes which influence motor development
not only neural mechanisms developing but increases in strength, control, motivation etc influence motor development
how does the stepping reflex support the dynamic systems view?
ESTHER THELLEN RESEARCH
o Examined infant’s performance of stepping movements
o In one experiment, weights were attached to the ankles of infants who still had the stepping reflex, and the babies suddenly stopped stepping
o In the second study, infants who no longer showed the stepping reflex were found to do so when they were suspended waist-deep in a tank of water that supported their weight. – started stepping again
o Suggests that the changing ratio of leg weight to strength was influencing the presence of the stepping reflex
o Reflex was thought to disappear at about 2 months of age because of cortical maturation, but demonstrations that the reflex could be prolonged or elicited long after it was scheduled to disappear were inconsistent with this interpretation
o Rather, the reflex is also to do with the development of the child’s strength as well which influence motor development
state the sequence of motor development
lift head, lift chest, rolls over, sit without support, stand with support, walking with support, stand alone, walk alone
how do reaching movements develop over infancy? (2)
- For the first few months children are limited to prereaching movements – clumsy swiping movements
- Infants start successfully reaching objects around 3-4 months
how does manual dexterity develop over infancy? (3)
- around 7 months as infant gain ability to sit independently, their reaching becomes quite stable
- 9-10 months – infants’ grasping approach dictated by want they intend to do with the object (Claxton et al 2003)
- by one year old, infants show sophisticated manual dexterity