Motor development Chapter 2

body scaling applied

-the use of intrinsic (relative to body size) rather than extrinsic dimensions is termed body scaling

normative descriptive period

1950s education was concerned with standardizesd tests and norms. described childrens average performacnce in terms of quantitative scores on motor performance tests. ex. they described the av. running speed and jumping and thwoing distancesof children at a specific age. Here they focused on the products more than the process. Glassow and Rarick were leaders

mcgraw

associated changes in motor behavior with development of the nervous system. considered maturation of the CNS to be the trigger for the appearance of new skills. also was interested in learning (and therefore not strinctly a maturationist)the cardiovascular, skeletal,endocrine, and even muscular systems were not deemed of primary importance to motor develop. by mid 1940s devel. psych. began to change the focus of their research.

maturationalist

believes that maturation process is controlled by internal (genetic) factors rather than external (enviro) factors. enviro. factors would affect motor develop. only temp. because hereditary factors were ultimatly in control of develop

gesell twin conclusoin

children develop in an orderly fasion (i.e developmental change came in a predictable, predetermined order over childhood

two branches of the ecological perspective:

dynamical systems perception-action approaches

maturational perspective

emphasizes biological development, specifically maturation of the CNS

System can act as a constraint that discourages the motor skil until the system reaches a specific, critical level.

ex. an infants muscular strength must reach a certain level before the legs are strong enough to support the infant's weight on one leg in order to walk. here the muscular strength would be a rate limiter, or controller for walking. until the infant reaches a critical level of leg strength (enough to support body) strength discourages walking and encourages other forms of movement, like creeping, crawling, rolling.

maturational perspective

explains developmental change as a function of maturational processes (in particular, through the central nervou system or CNS0 that control or dictate motor development. according to assumptions of this theory, motorr develop. is an internal or innate process driven by a biological or genetic time clock. the enviro. may speed or slow the process of change but it cannot change ones biologically determined course . pop in the 30s - Led by Gesell.

maturationist focus

focus on infancy, whereas descriptive developmentalists focus on late childhood and adolescence.

example of affordance

horizontal surface affords a human a place to sit, but a vertical surface does not. a squirrel can rest on a vertical tree trunk, so a vertical surface affords a squirrel a resting place. baseball bat affords an adult, but not an infant, the opportunity to swing. - hence the relationship between individual and environment is so intertwined that one's characteristics define objects' meanings, which implies that perople assess environmental properties in relation to themselves, not according to an objective standard.

affordance again:

if a person looks at an object, they directly perceive the function that the object will allow, based both on their body and on the objects size, shape, texture, and so forth. this function is affordance

more features of dynamical systems approach

it allows for the study of development across the life span. the concept of a system acting as a rate limiter, or controller, for a movement behavior applies into older adulthood as well -maturational perspective doesnt address aging because the predetermined endpoint of motor development is maturation- which occurs in the first several decades of life.

Gesell identical twins test

one twin receives a special training (experimental treatement) while other receives non (control treatment) Control develops naturally, as any child would wo special training. Looks at the effects of the enviro. on development.

key point

ppl have interpreted the maturationist perspective to mean that motor skills will automatically emerge regardless of differing enviro. this assumption has influenced many teaching, aparenting and research concepts

dynamical systems approach

ppl were researching spoken and written language . questioned the effectiveness of understanding motor control through the then-dominant information processing perspective. Intro. a new approach, called dynamical systems, as an alternative to existing motor control and coordination theories. suggested that the very organization of physical and chemical systems constrains behavior. your bodies structure removes some of the movement choices your CNS might have to make.

actual definition of scaling

process of changing the dimensions of the enviro. or an enviro. object in relation to the structural constraints of a performer

motor developmentalists were influenced by the maturational perspective but they either focus on 2 tings:

products (scores, outcomes) of development rather than on the developmental processes that led to these quantitative scores.

Gibson rejected notion of a CNS executive that performfs almost limitless calculations on stimulus info to det. the speed and direction of the person and moving object

related to perception action approach and - ecological perspective.

information processing theorists

search for age difference, whears those studying from an ecological perspective observe transitions from one skill to another (from crawling to walking)

information processing perspect3ive

sees the environment as the main force driving motor development.

Biomechanical descriptive period: (ruth glassow

she led the normative descriptive period and teh biomechanical descriptive period

ecological perspective

stress interation bw all body systems... or constraintss as well as the inseparable factors of individual, environment, and task. two related approaches to research exist: dynamical systems and perception-action approach.. Focus on how individual, environmental, and task constraints interact to encourage or discourage movement.s The concepts of rate limiters, or controllers, and body scaling eexemplify how a motor developmentalist must consider the individuals performane of a particular task in a given enviro in order to fully understand individuals motor development over the ocurse of a lifeime.

ecological perspective

stresses interrelationships between the individual, the environment, and the task. This is the perspective adopted by this text. It best describes, explains, and predict motor development

maturationists

tend to focus on the CNS as the only system relevant to development and the only rate controller. dynamical systems approach focuses on many systems and acknowledges that different systems might act as rate controllers for different skills.

how does ecological perspective differ from maturational and information processing perspectives

the dynamical systems approach suggests that coordinated behavior is softly assembled rather than hardwired, so interacting constraints in your body act together as a functional unit to let you walk. This allows for greater flexibility in walking. Lets you adapt your walk to different situations. CONCEPT OF CONSTRAINTS EXISTS FOR ecologiccal perspective

rate controller

the system that is the first to decline to some critical piont- triggers the reorganization of a movement to a less-efficient pattern. works well beecause disease or injury may strike only one system, and systems may be differentially affected by lifestyle. - active older person who works out may experience fewer declines in many of the systems than a sedentary peer.

Perception-action approach

this is the 2nd branch of the ecological perspective. proposed by Gibson during 1960s and 70s. Proposed that a close interrelationship exists between the perceptual system and the motor system and emphasized that these systems evolved together in animals and humans.

Biomechanical descriptive period

through longitudinal observations of children, developmentalists were able to identify the course of sequential improvement that children followed in attaining biomechanically efficient movement patterns. knowledge from the normative a and biomechanical descriptive perios was valuable in that it provvided educators with info on age related changes in motor development.

McGraw used twins too

to see the influence of enhanced experience on motor development. :growth of johnny and jimmy - observed them from birth. provided Johnny at around 12 months of age with challenging environments and unique tasks like climbing a ramp at a higher incline and roller skating. required motor and problem-solving skills. johnny excelled in certain motor skills but not others. did little to resovet he nature- versus nurture debate. results wer equivacol- ambiqous.

constraints concept

unique to ecological perspective (specific to the dynamical systems approach) - suggests than an indiviudal constraint or system that holds back or slows the emergene of a motor skill (rate limier or controller) can control the individuals rate of development. think: only when the slowest of the necessary systems for that skill reach a certain point may the individual perform it

affordance

used in the perception-action approach to describe the function an environmental object provides to an individual; this is related to the size and shape of the object and the indidvual in a particular setting.

do affordances change as individuals change?

yes, resulting in new movement patterns. growth in size, for ex, or enhancement in movement capabilities, might allow actions not prevoiusly afforded.- ex. is climbability of stairs an an infant- may think that since she is small and lacks strength that the infant cant climb . but as a toddler, she grows and can climb steps. Body scaling also applies to other age periods.

perception-action approach

you cannot study perception independent of movement if our finding are to be ecologically valid... i e applicable to real-world movement behavior. development of perception and teh development of movement must be studied together. also cannot study the individual while ignoring the surrounding environment. uses term affordance to describe the fxn an environmental object provides