Unformatted text preview: Chapter 2: Theoretical Perspectives Research Methodology To interpret developmental "facts", must first understand the different theoretical perspectives from which these "facts" emerge... Normative research Standardized tests and norms ~ quantitative scores Focus on product versus developmental processes Descriptive research Biomechanical descriptions of movement patterns Longitudinal observations ~ qualitative descriptions Longitudinal An individual or a group is observed over time Attempts to explain behavior changes over time; involves recording various aspects of individual motor behavior over time (several years) Measure age-related changes in behavior intra-individual change Cross-Sectional Individuals or groups of different ages are observed Change is inferred, not actually observed Data is collected on different groups of people at varying age levels at same point in time random selection representative sample Not actually developmental studies description of behaviors at specific ages Used for group comparisons Major Theories of Motor Dev't Maturational perspective Information processing perspective Ecological perspective Dynamic Systems Perception-Action 3 basic themes within these developmental theories: -active vs passive (internal vs external forces) -nature vs nurture -constant vs stage-like Maturational Perspective Maturational perspective explains developmental change as a function of maturational processes (primarily CNS) that control or dictate motor development Innate process driven by a biological or genetic time clock Developmental change as function of maturation of different systems Primarily the central nervous system Environment has little influence Although may impact rate of development Environment cannot change one's biologically determined course Markers of motor development are qualitative and discontinuous events i.e., stages of development History of Maturational Perspective Popular during the 1930s An invariable, genetically determined developmental sequence exists; the timing or rate of dev't is likely individually determined Genetics primarily responsible for motor dev't Environment may have temporary effects 100% nature motor dev't = passive process Used co-twin control strategy One twin receives specific training (experimental treatment); other twin receives no training (control) Allowed developmentalists to identify sequences of skill development and variability in rate of skill onset Processes underlying development Associated changes in motor behavior with development of the nervous system Maturation of CNS triggered appearance of new skills Myrtle McGraw changes in motor behavior associated with development of nervous system Learning of motor skills Development was primary focus ~ learning was overlooked Nervous system only important system in development -- CV, skeletal, endocrine, or even muscular systems were not deemed to be of primary importance to motor development -- Even today many researchers, teachers, and practitioners feel its unnecessary to facilitate development of basic skills Maturational Perspective - Summary Resulted in long-lasting beliefs / stereotypes Basic motor skills will emerge automatically There is no need for special training Mild deprivation does not arrest development Nervous system is most important system Maturational perspective is still used in research to identify naturally occurring sequences of development By mid-1940s, physical educators took up the study of motor development (maturational perspective), and methodology shifted towards describing movement and identifying age group norms Researchers continued to identify naturally occurring sequence of changes Methodology Maturational Perspective Normative description Describes children's average performance by quantitative scores ~ compared to norms 1950s education became concerned with standardized tests and norms As a result, children's performances were described in terms of quantitative scores on motor performance tests Research primarily focused on products (scores, outcomes) of development rather than the developmental processes that led to these quantitative scores Biomechanical descriptions Fundamental movement skills and patterns Glassow made careful biomechanical descriptions of movement patterns children used in performing fundamental movement skills Halverson took these descriptions a step further with longitudinal observations As a result, researchers were able to identify the developmental course through which children moved in the attainment of biomechanically efficient movement patterns Taken together, the normative and biomechanical descriptive periods provided educators with info. ~ age-related changes in motor dev't Information Processing Basic tenet: the brain is like a complex computer. Human (passively) responds to external stimuli Stimulusresponse links feedback knowledge of results Responses are strengthened through experience 100% nurture Well learned skills are performed at relatively automatic level Information Processing Info. processing takes time because the brain inputs the info, processes it, and then ouputs the movement Process of motor learning and development occurs as a response to some external or environmental input This theoretical perspective appeared around 1970 Emphasizes concepts such as formation of stimulus-response links, feedback, and knowledge of results Researchers studies many aspects of performance attention, memory, effects of feedback across age levels Perceptual-Motor Development Framework of information processing 1960s - attempted to link learning disabilities (~ cognitive processes) to delayed perceptualmotor development 1970s research had changed focus to dev't of sensory and perceptual abilities Within the framework of info. processing, some developmentalists continued to study perceptual-motor development 1960s studied link b/n perceptual and motor, by 1970s researched moved towards study of sensory and perceptual abilities Chapters 9 and 10 we will focus more specifically on sensory and perceptual development Ecological Perspective Basic tenet: interrelationship between individual, environment, and task drives development Importance of multiple systems 1980s ecological perspective became increasingly dominant At any given moment, how you move is related to your body and the environment, but also must
take into account the complex relationships among many internal and external factors Decisions of higher brain centers reduced Perception of environment is direct Muscles self-assemble into functional groups Two branches exist: Dynamic systems (motor control and coordination) Perceptionaction (perception) Info processing proposes that a single "executive" function decides all action, based on processing of perceptual info and then outputs hundreds of control commands to the individual muscles Muscles cannot simply self-organize...organized into functional groups is more plausible Ecological perspective considers motor development to be the development of multiple systems (vs just CNS maturational perspective) Because these different systems change throughout life, motor development is considered a lifelong process Dynamic Systems Behaviour is constrained by the organization of physical and chemical systems Structural organization of human body encourages (or constrains) walking Body systems spontaneously self-organize Ability to adapt walking pattern to diff. environments Behaviour emerges from inter-relationships between body's systems, individual's environment, and task demands Dynamic systems ~ coordination Takes into account different systems that exist both within the body (CV, muscular) and outside the body (ecosystem, social, cultural) Some systems may develop more slowly than others in the young or degrade more rapidly in the old and thus control the rate of development or change Development is characterized by qualitative and discontinuous change Change occurs across the life span Rate limiters, Active, Nature and Nurture, Discontinuous PerceptionAction Interrelationship between the perceptual system and the motor system An affordance is the function an environmental object provides to an individual Characteristics define objects' meanings People assess environmental properties in relation to themselves, not according to an objective standard Example people assess a flight of stairs by the height of each stair in relation to the climber's body size Known as body scaling Object functions are based on individuals' intrinsic dimensions (body scaled) rather than extrinsic, objective dimensions. Example: a horizontal surface affords a human a place to sit, where as a vertical surface does not Affordances change as individuals change, resulting in new movement patterns Ecological Perspective - Summary Both dynamic systems and perception-action perspectives reject the notion that CNS acts as the executive ~ controlling nearly unlimited opportunities for movement Control is distributed throughout the body, at both global and local levels Ecological perspective allows new ways of thinking about and approaching old questions Discussion Questions 1. Who are the key researchers in the field of motor development from the 1920s until today? - Arnold Gessel: o 1930s o Led maturational perspective research o Co-Twin experiment - Myrtle McGraw: o 1940s o Maturation of the CNS associated with motor development - Ruth Glassow: o 1950s o Normative and Biomechanical Descriptions - Kugler, Kelso, Turvey: o 1980s o Ecological perspective dynamic systems - JJ Gibson: o 1960s-70s o Perception-action approach 2. How can a teacher or therapist use the concept of body scaling to help individuals develop different motor skills? -use different sized sports equipment for children -example: smaller and lighter baseball bats to teach children how to swing ... 3. Why should physical educators be interested in affordances? -... ...
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- Fall '07
- Motor control, DYNAMIC SYSTEMS, maturational perspective