{"id":334,"date":"2022-02-24T19:13:37","date_gmt":"2022-02-24T19:13:37","guid":{"rendered":"https:\/\/openpub.libraries.rutgers.edu\/developmentacrossthelifespan\/?post_type=chapter&p=334"},"modified":"2022-02-25T16:25:26","modified_gmt":"2022-02-25T16:25:26","slug":"chapter-1-developmental-theories","status":"publish","type":"chapter","link":"https:\/\/openpub.libraries.rutgers.edu\/developmentacrossthelifespan\/chapter\/chapter-1-developmental-theories\/","title":{"raw":"Developmental Theories","rendered":"Developmental Theories"},"content":{"raw":"

Developmental\r\nTheories<\/h1>\r\n\u201cOnly through freedom and environmental experience is it<\/em>\r\npractically possible for human development to occur\u201d.<\/em>\r\n- Maria Montessori\r\n\r\n\"\"\r\n\r\n \r\n\r\nHuman development can viewed differently depending on one\u2019s perspective. Consider the observation that when infants are curious and want to learn about their environment, they\u2019ll find a way to scoot, roll or crawl around in order to explore their surroundings. From this observation, a psychologist may suggest that cognition drives motor development. A physical therapist on the other hand, may suggest that motor development drives cognitive development because development of head control, followed by trunk control, crawling and locomotion affords infants the ability to explore the environment and learn.\r\n\r\nThe intent of this chapter is for readers to learn about different theories of development and to appreciate connections between them. Additionally it is hoped that through an understanding and acknowledgement of developmental processes, readers will able to 1) identify how a person\u2019s stage of developmental may affect functioning, and 2) establish appropriate expectations and goals given a person\u2019s state of development. This knowledge can help teachers, parents, and clinicians select strategies of engagement that will support positive development during infancy, childhood and adolescence. It addition, understanding the developmental process and aging can inform the best ways to serve and optimize functioning throughout the lifespan.\r\n\r\nHere\u2019s a review of some terms related to development and aging that will be used throughout this\r\nbook.\r\n\r\nDevelopment<\/strong> can be defined as a change in form and function. The process is: 1) continuous with changes in functional capacity, 2) related to, or associated with age, and 3) sequential.\r\n\r\nGrowth<\/strong>, from a physical perspective, means an increase is size. Growth may or may not be related to development. In children, growth is related to development of multiple organ systems. However, when a 35 year old man increases his size by gaining weight, this is not due to developmental processes. Rather, his change in size is likely due to alterations in diet and physical activity.\r\n\r\nGrowth charts which illustrate how age is associated with increases in height and weight during childhood can be found on the Centers for Disease Control and Prevention website<\/a>.\r\n\r\n\"\"\r\n

Figure 1.1 Growth Chart for Boys, Birth-36 mos.<\/p>\r\nFigure 1.1 suggests that if Billy, a 3-year old boy, is taller than 40 inches, he is in the 95th percentile for height. If he weighs 34 lbs, he is in the 75th for weight. This means that given all 3 year old boys in the US, only 5% of them are taller than Billy and 25% weigh more than he does.\r\n\r\nMaturation<\/strong> indicates progress toward maturity or a\r\nstate of functional integration between bodily systems. Most scientists consider 30 years of age to be the age of maturity. However development, especially in psychological and emotional domains,\r\ncan continue after maturity is reached.\r\n\r\nAging<\/strong> is a term typically used to explain changes in systems and functioning with the passage of time. Unfortunately, aging has a negative connotation because we associate it with decline and loss of function. Nevertheless, like growth and maturation, aging is a part of human development.\r\n\r\nSenescence<\/strong> is the most correct term for the deterioration of functioning that occurs with becoming old. Declines in function result from physiologic losses that occur after maturity. Impaired functioning increases vulnerability to stress and progressing likelihood of death.\r\n\r\n\"\"\r\n

Figure 1.2 Newell\u2019s Model of Constraints\u00a0 (1986)<\/p>\r\n\r\n

NEWELL\u2019S MODEL OF CONSTRAINTS<\/strong><\/h5>\r\n
As we begin to think about different theories and perspectives of development, Newell\u2019s Model of Constraints (1986) is a good place to start. (See Figure 1.2) Newell suggests that movements occur from the interactions of the individual, his or her environment and the desired task or goal. An underlying assumption of Newell\u2019s model is that the individual is always undergoing age-related changes and therefore, interacts with the environment and\r\ntasks in altered or modified ways over time. The key elements of the model are the constraints, which are factors that limits or discourages, but can also permit or encourage motor development.<\/h5>\r\nIndividual constraints<\/strong> are a person\u2019s unique physical and mental characteristics. Newell (1986) suggests that individual constraints can be thought of as either structural or physical. Structural constraints are related to body structure and include a person\u2019s height, weight, muscle mass, joint integrity, etc. Functional constraints refer to factors in the mental or behavioral domain such as attention, motivation, and fear. Consider the tennis player in Figure 1.3. The amputation of his legs does not prevent him from playing tennis, but it does modify the way he moves around the court and how he uses his trunk to perform his strokes.\r\n\r\n\"\"\r\n

Fig 1.3 French tennis player Nicolas Peifer<\/p>\r\n \r\n\r\nEnvironmental constraints<\/strong> are external to an individual\u2019s body and mind. In the physical environment, constraints include features such as gravity, temperature, lighting, surfaces. Through expectations, acceptance and\/or rejection, the sociocultural environment can also influence movement behaviors. Consider for example, cultures that value the arts over competitive sports, or societies in which expectations within the domain of motor development are very different for women compared to men.\r\n\r\nTask constraints<\/strong> include the goals of the movement or activity, but differ from individual goals or\r\nmotivation because these constraints are specific to the task. Take for example, the game of basketball. The goal is to get the ball into the hoop, and the rules dictate how the ball can be moved down the court. Players can dribble or pass the ball to get in shooting distance from the hoop, but they can\u2019t run down the court holding the ball. Task constraints can also include the equipment needed to accomplish the goal. In the case of basketball, imagine a 6 year old at Madison Square Garden trying to score a basket using a regulation size ball. Now imagine that same 6 year old trying to get the ball through the hoop using a size 3 mini-basketball with the hoop set at 6 feet, rather than 10 feet. Without doubt, the movement patterns she uses (and probably her success rate) will be different in the two described situations, based on the equipment used\r\nto perform the task.\r\n\r\nIt\u2019s important to keep in mind that development is indeed expected to proceed in a fairly stereotypical manner and that certain universal behaviors such as self-feeding, talking, walking, etc. are expected to emerge within a predicted stage of development. Nevertheless, individual differences in development do exist, such as the infant who never crawled, but who has achieved walking by 8 months of age. Parents, teachers and rehabilitation professionals often need to consider individual differences that have been influenced by a variety of constraints as well as the context of universal behaviors when assessing whether an individual\u2019s behavior or performance in within or outside the range of typical development.\r\n

BIOPHYSICAL THEORIES OF DEVELOPMENT:<\/strong>\r\nMOTOR<\/strong><\/h5>\r\nNeuro-maturational<\/strong> Theory<\/strong>\r\n\r\nTheories of motor development have emerged and evolved over time, in part due to advancements in scientific technology. The neuro-maturational theory purports that structure precedes function and that development and changes in motor skills are the result of the development and maturation of the central nervous system (CNS). In other words, the nervous system prescribes changes in movement. Dr. Arnold Gesell, an American psychologist and pediatrician observed and filmed approximately 12,000 children at various ages and stages of development. He concluded that children must reach specific maturational stages in development before learning can influence behavior and that a hereditary scheme for development exists for motor skills, adaptive behavior, language development, and social sills. In his book, \u201cInfancy and Human Growth\u201d (1928), Gesell suggested a developmental schedule based on his theory, which was widely used by many practitioners. Today, critics have challenged Gesell\u2019s theory because he gave little thought to environmental factors that could influence development and observed largely middle-class children in a university setting. Nevertheless, Gesell\u2019s research findings continue to guide many on what infants should be able to do and when.\r\n\r\nGesell provided 5 basic principles of development\r\nbased on his observations of developing infants.\r\n