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  • I. Theories of AgingBiological Theories of AgingPsychological Theories of AgingPsychosocial Factors and Aging

  • Theories of Aging (cont.)Aging process along with biological and psychological change and social interaction. There are many theories of aging which describe and interpret the aging process. However, Bengtson and associates (1999) pointed out two reasons of the lack of integration in theories of gerontology. 1) three different aspects of age (page 43)2) models and theories are not clearly distinguished.

  • Biological Theories of AgingGenetic TheoriesProgrammed cell deathStochastic processDNA repair mechanisms Molecular/Cellular Theories of AgingOxidationLipofuscinHeat shock proteinsSystem-Level TheoriesHomeostasisWear-and-tear theoriesStress

  • Biological Theories of Aging (cont.)Genetic TheoriesProgrammed cell death (PCD) - the process of PCD that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, loss of cell membrane asymmetry and attachment, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation.

  • Biological Theories of Aging (cont.)Apoptosis is one mechanism for the destruction of cells that have proliferated for specific purposes, such as T-cells in the immune system, and need to destroyed after accomplishing their tasks. In humans, the number of times somatic cells can replicate is partially regulated by the telomere length.Apoptosis may be a necessary process to get rid of damaged and cancerous cells (Campisise, 2001)

  • Biological Theories of Aging (cont.)2. Stochastic Processes (replication error)Hayflick (1996) stated that there may be a limited times a cell can replicate without error. This function of random (or stochastic) error is a part of aging process. DNA is susceptible to damage by a host of environmental factors, such as chemical agents (air pollution, smoking), and radiation, and internal processes such as oxidation.

  • Biological Theories of Aging (cont.)3. DNA repair mechanismsIn the process of replication, the are several different checkpoints through which the cell checks the integrity of the DNA strands. If an error is caught, replication is stopped so that repairs can made.

  • Biological Theories of Aging (cont.)Molecular/Cellular Theories of Aging1. Oxidation Free radicals or reactive oxygen species (ROS) are molecules that are generated during the oxidation process in cell. They are unstable and may interfere with the function of other molecular in the cell. The concentration of free radicals increases with age (Sohal & Weindruch, 1996) on page 49.

  • Biological Theories of Aging (cont.)2. Lipofuscin accumulated waster products in aging cells. These waster products normally are disposed via liposomal enzymes, but impaired in aging cells. Lipofuscin blocks cell proliferation and induces cell death, and may be associated with Alzeimers disease. 3. Heat shock proteins (HSPs) having cellular repair mechanism and decelerating aging process. HSPs protect cells from stress and oxidative process by regulating enzymatic processes necessary for repair and apoptosis; others refold damaged proteins into their configuration; they play a major roles in the inflammatory and immune process.

  • Biological Theories of Aging (cont.)System-level theories1. Homeostasis stability in intra- and extracellular environmental conditions, such as pH balance, blood, pressure, heart rate, temperature, and fluid balance. Homeostasis is a dynamic balance and requires communication among the various organ systems and is largely regulated by the autonomic nervous system via the neuroendocrine system. It becomes harder to maintain homeostasis as we age: 1) a decline in the production of hormones; 2) the target organs become less responsive; 3) the target organs synthesize less than optimal amount of its product.

  • Biological Theories of Aging (cont.)2. Wear-and-tear theory this theory may not hold for most organ systems. A phrase in gerontology is Use it or lose it. Many systems such as cardiovascular system, need regular and moderate exercise to maintain function, and intellectual stimulation may be necessary to the maintenance of cognitive function. However, skeleton joints may be an exception. 3. Stress is a feeling that's created when we react to particular events. It's the body's way of rising to a challenge and preparing to meet a tough situation. It could be a over-stress or moderate stress.

  • Psychological Theories of AgingThe flowchart in Fig. 3.1 (next slide) presents the intellectual history of the major theories of adult development and traces the origins of the major schools and their development from classical to modern theories.

  • Psychological Theories of AgingClassic TheoriesOntogenetic modelsSociogenic modelsCurrent TheoriesLife course theoryGoal-oriented modelsPostformal operationsConscious development

  • Psychological Theories of Aging (cont.)Classic TheoriesOntogenetic models posit that development stems from internal forces and consists of stages that are universal, sequential, and irreversible. In these models, change is discontinuous, and characterized by qualitative changes. Erikson (1950) modified Freuds psychosexual theory of early childhood to a psychosocial model that extended from birth through late life. Jung (1933) focused on adult development, believing that adolescents and young adults develop a persona.

  • Psychological Theories of Aging (cont.)2. Sociogenic models focus on life course with reference to gender, social class, culture, and cohort, and focus on change in adulthood that varies as a function of social roles and historical context or timing events. a. Disengagement theory posits a mutual withdrawal between the individuals and society as one ages.b. Active theory argues that more active the older person is, the greater life satisfaction.

  • Psychological Theories of Aging (cont.)Current Theories:Most current theories take some sort of middle ground between strict sociogenic and ontogenetic stands, but they do so with varying emphases on the context, individual goals, and the individuals choice or ability.1. Life course theory Elder (1998) has developed a life course theory which examines the ways in which cohort and historical periods affect the life course structure of individuals (Ex on page 58).

  • Psychological Theories of Aging (cont.)2. Goal-oriented models assume that older individuals have fewer resources, they must select the goals or activities the wish to pursue and optimize their performance by devoting resources to those particular goals. 3. Postformal operations more complex cognitive development in adulthood. Not only do people become more cognitively complex with age, but they also may become more emotionally complex. However, the emotional complexity may decrease in late life. Why?

  • Psychological Theories of Aging (cont.)4. Conscious development a growing sense that adult development is something that individuals do, not something that simply occurs. The development in adulthood consists of increasing mindfulness with three characteristics: 1) the continuous creation of new categories; 2) openness to new information; and 3) an implicit awareness of more than one perspective.

  • Psychological Theories of Aging (cont.)Interrelationships among theories: Early theories of adult development tended to focus on one aspect of adult development, such as personality or social, whereas contemporary theories tend to emphasize multiple influences. Most current theories emphasize some sort of conscious choice in developmental process. Some theories posit the opportunity for conscious choice as an outcome of developmental processes.

  • Psychosocial Factors and AgingFactors affecting health in late-life:1. Genetic factors may have 0 40% contributions to health.2. Other factors may have 60 100% contributions to health. However, psychological, social and physical health are tightly intertwined. 3. Psychological factors: 1) Personality A and B. 2) How and what we think affect our health.

  • II. Understanding Change in Aging ResearchBasic DefinitionsAge-Related DesignsStatistics for Assessing ChangeStatistics That Predict Change

  • Basic DefinitionsTwo basic questions in research with statistical analysis:a. Is there a difference between two or more groups on a given (dependent) variable?b. Is there an association between two or more variables?

    However, these two types of questions may be asked in different way (page 66).Different statistical methods may be used to answer these two types of research questions.

  • Basic Definitions (cont)Continuous variables:Interval (numbers) numbers that share the characteristics of ordinal and nominal measures but also have the characteristics of equal spacing between categories, such as temperature scales.Ratio (numbers) numbers that have all the characteristics of interval numbers but also have an absolute 0 point, such as incomes.Categorical variables: Nominal (numbers) numbers used to name attributes of a variable in category, such as male and female.Ordinal (numbers) numerical values that assign an order to a set of observation, such as health condition ranked from 1 = very poor to 5 = excellent.

  • Basic Definitions (cont)Bivariate two variables.Multivariate more than two variables. Partial correlation controls for one variable a, when correlating two other variables (b with c), example on page 68 (education, a, income, b, and health, c)Regression equation cause and effect relationship between dependent variable and independent variable(s).Structu


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