CHAPTER 1 UNDERSTANDING LIFESPAN HUMAN DEVELOPMENT Learning Objectives • How do developmental scientists define • development? What does the typical path of development look like across the.
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CHAPTER 1 UNDERSTANDING LIFESPAN HUMAN DEVELOPMENT Learning Objectives • How do developmental scientists define • development? What does the typical path of development look like across the lifespan? What Is Development? • Systematic changes and continuities in an individual – Occur between conception and death • From “womb to tomb” • Changes and continuities occur in three broad domains – Physical – Cognitive – Psychosocial What Is Development? • Development involves gains, losses, neutral changes, and continuities in each phase of the lifespan – Includes growth • Physical changes that occur from conception to maturity – Includes stability – Includes aging • Range of positive and negative physical, cognitive, and psychosocial changes – Biological aging » Deterioration that leads inevitably to death Conceptualizing the Lifespan • • Age grade: socially defined age group in a society – Confers statuses, roles, privileges, responsibilities – Rites of passage mark transitions Age norms: behavioral expectations by age – Basis for the social clock, which influences • Our sense of when things should be done • Our adjustment to life transitions – Age norms in our society have weakened Conceptualizing the Lifespan • Conceptualizations of the lifespan vary from culture to culture and from subculture to subculture – Ethnicity • Classification or affiliation with a group based on common heritage or traditions – Ethnic groups have different age norms and different developmental experiences – Socioeconomic status (SES) • Standing in society based on such indicators as occupational prestige, education, and income – Can influence age at which milestones of adulthood are reached Learning Objective • How has our understanding of different periods of the lifespan changed historically? Phases of the Lifespan in History • • • • • Childhood: view emerged in the 17th century of children as innocents to be protected and nurtured Adolescence: emerged as a distinct phase of the lifespan in the late 19th, early 20th centuries Emerging adulthood: the most recently defined phase, from age 18 to age 29 Middle age: recognized in the mid-20th century Old age: defined in the 20th century Development in the Future • Life expectancy – The average number of years a newborn can be expected to live • In the early 21st century, a newborn’s life expectancy is 78 years – 81 for a white female – 77 for a black female – 76 for a white male – 70 for a black male • Differences between women and men and between races have narrowed. • Differences between high and low SES groups have widened Learning Objectives • What are the main elements of the nature• nurture issue? How does the bioecological model of development address the nature-nurture issue? The Nature-Nurture Issue in Development • Nature: the influences of heredity – Emphasis upon the process of maturation • Biological development according to a genetic plan • Nurture: the influences of environment – Emphasis upon learning • Experiences cause changes in thoughts, feelings, and behaviors The Ecology of Development • Urie Bronfenbrenner proposed a bioecological model to explain how biology and environment interact in development – Microsystem: immediate environment – Mesosystem: linkages between microsystems – Exosystem: linkages of social systems – Macrosystem: larger cultural context – Chronosystem: changes occur in a time frame • Caption: Urie Bronfenbrenner’s bioecological model of development pictures environment as a series of nested structures. The microsystem refers to relations between the developing person and her immediate environment, the mesosystem to connections among microsystems, the exosystem to settings that affect but do not contain the individual, the macrosystem to the broader cultural context of development, and the chronosystem to the patterning over time of historical and life events. Researchers face many challenges in studying the developing person in context. Learning Objectives • What goals guide the work of developmental • • researchers? What are some of the key events in the history of the study of lifespan development? What are the key assumptions of the modernday lifespan perspective? Goals of Studying Lifespan Development • Description – Normal development and individual differences • Explanation – Typical human development and individually different development • Optimization – Positive development and enhanced capacity – Preventing and overcoming difficulties Applying Research on Development • Evidence-based practice – Used by teachers, mental health professionals, nurses, other helping professionals • The practice of using research-based methods and proven curricula or treatments The History of Studying Lifespan Development • The first scientific investigations – Baby biographies • The most influential: Charles Darwin • G. Stanley Hall – The founder of developmental psychology – Developed the questionnaire – Suggested adolescence is a time of storm and stress Modern-Day Lifespan Perspective • Development is a lifelong process • Development is multidirectional • Development involves both gain and loss • Development is characterized by lifelong • • • plasticity Development is shaped by historical-cultural context Development is multiply influenced Development must be studied by multiple disciplines Learning Objectives • What characterizes the scientific method • • used by those who study lifespan development? How do researchers use theory? What characterizes a good theory? The Scientific Method • The scientific method is an attitude • – Believe the data, the findings of research The scientific method involves a process of generating ideas and testing them by making observations – Preliminary observations provide ideas for a theory – Theories generate hypotheses The Scientific Method • Theory – A set of concepts and propositions intended to describe and explain phenomena • Example: Jean Piaget’s theory to describe children’s cognitive development – Theories generate hypotheses • Predictions that can be tested regarding a particular set of observations Theory in the Scientific Method • Theories generate hypotheses • Hypotheses are tested through observations • New observations indicate which theories are • supported or should be revised or discarded A good theory should be – Internally consistent – Falsifiable – Supported by data • Caption: The scientific method in action Learning Objectives • How do developmentalists collect data? • What methods do developmental scientists use to examine the relationships among the variables that affect development? Sample Selection • A research study focuses on a research • sample for the purpose of generalizing to a larger population from which the sample is drawn and about which conclusions can be made Best approach is to study a random sample – Identify the population and use random means to select a portion to be studied Data Collection Methods - Verbal Reports • Verbal reports – Use interviews, written questionnaires or surveys, etc. to ask people about themselves – Shortcomings of verbal reports • Cannot be used with infants, those who cannot read or understand speech, etc. • Results may reflect age differences in understanding • Responses may be socially desirable Data Collection Methods – Behavioral Observations • Naturalistic observations – Observing people in their natural surroundings and in everyday life • Used to study infants and children who lack verbal skills – Limitations of naturalistic observations • Cannot be used for rare or infrequent behaviors • Difficult to determine cause and effect • Presence of observer can influence the behavior that is being observed Data Collection Methods – Behavioral Observations • Observations can be structured – Achieve more control over the conditions of observation by creating tasks or conditions related to the behavior of interest – Limitations of structured observations • Research participants may not behave naturally in the structured situation • Conclusions drawn from structured situations may not generalize to natural settings Data Collection Methods - Physiological Measurements • Example: Functional magnetic resonance • • imaging (fMRI) measures an increase in blood flow to an area of the brain that occurs when the area is active Advantages of physiological measurements – Hard to fake – Useful in study of nonverbal infants Limitations of physiological measurements – Not always clear what is being assessed Learning Objectives • What are the essential features of the case • • study method of testing hypotheses? What sorts of information can be gathered from this type of study? What are its advantages and limitations? • Methods for Testing Hypotheses – Case Study Case study – An in-depth examination of an individual or small number of individuals – Advantages of the case study method • Can provide rich information about complex or rare aspects of development • Can be a good source of hypotheses for future larger-scale studies – Limitations of the case study method • Conclusions cannot be generalized Learning Objectives • What are the essential features of the • • experimental method for testing hypotheses? What sorts of information can be gathered from this type of study? What are its advantages and limitations? Methods for Testing Hypotheses – The Experimental Method • Experiment – The investigator manipulates or alters some aspect of the environment to determine how this affects the behavior of the sample of individuals who are being studied – The goal is to see whether the different treatments (independent variable) have differing effects on the behavior expected to be affected (dependent variable) Methods for Testing Hypotheses – The Experimental Method • Three critical features of true experiments – Random assignment of individuals to treatment conditions – Manipulation of independent variable – Experimental control • All factors other than the independent variable are controlled or held constant so they can’t contribute to the differences among the treatment groups • • Methods for Testing Hypotheses – The Experimental Method Advantages of the experimental method – Can establish cause and effect • Manipulation of the independent variable causes a change in the dependent variable Limitations of the experimental method – Findings of laboratory experiments don’t always hold true in the real world – Principles of ethics limit the use of experiments to study human development • Methods for Testing Hypotheses – The Experimental Method Quasi-experiment – An experiment-like study that evaluates the effects of different treatments but does not randomly assign individuals to treatment groups Learning Objectives • What are the important features of the • • correlational method of testing hypotheses? What sorts of information can be gathered from this type of study? What are its limitations and advantages? Methods for Testing Hypotheses -The Correlational Method • Correlational method – Determines if two or more variables are related in a systematic fashion • The strength of the relationship is expressed by the calculation of a correlation coefficient – An index of the extent to which one variable is systematically related to another variable – Can range from +1.0 to –1.0 • Caption: Plots of hypothetical correlations Methods for Testing Hypotheses - The Correlational Method • Limitations of the correlational method – Cannot establish a causal relationship between one variable and another • Value of correlational method – Can be used when it is unethical to manipulate people’s experiences in an experiment – Allows an examination of multiple factors that combine to influence development Methods for Testing Hypotheses – Meta-Analysis • Meta-analysis examines multiple studies that address the same question and synthesizes the results to produce overall conclusions – When results of multiple studies converge Learning Objectives • What are the characteristics of cross• • sectional, longitudinal, and sequential research designs? What are the advantages and disadvantages of the cross-sectional and longitudinal designs? How does the sequential design resolve the weaknesses of these designs? Developmental Research Designs • Specialized research designs to study how people change and remain the same as they age – Cross-sectional designs – Longitudinal designs – Sequential designs Developmental Research Designs – Cross-Sectional Designs • Cross-sectional designs – Compares the performances of people of different age groups or cohorts • Cohort – group of individuals born at the same time – Provides information about age differences • Age effects – relationship between age and a particular aspect of development • Cohort effects – effects of being born a member of a cohort or a generation in a historical context Developmental Research Designs – Cross-Sectional Designs • Limitations of cross-sectional designs • – Age effects and cohort effects are confounded, or entangled – Do not reveal how people change with age Advantages of cross-sectional designs – Quick and easy to conduct – Can yield valid conclusions about age effects if the cohorts studied are likely to have had similar experiences Developmental Research Designs – Longitudinal Designs • • Longitudinal designs – Trace changes in individuals as they age Limitations of longitudinal designs – Age effects and time of measurement effects are confounded – Costly and time-consuming – Measurement methods may become obsolete – Participants are lost – Effects of repeated testing • Caption: Cross-sectional and longitudinal studies of development from age 30 to age Developmental Research Designs – Sequential Designs • Sequential designs – Combine the cross-sectional and the longitudinal approach and improve on both • Can reveal age effects • Can reveal cohort effects • Can reveal time of measurement effects Learning Objectives • What special challenges do developmental • • scientists face? How can scientists conduct culturally sensitive research? How do scientists protect the rights of research participants? Challenges in Developmental Studies • Conducting culturally sensitive research – Study samples of developing people from variety of ecological settings • SES is particularly important – Study different cultural and subcultural groups – Keep ethnocentrism from influencing one’s research • Belief that one’s own group and its culture are superior Challenges in Developmental Studies • Protecting the rights of research participants – Research ethics • Standards of conduct that protect research participants from psychological or physical harm –Informed consent –Debriefing –Protection from harm –Confidentiality