Human Growth and development Winter 2011-2012

1. Human Growth and developmentWinter 2011-2012 Melissa Scholten, M.A.

2. Chapter 1 • Main points: • How should we think about development? • What is the science of Life-Span Development? • How is development studied? • What special challenges do developmental scientists face?

3. 1.1 How should we think about development? • Defining Development • Conceptualizing the Lifespan • Framing the Nature/Nurture Issue • Grasping the Ecology of Development

4. Defining Development • Development involves systematic continuities and changes from conception to death in three domains • Physical development- growth of body, physiological change • Cognitive development- changes to perception, language, learning, and memory • Psychological development- changes in personality, emotions • Growth- physical changes from conception to maturity • Biological aging- deterioration of organisms • Aging- positive and negative changes in maturing organism • Development of change involves both gains and losses

5. Conceptualizing the Lifespan • Periods of lifespan: prenatal, infancy, preschool, middle school, adolescence, early adulthood, middle adulthood, late adulthood • Age grade (age stratum)- status, roles, privileges, and responsibilities based on one’s age group • Legal definitions of age boundaries (e.g. adolescence and adulthood) vary by state • Culture impacts the recognized periods of the lifespan • Eskimo simply distinguish between boy/girl and man/woman • !Kung define old in terms of functioning; not age • A rite of passage is a ritual marking passage from one status to another • Jewish bar or bat mitzvah • Hispanic-American girl quinceanera at age 15

6. Conceptualizing the Lifespan • Age norms- expectations based on age • Social clock- sense of timing for life transitions • “Off time” (socially age inappropriate) events have more negative impact • Subcultural differences exist in age grades, age norms, and social clocks • Society is diverse with respect to race, ethnicity, or socioeconomic status • Individuals from lower- income families tend to reach adulthood milestones earlier than those from middle- and upper- class families

7. Conceptualizing the Lifespan • Meaning of childhood, adolescence, and adulthood change with historic period • In Western society, during the 17th century, children came to be viewed as distinct from adults • In medieval times, children were expected to grow up as fast as possible • Adolescence was recognized as a separate period in the late 19th and early 20th centuries • The need for an educated workforce and compulsory schooling helped to lead to adolescence being viewed as a distinct period of life • Emerging adulthood is the time from age 18-29 • Middle age emerged as a distinctive state of life in the 20th century (Exploration Box on emerging adulthood)

8. Conceptualizing the Lifespan • Meaning of childhood, adolescence, and adulthood change with historic period • Some characterize middle age as a time of crisis, but it tends to be a time of good health, peak cognitive function, and high satisfaction • Old age also became a unique time period in the 20th century • In the past, relatively few individuals lived to old age, in part because so many people died in infancy • The average life expectancy (average number of years a newborn is expected to live) is 81 for a white female, 77 for a black female, 76 for a white male, and 70 for a black male • Racial differences in life expectancy have been declining while differences based on socioeconomic status have been widening • While today’s elderly are healthier than in the past, many do have chronic diseases and disabilities and require support • Development must be viewed in historical, cultural, & subcultural context

9. Framing the Nature/Nurture Issue • The two sides of the debate • Maturation (nature)- biological unfolding of plan contained in genes (heredity, material from parents) • Genetically influenced maturation guide us through many of the same changes at about the same time • Individual heredity endowment makes each person unique • Environment (nurture)- external physical and social conditions, stimuli, and events • The nurture side- emphasizes learning (relatively permanent changes from experiential influences) • Development is due to interplay between nature and nurture • Both social (e.g. patrilineal cultures) and genetic factors both influence levels of aggression

10. Grasping the Ecology of Development • Bronfenbrenner’sbioecological model • Stresses how biology and environment interact to produce development • Four environmental systems influence and are influenced by the developing person • Microsystem- immediate physical and social environment individual interacts with face-to-face, involves reciprocal influence • Mesosystem- linkages between two or more microsystems • Exosystem- linkages involving social settings that individuals do not directly experience (e.g. parent’s work day) but still influence behavior • Macrosystem- larger culture (shared understanding and way of life of a people) in which other systems are embedded • Chronosystem- people and environments occur in particular time frame and unfold in a particular pattern • Models suggest that study of development will not be easy • Influence of factors like person, context, time, and processes difficult to separate

11. 1.2 What is the Science of Lifespan Human Development? • Goals of Study • Early Beginnings • The Modern Lifespan Perspective

12. Goals of Study • Goals of Study • Description of human development • Normal (typical) development • Individual differences • Explanation of human development • Why humans develop as they do • Why some humans develop differently • Optimization of human development • How can humans be helped to develop in a positive direction (i.e. how can capacities be enhanced?)? • Applied research on optimizing development should be based on evidence-based practices (i.e. grounded in research and demonstrated to be effective)

13. Early Beginnings • Baby biographies • Late 19th century scholars who observed and recorded the development of their own children. • Charles Darwin perhaps the most influential baby biographer • Darwin believed that infants share characteristics with nonhuman ancestors • Darwin’s evolutionary perspective influences early theories of development (Exploration Box on Darwin’s baby biography on the development of anger in his own son). • Methodology poor • Biographers emphasized different aspects of development • Observers not objective • Observed only a single child • G. Stanley Hall • Cited as founder of developmental psychology • First President of American Psychological Association • Collected data on the “content of children’s minds” • Wrote Adolescence (1904) in which that time of life was viewed as one of “storm and stress” • Book led to modern inaccurate notion of teenagers as emotionally unstable • Wrote Senescence (1922), which was an analysis of how society treats (mistreats) older members

14. The Modern Perspective • Gerontology- study of aging and old age • Lifespan perspective- focus on infancy through old age • Key text themes • Development is a lifelong process • Development is multidirectional (different aspects of functioning have different trajectories of change) • Development involves both gain and loss • Life-long plasticity in human development • Plasticity- capacity to change to positive and negative experiences • Plasticity continues into later life • Neuroplasticity- brain’s capacity to change in response to environmental experiences throughout the lifespan • Physical exercise and mental stimulation can change neurochemistry, create a new connections among neurons (even in the aging brain)

15. The Modern Perspective • Development is shaped by its historical/cultural context • Great Depression impacted parental behavior and the development of children and adolescents • As societies change, developmental experiences change (e.g. modern children hold more individualistic as opposed to communal values) • Development is multiply influenced (biology and experience) • Now talk of developmental science rather than developmental psychology • Understanding development requires multiple disciplines (e.g., biology, history, economics)

16. 1.3 How is Development Studied? • The Scientific Method • Sample Selection • Data Collection • The Case Study, Experimental, and Correlational Methods • Developmental Research Designs

17. The Scientific Method • Scientific method- an attitude of systemic observation • Believe the data • Helps to weed out flawed ideas • Theory- set of concepts and propositions intended to describe and explain some experience • Hypotheses- predictions generated to test theory • Good theories should be • Internally consistent (i.e. not generate contradictory hypotheses) • Falsifiable- (can be proven wrong) • Supported by data- (i.e. have predictions confirmed by research results)

18. Sample Selection • Research sample- group being studied • Population- larger defined group from which sample is drawn • Random sample- a portion of the population to be studied • Means of drawing random sample from population increases confidence in the representative nature of the sample and makes generalization possible

19. Data Collection • Three major methods of collection are verbal reports, behavioral observation, and physiological measures • Verbal reports • Often standardized interview, questionnaires, or tests • Cannot be used on infants, those who cannot read • Age differences in ability to comprehend questions may occur • Respondents may falsely present themselves in positive manner • Behavioral observations • Naturalistic observation- behaviors observed in everyday life • Greatest advantage is that techniques study everyday life • Three limitations: some behaviors occur infrequently to observe; difficult to pinpoint cause; presence of observer may influence behavior • Structured observation- researcher creates conditions to elicit a behavior • Can study behaviors rare neutral settings • Concern about ability to general to natural settings

20. Data Collection • Physiological measures • Assess physiological responses (e.g. hormone levels, heart rate) • Functional magnetic resonance imaging (fMRI)- brain-scanning technique using magnetic forces and measuring blood flow • Can determine which part of brain involved in cognitive activity • Difficult to fake • Sometimes unclear as to what is being assessed • Multiple approaches used to study behavior (Exploration Box on the three approaches to studying anger and aggression)

21. The Case Study, Experimental, and Correlational Methods • The case study • In-depth examination of an individual (or small group) • Multiple sources of information (e.g. , observation, interview, testing) • Useful in studying people with rare conditions • Can be a good source of hypotheses • Conclusions cannot be generalized

22. The Case Study, Experimental, and Correlational Methods • The experimental method (Friedrich and Stein study on television shows and violence used as an example) • Independent variable- manipulated by experimenter (Friedrich and Stein, type of television show watch). • Dependent variable- behavior affected by independent variable (Friedrich and Stein- aggressive behavior) • Freidrich and Stein results: children who were already relatively aggressive and watched more violent television became more aggressive • Three critical features of any true experiment • Random assignment to experimental conditions ensures groups similar to each other • Manipulation of independent variable needed to establish cause • Experimental control- hold factors constant • Experiments: strength • Can be used to determine cause • Experiments: limitations • Do not hold true in real world • Ethical concerns (i.e. cannot conduct experiments on certain issues) • Quasi-experiment- nonrandom assignment to treatment groups

23. The Case Study, Experimental, and Correlational Methods • The correlational method • Correlational coefficient assesses extent that individuals’ scores on one variable are systematically related to scores on another • Huesmann and colleagues correlational study on television viewing and aggression • Involves calculation of correlational coefficient • Correlational coefficient (r ) score (extent to which scores on one variable are associated with scores on another variable) with ranges from +1.0 to -1.0 • High positive (+) correlation indicates the variables vary together in same direction (e.g., +0.9) • High negative (-) correlation indicates the variables vary together in opposite direction (e.g. -0.9) • Correlation near 0 indicates no relationship between variables

24. The Case Study, Experimental, and Correlational Methods • The correlational method • Alternative explanation to positive correlation between aggression and watching violent television (i.e. violent television causes aggression) • Direction of causality may be reversed (e.g. being aggressive may cause one to watch violent television) • Third variable may cause observed association (e.g. peer rejection causing violence and more violent television viewing) • Ambiguity means that a correlation cannot be used to establish cause • Numerous studies with convergent findings best way to establish cause/effect relationships • Meta-analysis- study in which results from multiple studies is synthesized • Meta-analysis results indicate that watching violent programs is related to roughhousing and more serious violent displays

25. Developmental Research Designs • Cross-sectional designs • Cross-sectional designs study different age groups (cohorts) measured at same time • Cohort is a group of individuals born at the same time (either the same year or within a span of years) • Cross-sectional design- provides information about age differences • Age and cohort effects and limitations to cross-sectional designs • Age effect- relationships between age and a particular aspect of development • Cohort effect- effect of being born in one particular historical context • Age and cohort effects are confounded and entangled (Exploration Box on cohort effects and Baby Boomers) • Cross-sectional designs observe an individual at only one point so they do not measure development of the individual • Advantages of cross-sectional designs • Quick and easy

26. Developmental Research Designs • Longitudinal design- studies same group (cohort) measured repeatedly • Longitudinal design provides information on age changes versus age differences and the direction or path of change • Limitations of longitudinal designs • Time of measurement effects- historical events and trends’ effects on development • In longitudinal designs, time of measurement effects and age effects are confounded • Unsure if change is due to aging or the result of sociocultural effects • Method is costly and time-consuming • Measure become dated • Loss of participants leads to smaller, less representative sample • Participants can be affected by repeated testing • Although both cross-sectional and longitudinal designs have weaknesses, they are both valuable research tools

27. Developmental Research Designs • Sequential design- the best of both worlds • Sequential designs combine cross-sectional and longitudinal approaches • Advantages of sequential designs • Can identify age-related trends regardless of cohort • Can identify cohort effects • Can identify time of measurement effects • Limitations of sequential design • Method extremely costly and complex

28. What Special Challenges Do Developmental Scientists Face? • Conducting Culturally Sensitive Research • Protect the Rights of Research Participants

29. Conducting Culturally Sensitive Research • Ecological setting can influence development • Must consider socioeconomic status (SES) status in society that includes occupational prestige, education, and income • Growing up in poverty or affluence will influence development • Must study individuals from different subcultures and cultures • Researcher must keep own cultural values from biasing perceptions • Ethonocentrism- belief that own group and culture are superior may creep into designs, procedures, and measures • Researchers may judge minority children and adults labeled as “deviant” versus “different: • Cannot assume that all members of a culture or subculture are alike psychologically

30. Protect the Rights of Research Participants • Research Ethics- standards of research conduct that researchers are ethically bound to honor • Study reviewed in Exploration Box 1.3 addressed several ethical issues • Ethical issues often arise in developmental research • Ethical guidelines established by different groups • American Psychological Association and Society for Research in Child Development guidelines • Human-subjects review committees (Institutional Review Boards)

31. Protect the Rights of Research Participants • Investigator’s ethical responsibilities • Weigh potential benefit and potential risk • Respect rights of participants by • Allowing participant to make informed and uncoerced decision about taking part in the study • Debriefing after completion of the study • Offering protection from harm • Treating information as confidential • Informed consent • Informed about all aspects of research that might affect participation • Those studying “vulnerable” populations must obtain informed consent from participant and someone who can decide on their behalf • Age (young children= lack of language, old age= possible dementia)

32. Protect the Rights of Research Participants • Investigator’s ethical responsibilities • Debriefing • Tell participants about purpose of study in advance • In cases where knowledge of the study would impact response, debriefing may occur after the study • Protection from harm • Researcher may not harm participant physically or psychologically • If harm likely, then another way of answering the question should be explored • If participant is harmed, researcher must take steps to undo harm • Confidentiality • Keep collected information confidential • Medical records now particularly well protected • Participants must give explicit permission to have information about them be shared