Developmental Research Methods PS Lecture 2
Outline of Lecture Theories, Hypotheses, Methods – the Big Picture of Scientific Psychology Ellen Langer’s Nursing Home Study - General Research Design Issues Warner Schaie’s Aging Study - Specific Developmental Designs in Later Adulthood Ethical Considerations in Developmental Research
I. The Scientific Method – The Official Story Theories Hypotheses Methods Data/Results
Darwin’s Real-Life Scientific Progression Interested as youth in “old earth,” earlier life forms Observations on voyage of HMS Beagle – how past species, fossils seemed to resemble present Idea of natural selection occurs to him creatively after reading Malthus on human famines – change comes through competition and selection of most fit Formally testing explanatory power of theory against natural observations and experiments (If evolution true, then what would we expect – ex. transition forms)
The Far Side Real History of Science and Research
Ellen Langer
II. Langer & Rodin (1976, 1977) Plant Study 91 residents, aged 65-90; 2 floors of nursing home One floor got a “personal control” treatment – emphasized making own decisions, choosing and caring for plant, go to movies, etc. Second floor got a “be happy” talk, told how staff would look after them well, given a plant that staff would take care of, told when to go to the movies Follow-up 3 weeks after: questionnaire, nurses’ ratings, behavioral measures Long-term follow-up 18 months later – health ratings, mortality
Results 3 Weeks Later - Percentages
Longitudinal Effects – 18 Months Later
Types of Research Design on Personal Control and Happiness – What Did Langer Use? Observational or Correlational Design Experiment Field Study
Correlational Designs Observational/Correlational Approaches: Why is the Langer study not a correlational design? Advantages and disadvantages of these? Naturally occurring variation in world No control and manipulation = not able to infer causality
Experimental Designs- Advantages and Disadvantages Why is the Langer nursing home study NOT an experiment? What are the advantages and disadvantages of experiments? Advantages: Control of all other variables through random assignment Disadvantages: Not necessarily representative of real world
Field Studies – Langer’s Research Why is the Langer study a field study? Way to address some of the problems of experimental designs But what might be some problems for a study like Langer’s in terms of actually inferring what causes what? group effects, nurses, particular home, etc.
Methods: Measurement Strategies for DV – What Did Langer Use? Questionnaires – Self-reports of happiness Interviews & Stories – Self-reports Systematic Behavior Observations – contest entry, nurses’ ratings Physiological Measures – e.g., heart rate Archival, Non-Obtrusive Measures – mortality stats, wheelchair tape
Evaluating Measures: Types of Reliability Inter-Observer Reliability Test-Retest Reliability Internal Consistency of Items on Questionnaires – Cronbach’s alpha
Evaluating Measures: Types of Validity Face Validity – reasonable questions on surface to neutral observer Predictive Validity – scores predict closely to another similar measure (nurse vs. doctor ratings) Construct Validity – how well scores fit into network of constructs specified by theory
III. Werner Schaie’s Seattle Longitudinal Study - Types of Developmental Designs Cross-sectional designs Longitudinal designs Sequential designs Meta-analysis
K. Werner Schaie ( )
Cross-Sectional Studies Most common study in aging research: Compare performance of younger vs. older adults on some task – e.g., intelligence tests Suppose they are different – what factors can explain this? Age, cohort, sampling, task x age?
Longitudinal Studies Follow same group of people over time Advantages: can measure change, follow individual variations over time Disadvantages: Practice effects Selective dropout Cohort-dependent results
Schaie’s Seattle Longitudinal Study – Comparative Data on Mental Abilities Across Lifespan
Longitudinal Sequential Designs What would such a study look like? Advantages: can examine cohort differences, can estimate selection effects Disadvantages: practice effects, selective dropout still are problems
Meta-Analysis Summarizes many different studies Provides a quantitative assessment of how systematic the effects are across many studies Depends on quality of research summarized
IV. Ethical Issues in Research on Elderly (or Anyone) Risk/Benefit Informed Consent Deception/Feedback Privacy/Confidentiality