Research Methods in Developmental Psychology Michael Hoerger Observation  Hypothesis generation  Laboratory Observation: Parent-child interactions, marriages, intrusive interviews, attachment style  Naturalistic observation: bullying, ADHD Case Study  Used to gain detailed information on a single or small number of cases, commonly used in medicine and clinical psychology: rare events, new events, complex events Correlation Correlation  r = Strength of relationship between two variables (-1 to +1)  What is a “big” correlation?     Reliability: r = .90 IQ tests: r = .50 to .90 Personality research: r = .30 Life/death: r = .01  Problem: Correlation ≠ Causation due to 3rd variable problem and directionality problem  Solution: Methods and argument Cross Lagged Panel Design (or “Cross lag panel” or “Cross panel lag”)  Look at correlation between two variables over time  Does X correlated with changes in Y?  Smoking at Time 1 causes increased mile time at Time 2 Age 20 Smoking Cigarettes r = -.05 r = .10 Time to run a mile Age 40 Smoking Cigarettes r = .10 r = .30 Time to run a mile  Look at correlation between two variables over time  Does X correlated with changes in Y?  Maternal depression at Time 1 causes increased behavior problems at Time 2 Maternal Depression Maternal Depression Maternal Depression Child Behavior Problems Child Behavior Problems Child Behavior Problems THIS DRUG HAS HELPED TO TREAT: HAY FEVER, ASTHMA ATTACKS, ANXIETY, PAIN, ULCERS, ENURESIS, WARTS, ARTHRITIS, MALIGNANT TUMORS, DIABETES, NARCOTIC WITHDRAWAL, INSOMNIA, COLDS, AND INATTENTIVENESS Experiment “id!”  Independent variable: the manipulation; different conditions or groups  Alcohol vs. placebo; CBT vs. waitlist  Dependent variables: depends on the independent variable; the outcome variable  Age at death; depression; liver functioning  Problem: Participants must be similar across IV groups  Solution: Random assignment Survey  Interviews, questionnaires, tests  Used for correlational studies or as outcome (DV) measures in experimental studies  Highly efficient  Can be anonymous  Problems: Wording, Response bias (e.g. social desirability)  Solutions: Design with care Online Research  Most surveys and some experiments can be run on the web (e.g. priming studies)  Benefits: most efficient, useful for screening large samples  Risks: Lower experimental control, random responding, technical problems, nonrepresentative sampling, ethics  http://funpsych.com example Physical Measures  Physiological: changes in functioning  Galvanic skin response (sweating), pupil dilation, heart rate  Physical: walking speed, eye movement, speed of responding, height, weight  Neurological: neurotransmitter levels, brain structure  Benefits: reliability of measurement  Risks: expensive, often fail to provide new information, low correspondence Cross-Sectional Research  Groups differ by age  Compare children to teens to young adults to older adults  Differences are presumed to be the result of age  Older people are slower due to aging  BUT differences may simply be due to contextual factors, such as the era each group was born in  OR older people are slower due to differences in nutrition growing up Longitudinal Research  Follow one group over time to what changes with age  Problem: expensive, bias due to dropout Cross-Sequential Research  Combines cross-sectional and longitudinal research Michael Hoerger To cite this lecture:  Hoerger, M. (2007, January 10). Research Methods in Developmental Psychology. Presented at a PSY 220 lecture at Central Michigan University.