PSY 231 1st Edition Lecture 2Outline of Last Lecture I. About This CourseII. Limitations of Everyday ObservationOutline of Current Lecture II. Features of Many Research StudiesIII. Research Designs and QuestionsIV. Two Kinds of Questions that do not Address Cause-EffectV. Why Being Clear About Cause-Effect MattersVI. Questions that do Address Cause-EffectVII. Tools for Finding CausesVIII. What Makes Experiments SpecialCurrent LectureFeatures of Many Research Studies● Research Methods --guidelines for obtaining accurate, objective information● Special circumstances for observing-- experiments usually don’t take place in the flow of everyday life● Careful measurement--of the thing you want to learn aboutResearch Designs and Questions● Research questions ask something about the world● Research Design--plan for getting answers to the question○ Design depends on the kind of question● Co-Occurrence -- two events happen togetherTwo Kinds of Questions that do not Address Cause-Effect● Goal--Describe○ measure occurrence● Descriptive Research--some surveys, naturalistic observation● No way to predict● Goal--Predict○ measure co-occurrence● Correlational Research--two variables measured as they naturally occur together (co-vary)○ change together in predictable ways○ knowing about X, how reliably can you guess about Y?○ Predictiveness -- positive correlation● Co-Occurrence could mean…○ directionality problem--A changes B or B changes A○ Exercise causes people to weigh less or being heavy causes people to exercise less?○ Third variable problem-- some unmeasured factor(C) changes both B and AWhy Being Clear About Cause-Effect Matters● Vaccines = autism correlation study○ many people resisted vaccines○ Autism rates did not change when they stopped getting vaccinesQuestions that do Address Cause-Effect● Goal--Control○ measure cause and effect● Experiments-- the only research design that searches for causesTools For Finding Causes● Independent Variable --a possible cause of change in what people do○ two or more levels (present vs. absent)● A “science of causes” requires observing in action● Dependent Variable -- the behavior whose causes you want to learn aboutWhat Makes Experiments Special● We choose when/how to vary IV(independent variable)○ causes in action○ we can see IV affect DV (dependent variable)● Not all IV can be manipulated○ EX: sex, wealth, race, psychopathology● We try to hold all factors constant except for the IV○ only the IV can affect the DV● Experiments are
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