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Thinking Like a Psychologist Part 33 1 / 3. PSYC 200 Week #9. Agenda. Roll call Essay #2 (missing several) APA Mastery Test – see me if questions Review Control, Research Methods, and more Intuitions Test Probability, Chance, and the Popular Image of Psychology. Review.
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Thinking Like a Psychologist Part 33 1/3 PSYC 200Week #9
Agenda • Roll call • Essay #2 (missing several) • APA Mastery Test – see me if questions • Review • Control, Research Methods, and more • Intuitions Test • Probability, Chance, and the Popular Image of Psychology
Review • Does correlation prove causation? Why or why not? • What is the principle of faslifiability? • What are the problems with testimonial evidence?
Control • Necessary to make causal inferences and rule out alternative explanations • When a researcher holds everything in 2 (or more) different situations constant except for a particular variable • Requires that we separate and individually control variables that may naturally occur together • Then if the outcome changes, the only explanation is the variable that changed… • Outcome = Dependent Variable • Manipulated variable = Independent Variable
Control (cont’d) • The Control Group • A group of participants that receives no (or alternative) treatment • Why important? • Examples of importance • Clever Hans • Facilitated Communication • Separation of Variables • Must rule out alternative explanations; therefore must create artificial situations where variables that naturally occur together are teased apart.
Naturalistic Observation Quasi-Experimental Survey Relational Research Field Study Experimental Research Methods • There are 6 basic categories of scientific method that virtually all research falls into Research Non-Experimental Experimental
Research Methods –Naturalistic Observation • Addresses most basic scientific question: “What is out there?” • Requires operational definition of events to be observed • Observer must be unobtrusive, and design must be nonreactive
Research Methods –Field-Based Research • Like naturalistic observation, conducted in real-world settings • Goal is to establish natural relations among events • Observer must be unobtrusive, but methods are intentionally reactive
Research Methods –Survey Research • Appropriate to the study of private behaviors • Two primary styles: • Interviews (structured/unstructured) • Questionnaires (structured/unstructured)
Research Methods –Relational (Correlational) Research • Goal to verify systematic (usually linear) relations among events • Strengths/directions of relations • generally expressed in form of correlation coefficient (rxy)
Research Methods –True Experiment • Goal: to establish a cause-effect relationship among events • Does low-fat diet cause decrease in cancer risk? • Does exposure to violent video games cause increase in violent behaviors? • Does spaced study cause increase in memory accuracy and retention? • Do genetic variations cause sexual preference?
Research Methods –True Experiment • Requires: • random assignment of participants to at least two equivalent conditions • manipulation of one factor (independent variable, or IV) in one condition (experimental), leaving it unchanged in other condition (control) • measurement of one other factor in both conditions (factor called dependent variable, or DV; measurement instrument called dependent measure, or DM)
Research Methods –True Experiment • Concludes: • if groups are NOT equivalent with respect to DV, and • if the difference between the groups is so big it probably did not happen by chance, then • manipulation of the IV caused the difference in the DV
Research Methods –Quasi-Experiment • Goal also to establish cause-effect relations among events • Required when random assignment is not possible, because • must use pre-existing groups, or • IV impossible to manipulate directly, or • IV unethical/illegal to manipulate directly
Research Methods Review • Name 6 categories of scientific research • Which method of research can be used to establish cause and effect relationships?
Converging Evidence • Gradual Synthesis Model • Great Leap • Remember, the goal of science is really to get less and less WRONG.
Multiple Causation • Most phenomena are caused by multiple (not just one event) • Examples? • There’s usually no “magic bullet” or “missing key”