Experimental Methods Sept 13 & 14 Objective: Students will be able to explain and evaluate the research methods used in psychology. Agenda: 1. CBM 2. Reading Check 3. Finish Approaches notes 4. Research Methods notes 5. HW: Research methods chart, essay

Reading Quiz 1. The belief that after an outcome of an event that one could have predicted that particular outcome. 2. Testable prediction usually implied by a theory. 3. Fair representation of a population because everyone has an equal chance to participate. 4. The two elements in an experiment – one is the part being manipulated, while the other is being measured. (Must be in the correct order) 5. Clear statement of procedures which allows the process to be replicated.

Basic Ideas  Goal : Describe, predict, control & explain behaviors  Theory  Hypothesis  Variables  Sampling

Naturalistic Observation  Watch ONLY  Used if other methods would be misleading  Large amounts of data  Problems:  Change if known being observed  See what expect

Case Studies  Individuals/small groups  Interviews, transcripts, tests  Neuropsychology Uses: -Raw material -Particular people -Testing ground Limitations: -Limited evidence -Not representative

Surveys  Uses:  Large amounts of data  Limitations:  Validity  Wording  Honesty  Distortion

Experimental Method  Controlled by researcher  Independent variable  Item being manipulated  Dependent variable  Item being measured and affected  Control group  Receives no treatment  Experimental group  Receives treatment Operational Definition – define exact steps/methods used in research

Experimental Method cont’d  Confounding variable  Any factor that affects the dependent variable in addition to or instead of the independent variable  Random variable  Uncontrolled/uncontroll able factors  Reliability  Validity  Experimenter bias  Unintentional effect that researcher may have on results  Placebo effect  No benefit but helps because believe it will  Double blind design  No one knows who gets what

Ex Post Facto  Manipulation has already occurred  Use comparison groups  Use groups that are in tact  Explores possible causes and effects  Focuses first on the effect, then attempts to determine what caused the observed effect

Statistics  Measures of central tendency – typical scores  Mean  Median  Mode  Measures of variability  Range  Standard deviation Calculate the mean, median & mode for the following numbers 4, 3, 7, 2, 5, 4, 4, 8

Correlation  Correlation coefficient  Positive Correlation  Negative Correlation  Correlation v. Causality

experimentcase study naturalistic observation survey Correlational studies description weakness strength scenario in which this method could be used

Essay Psychologists use a variety of research methods to study behavior. Three of the main research methods used are  Case study  Correlational Study, and  Experiment A. Discuss one advantage of each research method mentioned above. B. Discuss one disadvantage of each research method mentioned above. Pretend you are a psychologist who will use each of the three research methods – case study, correlational study, and experiement – to determine the effect of taking vitamin J on improving memory. C. For each method listed above, explain a key characteristic of the basic approach you could use to reach a scientific conclusion about the relationship between taking vitamin J and improving memory. You need not design a complete study.