2. Psychology 101: General  Chapter 1Part 2 Scientific Method Instructor: Mark Vachon

3. The Scientific Method  Science is empirical  Science is gathering data that is observable and measurable  The Scientific Method: 1. Creating a theory 2. Forming a hypothesis 3. Testing the hypothesis 4. Drawing conclusions 5. Report results

4.  Theory: explains behaviors or events by offering ideas that organize what has been observed  Simplifies  Leads to clear predictions Example: low self-esteem contributes to depression  Hypothesis: testable prediction Example: people with high self esteem will score lower on a depression scale  Operational Definition: statement of the procedures used to define a research variable. Example: depression may be defined as a score on a test Theory & Hypothesis

5. Description Answers “what is happening?”  Case Studies  Surveys  Observation Descriptive methods will observe and describe, but not predict or explain

6. Correlation When one trait or behavior accompanies another, we say the two correlate. Correlation coefficient Indicates direction of relationship (positive or negative) Indicates strength of relationship (0.00 to 1.00) r = 0.37 + Correlation Coefficient is a statistical measure of the relationship between two variables.

7. or Correlation and Causation Correlation does not mean causation!

8. Experimentation  The only way to show causation  Experiments:  Manipulate factors that interest us  Other factors are kept under control  A controlled method of manipulating variables:  Independent Variable: what is manipulated  Dependent Variable: what is measured  If behavior changes when we vary an experiment factor, we know the factor is having an effect

9. Independent variable  Factor manipulated by the experimenter  Effect of the independent variable is the focus of the study Example: effects of breast feeding upon intelligence What is the Independent Variable? Breast feeding is the independent variable Independent Variable

10. Dependent variable  Factor that may change in response to an independent variable.  Usually a behavior or a mental process. Example: effects of breast feeding upon intelligence What is the Dependent Variable? Intelligence is the dependent variable. Dependent Variable

11. Experimental Groups How to control variables?  Experimental Group: receives the experimental treatment  Control Group: no experimental treatment  Compare the dependent variables  Groups need to be randomized

12. Experimentation A summary of steps during experimentation

13. Experimental Problems  Placebo Effect: belief in something is a powerful motivator!  Experimenter Effect: experimenter wants to get results!  To solve for these effects, go in “blind:”  Single: participants  Double: participants and experimenter