Methods of Psychological Research

1. Methods of Psychological Research Module 2

2. Learning Objectives What methods are used by psychological scientists? Why are scientific methods important? Why is it important to devise subtle measures of studying behavior? Are there problems with self-report? What are the ethical issues involved in conducting research with human & animals?

3. Scientific Methods Theory A framework of interrelated ideas that can be used to understand a variety of phenomena E.g., evolutionary theory Hypotheses A specific prediction that is derived from the theory E.g., gender differences in mate selection

4. Steps in a Scientific Investigation Form a testable hypothesis Design a study Laboratory research Field research Operationalization of variables Collect data Analyze data and draw conclusions Do your findings support your theory? Report findings

5. Psychological Measurement Self-report (interviews, surveys, diaries) Rate how attractive you are (1-8 scale) Social desirability Lack of self-awareness Behavioral Observation Bathroom behavior (handwashing) May infer internal states (prejudice) Archival Research (violence prediction)

6. Descriptive Research Case studies In depth description of a single individual Surveys Description of a population based on a sample Naturalistic Observation Observe behavior in its natural environment No manipulation of variables Study of judges� nonverbal behavior Effect of being observed

7. Correlational Research The observation or measurement of two variables to see whether they are related Correlation coefficient tells you the direction and the magnitude of the relationship Range from -1 to +1 Positive correlations � as one variable increases, so does the other variable Negative correlations � as one variable increases, the other decreases Zero means there is no relationship

8. Correlation and causality Correlation does not equal causation Does A cause B or does B cause A? Consumption of violent television and aggression are positively correlated Third variable problem: Does C cause both A and B? Ice cream consumption and murders are positively correlated Toaster ownership and teenage pregnancy are negatively correlated

9. Experiments Allows statements about causality Features of an experiment Manipulation of an independent variable IV = event varied by experimenter to see its impact on another variable Random assignment to groups Measurement of a dependent variable Do controlled changes in the IV cause changes in the DV

10. Anger management experiment Experimental and control groups IV = training vs. no training DV = Aggression while playing video game Extraneous variables Variable other than IV that may affect DV Importance of random assignment Confound = Variable that systematically varies with IV that may affect DV

11. Common research flaws Demand characteristics Defendant attractiveness studies Experimenter expectancy effects Maze smart vs. maze stupid rats Sampling bias (Surveys) Biased selection Larger samples vs. smaller samples M&M distribution 30% broan 20% red and yellow 10% green, orange, and blueM&M distribution 30% broan 20% red and yellow 10% green, orange, and blue

12. M&M data (Fall 2005)

13. M&M data (Fall 2005)

14. M&M data (Fall 2005)

15. M&M data (Fall 2005)

16. M&M data (Fall 2005)

17. Skittles data (Spring 2005)

18. Skittles data (Spring 2005)

19. Skittles data (Spring 2005)

20. Skittles data (Spring 2005)

21. Ethical considerations Human participants Informed consent Analysis of cost/benefits by IRB Animal subjects Strict regulations for care and treatment Cost/benefit analysis Some studies cannot be done with people