1. Lecture 2 The Science of Psychology

2. Today’s Outline Critical Thinking & Science Psychological Methods
Types of data
Self report
Observation
Research Design
Archival
Correlational
Longitudinal
Experimental

3. Methods of Psychology: Scientific Method
Science starts with an attitude and a desire for the truth
Systematic empirical study of phenomena
__________: keep the bias out, include all data and information even if it doesn’t “fit”
__________: based on observable events
__________: must be measurable

4. Short Video What was the study? Did people believe it?
What’s a placebo?
Why do placebos work?

5. Problems with Common Sense
People see some parts of the world and miss others
due to preconceptions, ability, attention, etc.)
People notice those things that fit preconceptions
People often believe to be true whatever feels good

6. The Scientific Method
To develop theories about the world and to test those theories using observations
Theory: An explanation
Scientific theory is backed by data
The scientific process
Is self correcting (theories are tested, then revised, then tested)
Theories are _________
The process is objective and public

7. The Science of Psychology
Separating anecdotes, folk wisdom and advice from data and conclusions!
Scientific Research is…
Formulating _______________
Testing __________ using the scientific method
Interpreting the results
Communicating the results --- realistically

8. The goals of science Description: What happens?
Prediction: When does it happen?
Explanation: Why does it happen?
Theory
Causal Inferences
Intervention/Application: What could be done to help?
These all build on each other

9. Self Report Self-report methods: ask participants to tell you
Interviews
Questionnaires
Daily diary methods

10. Observational Data Observational Data Observations in natural settings
Laboratory-based observation

11. Research Designs Archival – digging through the vaults…
Correlational research – when one goes up, what happens to the other?
Longitudinal research – how do things relate over time?
Experimental research – if one is changed, what happens to the other?

12. Archival Research
Researchers examine existing data that may or may not have been intended for research
Harker and Keltner (2001) used yearbook pictures to predict marital outcomes 30 years later

13. Archival Results
Smiling at age 20 predicted:

14. Correlational Research
Assess the naturally occurring associations among two variables
Positive correlation
rewards are positively associated with satisfaction
Negative correlation
conflicts are negatively associated with satisfaction

15. Correlational research
The statistical concept of a “correlation coefficient (r)”
Perfect positive
correlation (+1.00)
No relationship (0.00)
Perfect negative
correlation (-1.00)

16. Correlation does not imply causation!
Three possible interpretations of any correlation

17. Pros and Cons of Correlational Research (descriptive)
Advantages
Disadvantages

18. Longitudinal Research
Data collected at 2 or more time points
Associations among variables across time
How are feelings of love across time associated with divorce?

19. Longitudinal Research
Associations among variables within a day
How does a partner’s behavior during the day influence feelings of commitment at night?

20. Pros and Cons of Longitudinal
Advantages
Disadvantages

21. Experimental Research
Manipulate one variable to see if it causes changes in another variable.
Does arousal lead to greater liking? A B

22. Testing the WHATs and WHYs
1:1 correspondence
If you pour x into y, you know x caused the explosion
If you pour x and z into y, you don’t know what caused the explosion
Random Assignment
In large enough samples, characteristics will be equally distributed

23. Experimental: Video Games & Violence
What is an independent variable?
What is a dependent variable?
What is the point of experiments?
What is random assignment?
How are differences controlled?

24. Pros and Cons of Experimental
Advantages
Disadvantages