1. Psychology as a Science
Chapter 1

2. The Scientific Attitude
Curiosity, skepticism, humility
Scientific attitude
Examine assumptions
Discerns hidden values
Evaluates evidence
Assesses conclusions

3. The Scientific Attitude
Limits of intuition & common sense
Hindsight bias – I knew it all along phenom.
9/11
What would you consider the climate of Antarctica?
Overconfidence
Convince ourselves we were almost right
What is the point farthest east in the US?

4. The Scientific Method Theories – organize and predict
Hypothesis – TESTABLE prediction
Operational definition – definitions and measures for a specific study
Strong hypotheses should be able to be replicated
Cycle of theoretical research (page 25, fig. 1.1)

5. Descriptive methods Case Study Survey Naturalistic Observation
Wording effects
Random sample
Represents population
False consensus
Naturalistic Observation

6. Correlation Studies
Correlation coefficient – statistical number that describes the strength of a relationship between two variables
Strongest correlations are 1 & -1
Means that one strongly predicts the behavior of the other
Use scatter plots and line of best fit to determine the strength of a correlation
Correlations of >.5 or <-.5 are consider at least moderately strong
We will talk about statistical significance later

7. Correlation Studies Correlation and causation
No matter how strong a correlation is, it doesn’t mean one variable causes the other!!!!!
Third factors can often be involved and muddy the ability to show causation
Causation arrow could point both ways
Cannot be used as proof!?

8. Correlation Studies Illusory correlations
Illustrations of believed relationships lead to unscientific conclusions
Need correlations based in data (math) not examples/case studies
We naturally look for patterns as human beings

9. Experiments
Experiment – investigator changes one or more variable (independent variable) to observe the effect on some behavior or mental process (dependent variable)
Seeks to control other important factors
Random sample
Sample size
Gives cause and effect if proper control of extraneous variables

10. Evaluating therapies
Experimental condition – people receive the treatment or one version of the independent variable
Control condition – closest approximation of “normal” conditions
Comparison with experimental condition
Contrasting in independent variable with EC

11. Evaluating therapies Double-blind procedure Random assignment
Placing subjects into EC or CC without subject or experimenter knowing
Controls placebo effect
Random assignment
Making sure that EC and CC are fundamentally the same
“Average” subject in EC should match average of CC
Larger sample gives a better chance of good grouping

12. Dependent vs. Independent variable
Independent variable – variable that experimenters change from EC to CC
This is the variable that is controlled/changed on purpose
Dependent variable – this is a measurable difference between a factor in the EC and CC because of the change in the independent variable
How it is measured is the same in both conditions
Difference should be due to change in variable from one condition to the other

13. Measures of Central Tendency
Mean = Average
Add up each score (DV) and divide by the total number of scores
Ex. 75, 80, 90, 80, 85, 60
470 ÷ 6 ≈ 78.3
Median = the middle score
75, 80, 90, 80, 85, 60
Median is 80 (if even number of scores (ex. 6) then mean of middle two)
Mode = most often
Which score is repeated the most?
80 is the mode
60, 75, 80, 80, 85, 90

14. Measures of Variation Data is better when it is clumped together Range
The more spread the worse the correlation
Range
Largest – smallest = range
e.g = 30
Standard Deviation
How far from the middle is “normal”
Two standard deviations is OK
Bell curve
Outside two deviations = outlier (weird)
SD2
SD1

15. What do I Know Now? Reliable – can I apply my finding to everyone
Representative sample
Low-variation in scores/observations
Large sample size
Significant – how confident am I in the results
If:
Averages are reliable (see above) &
The difference between the EC & CC averages is large
Then the finding is significant
Large is relative to the scores

16. Extra Stuff Do experiments work? Can result be generalized?
What are ethics in research?
Ethical standards
Informed consent
Freedom from harm
Debriefing
Justified use of deception
Animal research
Human research
Values in psychology.