1. Chapter 2 Psychology’s Scientific Method
RESEARCH METHODS
Chapter 2
Psychology’s
Scientific Method

2. 4 goals of psychology Describe behavior Predict behavior
Explain behavior
Control behavior

3. 5 steps of the Scientific Method
Observing some Phenomenon
Formulating Hypotheses and Predictions
Testing through Empirical Research
Drawing Conclusions
Evaluating the Theory

4. 5 STEPS OF THE SCIENTIFIC METHOD
1. Observing some Phenomenon
Asking questions
Variables
2. Formulating Hypotheses and Predictions

5. 5 STEPS OF THE SCIENTIFIC METHOD
3. Testing through Empirical Research: Choose your research method
Descriptive Research: describes some phenomenon
Naturalistic Observation
Survey/ Interview
Psychological/ Physiological Tests
Case Study
Archival Research
Correlational Research: shows relationships
Experimental Research: shows cause and effect

6. 5 STEPS OF THE SCIENTIFIC METHOD
3. Testing through Empirical Research: Choose your research design
(NOT for Experimental Research)
Cross-sectional: Study participants of different age groups at the same time.
Advantage: quicker, less costly
Disadvantage: cohort effects, sample variability
Longitudinal: Study a particular group of participants over a prolonged period of time.
Advantage: more in-depth investigation, shows change over time
Disadvantage: more costly, dropout/death

7. 5 STEPS OF THE SCIENTIFIC METHOD
4. Drawing Conclusions
Replication
Descriptive/Inferential Statistics
5. Evaluating the Theory
Meta-analysis
Submitting results for publication

8. Introductory Terminology for Scientific RESEARCH
Variable: Any measurable condition that is controlled/observed in a study; anything that can change.
Theory: A broad idea or set of closely related ideas that attempt to explain observations and to make predictions about future observations.
Hypothesis: An educated guess that derives logically from a theory; a prediction that can be tested.
Operational Definition: An objective description of how a variable is going to be measured and observed.
Participants or subjects: The organisms whose behavior is systematically observed in a study.

9. Research Methods Descriptive Research: Naturalistic Observation
Survey/Interview
Case Study
Archival Studies

10. Naturalistic Observation
Description: Observing the participant in their natural habitat without interaction
Advantages
Disadvantages
Realistic picture of behavior
Good to start when little is known about a phenomenon
Difficult to remain unnoticed or unobtrusive
Time consuming

11. Survey/Interview
Description: Use of questionnaires to gain insight on an individual’s attitudes or beliefs
Advantages
Disadvantages
Gathers data of difficult to observe behaviors
Large sample size
Cost effective
Relatively easy
Wishful Thinking
Memory Lapses
Social Desirability Bias
Response Set
Wording Effect

12. Case Study
Description: An in-depth investigation on an individual or cohort (small group)
Advantages
Disadvantages
In-depth investigation
Helps formulate theories
Unique cases
Subjectivity
Researcher bias
Lack of generalizability

13. Archival research
Description: Extracting evidence from original records or other researcher’s findings
Advantages
Disadvantages
Researcher can not change data
Cost effective
Researchers have little to no control over information
Credibility of sources

14. Research Methods
2. Correlational Research

15. Correlational Research
Research that examines the relationships between variables, whose purpose is to examine whether and how two variables change together.
There is NO manipulation of variables
CANNOT imply a cause and effect relationship between the variables

16. Correlational Research
CORRELATION DOES NOT EQUAL CAUSATION!

17. Correlational Research
A local police chief in a small Midwestern town finds that as ice cream consumption increases, the crime rates increases. As people eat less ice cream, the crime rate decreases.
The police chief concludes that ice cream causes crime.
Scientists have linked television-watching with childhood obesity. According to a study in the Journal of the American Academy of Pediatrics, the degree of obesity rises 2 percent for each hour of television viewed per week by those aged 12 to 17.
Scientists conclude that TV watching makes you obese.

18. CORRELATIONAL research
Third variable problem: The circumstance where a variable that has not been measured accounts for the relationship between two other variables.

19. Correlational Research
Research study designed to determine the degree to which two variables are related to one another
When two variables are related to each other, they are co - related
A correlation is the numerical index of degree of relationship
Correlation are expressed as a number between 0 and 1
Can be negative or positive (-1 to +1)
Numbers closer to 1 (+ or -) indicate a stronger relationship
A correlation exists when two variables are related to each other.
The correlation coefficient is a numerical index of the strength and direction of association between two variables.
A correlation is expressed as a number between 1 and 0, and the number may be positive or negative.
The closer to 1 the number is, whether +1 or –1, the stronger the relationship between the variables…for example, a correlation of .17 is pretty weak, while a correlation of -.89 is pretty strong.
The positive/negative dimension of the correlation coefficient expresses the direction of the relationship. If two variables are positively correlated, they co-vary in the same direction…as scores on one variable go up, scores on the other variable go up too…if two variables are negatively correlated, the variables co-vary in the opposite direction…as one goes up, the other goes down.

20. Correlational Research

21. CORRELATIONAL research
How to read a Correlation Coefficient:
Correlation Coefficient: A statistical measure of the relationship between two variables.

22. CORRELATIONAL research
Strength

23. CORRELATIONAL research
Direction

24. CORRELATIONAL research
POSITIVE CORRELATIONS
As the value of one variable increases (or decreases) so does the value of the other variable.
The closer the correlation coefficient is to +1.0, the stronger the relationship.
A perfect positive correlation is +1.0
Direct relationship
Height
Weight

25. CORRELATIONAL research
NEGATIVE CORRELATIONS
As the value of one variable increases, the value of the other variable decreases.
The closer the correlation coefficient is to -1.0, the stronger the relationship.
A perfect negative correlation is - 1.0
Inverse relationship
Temperature
Sweater Sales

26. CORRELATIONAL research
ZERO CORRELATION
There is no relationship whatsoever between the two variables.
The closer the correlation coefficient is to 0, the weaker the relationship.
No relationship
Hours Spent Brushing Teeth
Kitten Perpetrated Homicides

27. Correlational Research
Coefficient of Determination: Percentage of variation in one variable that can be predicted based on the other variable.
Square the correlation coefficient by itself
Ex:
.70² = .70 * .70 = .49 = 49%
.24² = .24 * .24 = .057 = 5.7%

28. CORRELATIONAL research
Description: determines the degree to which two variables are related to one another
Advantages
Disadvantages
No manipulation of variables
Allows large populations to be studied at one time
Cost effective and Quick
Enables investigation of difficult variables to study
CANNOT show cause and effect
Does not show the reason for the relationship