1. Psychological Science
Chapter Two
Psychological Science

2. RESEARCH GOALS Basic Research Applied Research
Answers fundamental questions about behavior
e.g., how nerves conduct impulses from the skin to the brain
Applied Research
Implications for everyday life; provides solutions to problems
e.g., which type of advertising campaign will reduce alcohol abuse

3. The Scientific Method
= The set of assumptions, rules, and procedures scientists use to conduct research
Empirical *
= Systematic collection & analysis of data
Objective *
= Free from bias

4. Theory Theories can be proven incorrect. This requires *
Most psychologists have a theoretical perspective.
What is a Theory?
an integrated set of principles that explains and predicts many, but not all, observed relationships within a given domain of inquiry.
Theories can be proven incorrect. This requires *
Variables that can be measured
Relationships between variables that can be tested
Prediction of that relationship = a hypothesis

5. Hypothesis Research begins with a hypothesis What is a Hypothesis ?
A specific and falsifiable prediction about the relationship between or among two or more variables.
Variable *
= Any attribute that can have different values.
Give some examples of variables.

6. Descriptive, Correlational, and Experimental Research Designs
Approaches used to collect, analyze and interpret data

7. Which to use?

8. Descriptive Methods Case Study *
Record of one or more individual’s experiences and behavior.
Survey *
Interview or questionnaire measuring beliefs or behaviors in a sample group.*

9. Samples and Populations
the people chosen to participate in a research project
Population *
The people the researcher wants to know about
Representative Sample *
Study participants who closely match the characteristics of the larger population.

10. Observation Naturalistic Observation *
Research based on the observation of everyday events(natural settings)
Video: Observation of Toddler
Laboratory Observation *
Descriptive research conducted by observation of behavior in a controlled setting.

11. Correlation Correlation * A relationship between variables
Correlational Research *
Measures variables and assesses the relationship between them.
Correlation Coefficient *
Indicates the strength and direction of a linear relationship. Correlation coefficient ranges from -1 to +1.

12. Do a Correlational Study
Is there a correlation between hair length and playing violent video games?
Survey students in your class.
How many who consider their hair long play violent video games more than 1 hr. per week?
How many who consider their hair medium?
How many who consider their hair short?
Draw a graph with one axis for hair length, another for # playing violent video games.
Is there a correlation? A cause-effect relationship? If there is a correlation, what might have caused it?

13. Correlation v. Causation
Correlational Research does NOT prove a cause – effect relationship.
positive correlation between the # of violent TV shows children watch and scores on a measure of aggressive play can mean :
1. Violent TV leads to aggressive behavior.
2. Aggressive kids watch more violent TV.
3. Viewing violent TV and aggressive behavior interact.
4. A third variable (e.g., parenting style) leads both to viewing violent TV and behaving aggressively.
How do you prove a cause – effect relationship?
Experimental method *

14. Experimental Method *
A research design in which an independent variable is manipulated to provide evidence for a cause and effect relationship between variables.
Independent variable *
The causing variable, manipulated by the experimenter.

15. Hypothesis states how the independent variable will cause the dependent variable to change.
the measured variable that is expected to be influenced by the experimental manipulation.

16. How do you know the change in the dependent variable was caused by the independent variable?
Compare two groups.
Experimental Group *
Exposed to the experimental manipulation
Control Group *
Not exposed to the experimental manipulation (or exposed to a different level of the manipulation)

17. How do you know the two groups are the same?
Random assignment *
Participants have an equal chance of being in either group. They are assigned to groups randomly.
What if the participants in the experimental group react differently because they received a treatment? (or felt “helped”)
Sometimes a placebo group is also used.

18. A control group which receives an inactive treatment. Placebo effects
changes caused by participant expectations
What if the experimenter is biased?
Double blind technique *
both the researcher and the research participants are blind to condition.

19. Exercise: Applied Research
Watch the video Twitter *
What was the hypothesis?
Was this a descriptive study, a correlational study, or an experiment?
What was the independent variable?
What was the dependent variable?
Which was the experimental group?
Which was the control group?
What were some possible problems with the study?

20. Ethics and Research Costs v. benefits Minimize harm
Participants freely choose to participate
Protect privacy
Informed consent
Minimize deception
Debriefing
Deception and Debriefing ( video)
Institutional review board