1. Chapter 2 PSYCHOLOGICAL RESEARCH
Psychology
Chapter 2 PSYCHOLOGICAL RESEARCH
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2. Claim #1
The Scientific Method
Autism is caused by vaccines.
False

3. The Scientific Method Cont.
Claim #2
The Scientific Method Cont.
Beer before liquor, never been sicker; Liquor before beer, you’re in the clear.
False

4. The Scientific Method Cont.
Claim #3
The Scientific Method Cont.
Students who cram and pull all-nighters often perform better than students who don’t study at all.
False

5. The Scientific Method Cont.
Claim #4
The Scientific Method Cont.
Masturbation can lead to blindness in males.
False

6. The Scientific Method Cont.
A set of steps that are taken in a science to acquire new knowledge.

7. Basic Concepts of Research
Scientific method:
Making observations in a systematic way, following strict rules of evidence and thinking critically about that evidence
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8. Basic Concepts of Research (cont.)
Descriptive studies:
- survey method
- naturalistic
observation
- clinical method
- correlational
method
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9. Basic Concepts of Research (cont.)
Surveys can be administered in a number of ways, including electronically administered research, like the survey shown here. (credit: Robert Nyman)

10. Basic Concepts of Research (cont.)
Jane Goodall made a career of conducting naturalistic observations of
chimpanzee behavior. (credit “Jane Goodall”: modification of work by Erik Hersman; “chimpanzee”: modification of work by “Afrika Force”/Flickr.com)

11. Basic Concepts of Research (cont.)
Descriptive studies (cont.):
- correlation coefficient:
- measures the strength of the correlation
between two quantitative variables
in statistical terms
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12. Basic Concepts of Research (cont.)
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13. Basic Concepts of Research (cont.)
Scatterplots are a graphical view of the strength and direction of correlations. The stronger the correlation, the closer the data points are to a straight line. In these examples, we see that there is (a) a positive correlation between weight and height, (b) a negative correlation between tiredness and hours of sleep, and (c) no correlation between shoe size and hours of sleep.

14. Correlation does not indicate causation
Cause-and-effect relationship - changes in one variable cause the changes in the other variable; can be determined only through an experimental research design.
Confounding variable - unanticipated outside factor that affects both variables of interest, often giving the false impression that changes in one variable causes changes in the other variable..
Example:
As ice-cream sales increase, so does the overall rate in crime.
A relationship exists between ice-cream and crime but is it correlation or does one cause the other?
In this example, temperature is a confounding variable. As the temperature increases, ice-cream sales increase and people are more likely to be outside increasing crime rates.
(Credit: LinkedIn)

15. Longitudinal and Cross-Sectional Research
Cross-Sectional Research – Compares multiple segments of a population at a single time (such as different age groups).
Longitudinal - Studies in which the same group of individuals is surveyed or measured repeatedly over an extended period of time.
Figure 2.11 Longitudinal research like the CPS-3 help us to better understand how smoking is associated with cancer and other diseases. (credit: CDC/Debora Cartagena)

16. Basic Concepts of Research (cont.)
Formal experiments:
- allow researcher to
draw conclusions
about cause-and-
effect relationships
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17. Basic Concepts of Research (cont.)
Theories:
tentative explanations of observations in
science
Hypothesis:
prediction based on a theory
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18. Basic Concepts of Research (cont.)
Empirical evidence:
evidence from observations of publicly
observable behavior
Operational definitions:
describe the observations in terms of the operations of measurement
2008 McGraw-Hill Co., Inc. All rights reserved

19. Basic Concepts of Research (cont.)
Representativeness of samples:
sample:
participants must be representative of
the total group
2008 McGraw-Hill Co., Inc. All rights reserved

20. Basic Concepts of Research (cont.)
What is the theory based on the results of the University of Maine’s therapy dog study?
Article Link: ent.cgi?article=1227&context=honors

21. The Experimental method
Basic Concepts of Research (cont.)
The experimental method is the method in which the research randomly assigns participants to the different conditions in an experiment. It is also the only way to find a cause and effect relationship.

22. The Experimental method cont.
Basic Concepts of Research (cont.)
Involves two key aspects:
Independent Variable—variable that is systematically changed (manipulated) in an experiment.
Dependent Variable—variable that is measured in an experiment.
Random Assignment of Participants to Groups.

23. Basic Concepts of Research (cont.)
Importance of replication in research:
- replication:
- testing a hypothesis in more than one study
- research is more sound if outcome is similar in more than one study
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24. Basic Concepts of Research (cont.)
In an experiment, manipulations of the independent variable are expected to result in changes in the dependent variable. (credit “automatic weapon”: modification of work by Daniel Oines; credit “toy gun”: modification of work by Emran Kassim)

25. Randomly assign into control and experimental groups
Basic Concepts of Research (cont.)
FORMAL EXPERIMENT
Full population of interest
Randomly assign into control and experimental groups
Control group: not exposed to the independent variable: Students who did not play with the therapy dog
Experimental group: exposed to independent variable: Students who played with the therapy dog

26. The experimental method Cont.
Basic Concepts of Research (cont.)
Hypothetical Findings
If the experimental group performs statistically significantly different than the control group, you would have a significant outcome.
What do our findings say about The University of Maine’s study on therapy dogs?

27. The Experimental method Cont.
Basic Concepts of Research (cont.)
Confounding Variables- Undesirable variables that influence the relationship between the IV and DV.

28. Designing an experiment
AVOIDING BIAS AND THE PLACEBO EFFECT
Experimenter bias - researcher expectations skew the results of the study.
Participant bias – participant expectations skew the results of the study.
Single-blind study - experiment in which the researcher knows which participants are in the experimental group and which are in the control group but participants do not. (Controls for participant expectations).
Double-blind Study - experiment in which both the researchers and the participants are blind to group assignments. (Controls for both participant and experimenter expectations).
Placebo effect - people’s expectations or beliefs influencing or determining their experience in a given situation.
Figure 2.16 (credit: Elaine and Arthur Shapiro)

29. Basic Concepts of Research (cont.)
Reliability - consistency and reproducibility of a given result.
A reliable, consistent measurement does not always meant that it is measuring something correctly.
Validity - accuracy of a given result in measuring what it is designed to measure.

30. Ethics: research involving human participants
Research involving human participants must adhere to strict guidelines.
Institutional Review Board (IRB) – Committee of administrators, scientists, and community members that reviews proposals for research involving human participants.
Informed consent - process of informing a research participant about what to expect during an experiment and then obtaining the person’s consent to participate. Includes:
Potential risks involved
Implications of the research
Notification that participation is voluntary
Notification that any data collected will be kept confidential
Figure 2.20 An institution’s IRB meets regularly to review experimental proposals that involve human participants. (credit: modification of work by Lowndes Area Knowledge Exchange (LAKE)/Flickr)

31. Deception
Sometimes deception is necessary to prevent the participant’s knowledge of the research question affecting the results as long as it is not considered harmful.
Deception – Purposely misleading experiment participants in order to maintain the integrity of the experiment.
Debriefing - when an experiment involved deception, participants are told complete and truthful information about the experiment at its conclusion.
Figure 2.21 A participant in the Tuskegee Syphilis Study receives an injection.

32. Basic Concepts of Research (cont.)
Rats, like the one shown here, often serve as the subjects of animal research.