2. Facts, Theories, and Hypotheses
Objective statement based on observation
Theory
Idea designed to explain facts and make predictions
Hypothesis
Prediction about new facts made from theory
Have you come up with any of your own theories of human behavior?
What hypothesis could you come up with based on this theory?

3. Lessons from Clever Hans
The case of the horse named Clever Hans illustrates a number of issues fundamental to scientific research

4. Lessons from Clever Hans
How does the Clever Hans story illustrate:
the value of skepticism?
the value of controlled experimentation?
the need for researchers to avoid communicating their expectations to subjects?

5. Types of Research Strategies
Strategies vary along three dimensions
Research design
Experiments
Correlational studies
Descriptive studies
Setting
Field
Laboratory
Data collection method
Self-report
Observation

6. Research Design: Experiments
Studies cause-effect relationships
Aim is to study how the dependent variable depends on the independent variable
Independent Variable
Variable that is hypothesized to cause some effect on another variable
Dependent Variable
Variable that is hypothesized to be affected
Have you ever done a science project or been a subject in a study?
What was it like?

7. Research Design: Within Subjects Experiment
Same individual/group in two conditions
Clever Hans
Independent variables
Dependent variables
It is helpful to ask students what independent and dependent variables are, before explaining them.

8. Research Design: Between Subjects Experiment
Different individual/group in different conditions
DiMascio’s depression study
Independent variables
Dependent variables
Random assignment

9. Research Design: Between Subjects Experiment
FIGURE 2.1 Effect of treatment condition on depression Subjects who received both drugs and psychotherapy were the least depressed at the end of the 16-week treatment period (according to the results of a standard interview procedure scored on a 17-point scale). In contrast, subjects who received no treatment were the most depressed. (Based on data from DiMascio et al., 1979.)

10. Research Design: Correlational Studies
Observes/measures the relationship between two variables
Does NOT show cause and effect
Example: Diana Baumrind’s study on parental discipline and child behavior

11. Research Design
What are the differences in procedure between a correlational study and an experiment?
How do the types of conclusions that can be drawn differ between a correlational study and an experiment?

12. Research Design: Descriptive Studies
Describes the behavior of individuals without assessing relationships
Example: Jane Goodall’s study on African chimpanzees
Next time you are in a coffee shop or cafeteria, take a few minutes to observe a person or group of people. What do you notice?

13. Research Settings Advantages and disadvantages Laboratory studies
Any research study in which the subjects are brought to a specially designated area that has been set up to facilitate the researcher’s collection of data or control over environmental conditions
Field studies
Any research study conducted in a setting in which the researcher does not have control over the experiences that a subject has
Would a study that videotapes a family at dinner be a laboratory study or field study?
Would it be okay to videotape the family without them knowing?
Advantages and disadvantages
Laboratory studies
Field studies

14. Data Collection Methods
Self-report
Questionnaire
Interview
Introspection
Observation
Naturalistic observation
Tests

15. Statistical Methods in Psychology
Tells us that the results are not due to chance
Descriptive statistics
Inferential statistics

16. Descriptive Statistics
Measures of central tendency
Mean
Median
Mode
Measures of variability
Range
Standard deviation

17. The Same Mean, But Different Variability
In set A, the scores cluster close to the mean (low variability); in set B, they differ widely from the mean (high variability). A common measure of variability is the standard deviation, which is calculated by a formula described in the Statistical Appendix. As we see here, the further most individual scores are from the mean, the greater is the standard deviation.

18. Describing a Correlation
Correlation coefficients range from to +1.00
Positive correlation
Negative correlation
Strength of correlation
Scatterplot
If desired, add another slide after this one with examples of scatterplots.

19. Examples of Correlations
Examples of correlations, using made-up data The table above shows the most recent test score and four other measures for each of 10 students in a college course. At the bottom of each of the four right-hand columns is the correlation coefficient relating the data of that column to the test score. (The study is fictitious and the data were made up for illustrative purposes.) The four scatter plots depict, separately, the correlation between the test score and each of the four other measures. By comparing the plots, you can see the difference between weaker and stronger correlations and between positive and negative correlations.

20. Inferential Statistics
Tells us how likely it is that results are due to chance alone
Statistical significance
p >.05
What affects significance?
Size of effect
Number of observations
Variability of the data

21. Minimizing Bias in Psychology
Error
Random variability in results
Bias
Nonrandom variability in results
Three types of bias
Sampling biases
Measurement biases
Expectancy biases

22. Examples of Variation and Bias
FIGURE 2.4 Random variation, bias, and both The difference between random variation in behavior and bias in research is like the difference between the sets of target holes produced by a novice archer (target A) and by a skilled archer whose bow sights are misaligned (target B). Target C shows the results from a novice archer using misaligned bow sights.

23. Avoiding Measurement Biases
Reliability
Yields similar results each time it is used
Validity
Measures or predicts what it is said to measure or predict
Face validity
Criterion validity

24. Avoiding Observer-Expectancy and Subject-Expectancy Effects
Blind experiment
Observer is ‘blind’
Double-blind experiment
Observer and subject are ‘blind’
May use a placebo

25. Ethical Issues in Psychological Research
Human Subjects
A human subject’s right to privacy must be protected
The risk of discomfort or harm to human subjects must be minimal
Deceiving subjects about some aspect of a study is both common and controversial
Routine measures to protect subjects include obtaining informed consent, letting subjects know they can quit at any time, ensuring anonymity in results, and debriefing subjects about deception after the study ends.

26. Ethical Issues in Psychological Research
Animal Subjects
Many procedures that would be unethical with humans—such as controlled breeding and surgical interventions—are performed with animals
The benefits of the knowledge gained from such research are the primary ethical justification for them, since common biological mechanisms often enable us to apply findings from animal studies to humans
Animals used in research must be well cared for, must not suffer unnecessary deprivation or pain, and must have their suffering balanced against the potential value of the knowledge gained.

27. Assessment
Come up with an idea for your own experiment and identify the independent and dependent variables.
Students can write down their answers to hand in, either with or without their names. Or, if there is time, they can discuss their answers aloud.
If this chapter takes two or more days, you may want to add in your own Quick Questions and Assessments where you left off and started again.