1 PSYCHOLOGY (8th Edition, in Modules) David Myers PowerPoint Slides Aneeq Ahmad Henderson State University Worth Publishers, © 2007

2 Research Strategies: How Psychologists Ask and Answer Questions Module 3

3 Research Strategies: How Psychologists Ask and Answer Questions Description  The Case Study  The Survey  Naturalistic Observation Correlation  Correlation and Causation  Illusory Correlation  Perceiving Order in Random Events

4 Research Strategies: How Psychologists Ask and Answer Questions Experimentation  Exploring Cause and Effect  Evaluating Therapies  Independent and Dependent Variables Statistical Reasoning  Describing Data  Making Inferences

5 Description Case Study A technique in which one person is studied in depth to reveal underlying behavioral principles. Is language uniquely human? Susan Kuklin/ Photo Researchers

6 Case Study A clinical study is a form of case study where the therapist investigates the problems associated with a client. Clinical Study

7 Survey A technique for ascertaining the self-reported attitudes, opinions or behaviors of people usually by questioning a representative, random sample of people.

8 Survey Wording can change the results of a survey. Q: Should cigarette ads and pornography be allowed on television? (not allowed vs. forbid) Wording Effect

9 Survey A tendency to overestimate the extent to which others share our beliefs and behaviors. False Consensus Effect

10 Survey Random Sampling From a population, if each member has an equal chance of inclusion into a sample, we call that a random sample (unbiased). If the survey sample is biased, its results are spurious. The fastest way to know about the marble color ratio is to blindly transfer a few into a smaller jar and count them.

11 Naturalistic Observation Observing and recording behavior of animals in the wild, to recording self-seating patterns in lunch rooms in a multiracial school constitute naturalistic observation. Courtesy of Gilda Morelli

12 Descriptive Methods Case studies, surveys, and naturalistic observation all describe behaviors. Summary

13 Correlation When one trait or behavior accompanies another, we say the two correlate. Correlation coefficient Indicates direction of relationship (positive or negative) Indicates strength of relationship (0.00 to 1.00) r = Correlation Coefficient is a statistical measure of relationship between two variables.

14 Perfect positive correlation (+1.00) Scatterplot is a graph comprised of points generated by values of two variables. The slope of points depicts the direction, and the amount of scatter the strength of relationship. Scatterplots

15 No relationship (0.00) Perfect negative correlation (-1.00) Scatterplot on the left shows a negative correlation, and the one on the right shows no relationship between the two variables. Scatterplots

16 Data Data showing height and temperament in people.

17 Scatterplot Scatterplot showing relationship between height and temperament in people with a moderate positive correlation of

18 or Correlation and Causation

19 Illusory Correlation The perception of a relationship where none exists. Parents conceive children after adoption. Confirming evidence Disconfirming evidence Do not adopt Disconfirming evidence Confirming evidence Adopt Do not conceive Conceive Michael Newman Jr./ Photo Edit

20 Given random data we look for order, for meaningful patterns. Order in Random Events Your chances of being dealt either of these hands is precisely the same: 1 in 2,598,960.

21 Order in Random Events Given large number of random outcomes, a few are likely to express order. Angelo and Maria Gallina won two California lottery games on the same day. Jerry Telfer/ San Francisco Chronicle

22 Experimentation Like other sciences, experimentation forms the backbone of research in psychology. Experiments isolate causes and their effects. Exploring Cause and Effect

23 Many factors influence our behavior. Experiments (1) manipulate factors that interest us while keeping other factors under (2) control. Effects generated by manipulated factors isolate cause and effect relationships. Exploring Cause & Effect

24 Independent Variable is a factor, manipulated by the experimenter, and whose effect is being studied. For example, to study the effect of breast feeding on intelligence. Breast feeding is the independent variable. Independent Variable

25 Dependent Variable is a factor that may change in response to independent variable. In psychology it is usually a behavior or a mental process. For example, in our study on the effect of breast feeding on intelligence. Intelligence is the dependent variable. Dependent Variable

26 In evaluating drug therapies it is important to keep the patients and experimenter’s assistants blind to which patients got real treatment and which placebo. Evaluating Therapies Double-blind Procedure

27 Assigning participants to experimental (Breast- fed) and control (formula-fed) conditions by random assignment minimizes pre-existing differences between the two groups. Evaluating Therapies Random Assignment

28 Experimentation A summary of steps during experimentation.

29 Comparison Below is a comparison of different research methods.

30 Statistical Reasoning Statistical procedures analyze and interpret data and let us see what the unaided eye misses. Composition of ethnicity in urban locales

31 Describing Data Meaningful description of data is important in research. Misrepresentation can lead to incorrect conclusions.

32 Measures of Central Tendency Mode: The most frequently occurring score in a distribution. Mean: The arithmetic average of scores in a distribution obtained by adding the scores and then dividing by their number. Median: The middle score in a rank-ordered distribution.

33 Measures of Central Tendency A Skewed Distribution

34 Measures of Variation Range: The difference between the highest and lowest scores in a distribution. Standard Deviation: A computed measure of how much scores vary around the mean.

35 Standard Deviation

36 Making Inferences A statistical statement of how likely an obtained result occurred by experimental manipulation or by chance.

37 Making Inferences 1.Representative samples are better than biased samples. 2.Less variable observations are more reliable than more variable ones. 3.More cases are better than fewer cases. When is an Observed Difference Reliable?

38 Making Inferences When sample averages are reliable and the difference between them is relatively large, we say the difference has statistical significance. For psychologists this difference is measured through alpha level set at 5 percent. When is a Difference Significant?