1. Myers’ PSYCHOLOGY Chapter 2 Thinking Critically with Psychological Science James A. McCubbin, PhD Clemson University Worth Publishers

2. The Need for Psychological Science Psychologists, like all scientists, use the scientific method to construct theories that organize observations and imply testable hypotheses

3. The Need for Psychological Science  Hindsight Bias  we tend to believe, after learning an outcome, that we would have foreseen it  the “I-knew-it-all-along” phenomenon  Overconfidence  we tend to think we know more than we do

4. The Need for Psychological Science  Critical Thinking  thinking that does not blindly accept arguments and conclusions  examines assumptions  discerns hidden values  evaluates evidence The Amazing Randi--Skeptic

5. The Need for Psychological Science  Theory  an explanation using an integrated set of principles that organizes and predicts observations  Hypothesis  a testable prediction  often implied by a theory

6. The Need for Psychological Science

7.  Operational Definition  a statement of procedures (operations) used to define research variables  Example-  intelligence may be operationally defined as what an intelligence test measures

8. The Need for Psychological Science  Replication  repeating the essence of a research study to see whether the basic finding generalizes to other participants and circumstances  usually with different participants in different situations

9. Description Psychologists describe behavior using case studies, surveys, and naturalistic observation

10. Description Case Study  Psychologists study one or more individuals in great depth in the hope of revealing things true of us all Is language uniquely human?

11. Description  Survey  technique for ascertaining the self-reported attitudes or behaviors of people  usually by questioning a representative, random sample of people  Random Sample  a sample that fairly represents a population because each member has an equal chance of inclusion

12. Description  False Consensus Effect  tendency to overestimate the extent to which others share our beliefs and behaviors  Population  all the cases in a group, from which samples may be drawn for a study

13. Description

14.  If marbles of two colors are mixed well in the large jar, the fastest way to know their ratio is to blindly transfer a few into a smaller one and count them

15. Description  Naturalistic Observation  observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation

16. Correlation  Correlation Coefficient  a statistical measure of the extent to which two factors vary together, and thus how well either factor predicts the other Correlation coefficient Indicates direction of relationship (positive or negative) Indicates strength of relationship (0.00 to 1.00) r = +.37

17. Correlation  Scatterplot  a graphed cluster of dots, each of which represents the values of two variables  the slope of the points suggests the direction of the relationship  the amount of scatter suggests the strength of the correlation  little scatter indicates high correlation  also called a scattergram or scatter diagram

18. Correlation Perfect positive correlation (+1.00) No relationship (0.00)Perfect negative correlation (-1.00) Scatterplots, showing patterns of correlations

19. Correlation Height and Temperament of 20 Men 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 80 63 61 79 74 69 62 75 77 60 64 76 71 66 73 70 63 71 68 70 75 66 60 90 60 42 60 81 39 48 69 72 57 63 75 30 57 84 39 Subject Height in Inches Temperament Subject Height in Inches Temperament

20. Correlation Scatterplot of Height and Temperament 55 60 65 70 75 80 85 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 Temperament scores Height in inches

21. Correlation Three Possible Cause-Effect Relationships (1) Low self-esteem Depression (2) Depression Low self-esteem Depression (3) Distressing events or biological predisposition could cause or and

22. Illusory Correlation  Illusory Correlation  the perception of a relationship where none exists ConceiveDo not conceive Adopt Do not adopt disconfirming evidence confirming evidence disconfirming evidence confirming evidence

23. Two Random Sequences  Your chances of being dealt either of these hands is precisely the same: 1 in 2,598,960.

24. Experimentation  Experiment  an investigator manipulates one or more factors (independent variables) to observe their effect on some behavior or mental process (the dependent variable)  by random assignment of participants the experiment controls other relevant factors

25. Experimentation  Placebo  an inert substance or condition that may be administered instead of a presumed active agent, such as a drug, to see if it triggers the effects believed to characterize the active agent  Double-blind Procedure  both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo  commonly used in drug-evaluation studies

26. Experimentation  Experimental Condition  the condition of an experiment that exposes participants to the treatment, that is, to one version of the independent variable  Control Condition  the condition of an experiment that contrasts with the experimental treatment  serves as a comparison for evaluating the effect of the treatment

27. Experimentation  Random Assignment  assigning participants to experimental and control conditions by chance  minimizes pre-existing differences between those assigned to the different groups

28. Experimentation  Independent Variable  the experimental factor that is manipulated  the variable whose effect is being studied  Dependent Variable  the experimental factor that may change in response to manipulations of the independent variable  in psychology it is usually a behavior or mental process

29. Experimentation

30. Research Strategies  Design of the subliminal tapes experiment Subliminal tape content Self-esteemMemory Self-esteem Tape label

31. Statistical Reasoning Our Brand Brand Brand Brand X Y Z 100% 99 98 97 96 95 Percentage still functioning after 10 years Brand of truck

32. Statistical Reasoning Our Brand Brand Brand Brand X Y Z 100% 90 80 70 60 50 40 30 20 10 0 Percentage still functioning after 10 years Brand of truck

33. Statistical Reasoning  Mode  the most frequently occurring score in a distribution  Mean  the arithmetic average of a distribution  obtained by adding the scores and then dividing by the number of scores  Median  the middle score in a distribution  half the scores are above it and half are below it

34. Statistical Reasoning A Skewed Distribution 15 20 25 30 35 40 45 50 90 475710 70 Mode Median Mean One Family Income per family in thousands of dollars

35. Statistical Reasoning  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  Statistical Significance  a statistical statement of how likely it is that an obtained result occurred by chance

36. Frequently Asked Questions about Psychology Can laboratory experiments illuminate everyday life?

37. Frequently Asked Questions about Psychology Does behavior depend on ones culture?  Culture--the enduring behaviors, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next

38. Frequently Asked Questions about Psychology Does behavior vary with gender?

39. Frequently Asked Questions about Psychology Why do psychologists study animals? Is it ethical to experiment on animals? Is it ethical to experiment on people?

40. Frequently Asked Questions about Psychology Is psychology free of value judgments?

41. Frequently Asked Questions about Psychology Is psychology potentially dangerous?