1. Thinking Critically With Psychological Science Research

2. Everyday Sources of Knowledge Common sense Authority Reasoning Unsystematic observation Scientific method

3. Scientific Method Set of orderly steps used to analyze and solve problems Objectively collected information Empirical evidence – observations of publicly (confirmable) observable behavior Operational definitions – use operations of measurement to describe observations

4. How does research begin?

5. Research Steps Steps – Identify questions of interest – Formulating an explanation Theory: broad explanation Hypothesis: prediction stated in a way that it can be tested – Carrying out research designed to support or refute

6. Who participates in the study? Sample – Representative of larger group or population of interest – Small group of humans or animals – Unrepresentative sample – misleading or biased test of hypothesis Replication of research removes most doubt

7. Sampling

8. How do psychologists observe and describe behavior? Descriptive studies – recording of behaviors that have been recorded systematically – Simplest method of scientific inquiry – Describe behavior and mental processes – Most widely used Survey method – ask people’s opinions Case study – one individual Naturalistic observation – watch, describe Archival research – using already collected data - newspapers Clinical method – observe in clinic setting – All have advantages and disadvantages

9. What type of research study?

10. How do psychologists observe and describe behavior? Correlational Studies – Correlational method: measure two variables for statistical relationship – Variable: anything that can be assigned a numerical value – Uses quantitative measures

11. Correlational Research Correlational Studies – Correlation coefficient Measures each variable Indicates strength ( - 1 to 0 to 1) and direction (negative or positive) of relationship – Correlation does not mean causation – could be a third factor involved Positive correlation – both factors increase – more study, better grades Negative correlation – as one factor increases, the second factor decreases – More study, less recreation No relationship (close to zero) – number of hours studied and height – CORRELATION IS NOT CAUSATION Lack of interest could be affecting test performance not hours studied

12. Correlation coefficients Perfect positive correlation (+1.00) No relationship (0.00)Perfect negative correlation (-1.00)

13. Examples of Correlational Research

14. Example of Cause and Effect Relationships (1) Low self-esteem Depression (2) Depression Low self-esteem Depression (3) Distressing events or biological predisposition could cause or and

15. Experimental Research Tests relationship of two or more variables – Allows conclusions about cause-and-effect – Quantitative measures of behavior compared in different conditions created by researchers – Evidence supports or rejects hypothesis

16. Experimental Design Elements – Independent variable – gets manipulated – Dependent variable – amount of change – Experimental group – exposed to independent variable or conditions expected to create change – Control group – presents normal behavior used for comparison – Random assignment – – – Experimental control

17. Comparing Research Methods Research Method Basic Purpose How Conducted What is Manipulated Descriptive To observe and Case studies, surveys, Nothing record behavior and naturalistic observations Correlational To detect naturally Computing statisticalNothing occuring relationships; association, sometimes to assess how wellamong survey one variable predictsresponses Experimental To explore causeManipulating one orIndependent and effectmore factors and usingvariable(s) random assignment to eliminate preexisting differences among subjects

18. Summary: Types of research

20. Issues that come up in research Internal validity – the extent to which changes in the dependent variable can be attributed to the independent variable Confounding variable – a variable whose unwanted effect on the dependent variable might be confused with that of the independent variable – Subject bias – what the subject expects the study to be about – Experimenter bias – what the researcher expects – Experimenter effects – the personality, dress – Pygmalion effect – the subject performs better because of experimenter Double blind technique

21. Types of Random Assignment Placebo control – Placebo effect: provides no active effect – Use in identical conditions for control and experimental groups Blind experiment – Researchers blind to group membership of participants to rule out experimenter bias Strongest experiments – double blind – Researchers and participants kept blind

22. Descriptive Statistics: summarized data for large groups of participants Central tendency asks what the average score is like in the distribution of scores – Mean: Statistical average of all scores – Median: The fiftieth percentile (half of the scores are above this score, half are below) – Mode: The most frequent score Variability asks how dispersed the scores are relative to the average score or mean – Standard deviation: How far the average participant score deviates from the average (square root of the variance)

23. Bell Curve and Beyond Standard score – (z score) – scores on a normal curve can be described as their distance from the mean of the distribution using SD units – It allows you to compare scores from different distributions Percentile – The score at or below which a particular percentage of scores fall

24. Bell Curve and Skewness Skewness - when scores are bunched up on either side of the bell curve LOOK AT THE TAIL OF THE SKEW – Scores bunched at the high end = negative skew Test is too easy – Scores bunched at the low end = positive skew Test is too hard

25. Inferential Statistics Is the difference between the two groups caused by our manipulation or by chance? We test the null hypothesis – we predict that there will be no effect of the independent variable – No difference btw the groups – fail to reject the null hypothesis – Difference between the two groups – reject the null hypothesis BUT IS THIS BY CHANCE OR FOR REAL?

26. Statistical Significance We are looking for true difference between groups – a statement of probability – the larger the difference between the groups, ______ likely it is by chance. –P–Psychologists accept.05 as being statistically significant A probability of less than 5% that the results occurred by chance The results are more likely to be statistically significant if: –S–Samples are large –T–The differences between the two means is large –T–The variability within the groups is small

27. Inferences Internal validity – the extent to which changes in the dependent variable can be attributed to the independent variable rather than a confounding variable External validity – the extent to which the results of a research study can be generalized Reliable – safe to generalize from a sample – Representative sample – More cases are better than fewer

28. Issues with Experimental Research Complex real-world issues are not easily studied in the laboratory Lab studies may have problems in external validity

29. Evaluating Research

30. APA Ethical Guidelines for Research IRB- Internal Review Board Both for humans and animals.

31. Animal Research Clear purpose Treated in a humane way Acquire animals legally Least amount of suffering possible.

32. Human Research No Coercion- must be voluntary Informed consent Anonymity No significant risk Must debrief

33. Ethics of Research Respecting the rights of human research participants involves: – Informed consent is an explanation of a study and the responsibilities of experimenter and participant – Deception involving the subjects must be justified – Confidentiality of study information must be maintained – Debriefing refers to explaining the research process to the subjects at the end of the study Animal research must be justified and must minimize discomfort to participants

34. Chapter 2 Quiz The Research Enterprise in Psychology

35. Don’t forget to write your answers on a separate piece of paper to grade when you’re done! 1. Organized sets of concepts that explain phenomena are a) independent variables b) dependent variables c) hypotheses d) theories

36. 2. “Students will be able to read a statement printed in the Comic Sans font faster than the same statement written in the Lucida Calligraphy font.” The previous statement is a(n) a) hypothesis b) theory c) replication d) operational definition

37. 3. A theory is a) a tentative statement about the relationship between two or more variables b) a system of interrelated ideas used to explain a set of observations c) a statement of research results that have been proven to be correct d) a preliminary proposal that has yet to be tested

38. 4. Theoretically, random assignment should eliminate a) sampling error b) the need to use statistics c) concerns over validity d) many confounding variables

39. 5. When subjects in the experimental group put a puzzle piece in the wrong place, the experimenter unconsciously winced. The experimenter did not wince when subjects in the control group put a piece in the wrong place. The wincing of the experimenter must be eliminated because it is a) fraudulent b) a demand characteristic c) a confabulation d) a confounding variable

40. 6. The two basic types of statistics are a) descriptive and inferential b) central tendency and variability c) sampling and correlative d) parametric and nonparametric

41. 7. Of the following, which research method is most effective for studying unusually complex or rare phenomena? a) controlled experiment b) surveys c) naturalistic observation d) case study

42. 8. Of the following, which research method would be most appropriate for investigating the relationship between political party membership and attitude toward the death penalty? a) controlled experiment b) naturalistic observation c) test d) survey

43. 9. Of the following, the strongest positive correlation would most likely be shown between a) an adult’s weight and running speed b) close friendships and happiness c) sense of humor and years of education d) visual acuity and salary

44. 10. John wants to study the effects of alcohol on the behavior of college students. For his study, he spends 5 hours every night for 2 weeks at a bar near a college watching how the patrons act before and after drinking alcoholic beverages. The research method John is employing is a a) controlled experiment b) survey c) test d) naturalistic observation

45. 11. What is the median of the following distribution: 6, 2, 9, 4, 7, 3? a) 4 b) 5 c) 5.5 d) 6

46. 12. Of the following, the correlation coefficient that indicates the strongest relationship between the two variables being measured is a) +0.65 b) -0.89 c) 0.00 d) +3.45

47. 13. Inferential statistics help us determine whether ________ played a role in an experiment a) chance b) a dependent variable c) a normal distribution d) genetics

48. 14. Placebo effects occur when a) the sample is not representative of the population b) two variables are confounded c) subjects are influenced by the social desirability bias d) due to their expectations, subjects experience some change from a nonexistent or ineffective treatment

49. 15. Which set of concepts is NOT a closely related set? a) mean, median, mode b) method, results, discussion c) experiment, independent variable, control group d) correlation, sample, journal

50. Chapter 2 Answer Key 1. D 2. A 3. B 4. D 5. D 6. A 7. D 8. D 9. B 10. D 11. B 12. B 13. A 14. D 15. D

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