Personality, 9e Jerry M. Burger © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Personality Research Methods Chapter 2 © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Chapter Outlines Hypothesis-testing approach Case study method Statistical analysis of data Personality assessment © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 3

Hypothesis-Testing Approach Theory: General statement about the relationship between constructs or events Differ in the range of events or phenomena they explain Characteristics of a good theory Parsimonious - Explains the phenomenon in simple terms Useful - Generates testable hypothesis © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 4

Hypothesis-Testing Approach Hypothesis: Formal prediction about the relationship between two or more variables that is logically derived from the theory A theory is unaccepted if empirical investigations consistently fail to confirm predictions © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 5

Figure 2.1 - Example of the Hypothesis-Testing Approach © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 6

Types of Experimental Variables Independent: Determines how the groups in the experiment are divided Is manipulated by the experimenter Known as treatment variable Dependent: Measured by the investigator and used to compare the experimental groups Known as outcome variable © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 7

Interaction of Experimental Variables How one independent variable affects the dependent variable depends on the other independent variable © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 8

Manipulated Versus Nonmanipulated Independent Variables Begins with a large number of participants Randomly assigns participants to experimental groups Researchers assume that all the differences will be evened out Exists without the researcher’s intervention Investigator does not randomly assign participants to a condition Researcher cannot assume the people in the two groups are identical Difficult to find cause-and-effect relationships © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 9

Prediction Versus Hindsight Accurate predictions can be made if a scientist has a legitimate theory Purpose of research is to provide support for a hypothesis © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 10

Prediction Versus Hindsight Researchers: Generate a theory Make a hypothesis Collect data that supports or opposes hypothesis Unpredicted findings by the researchers are the basis for future hypotheses and research © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 11

Replication Examines participant populations different from those used in the original research Helps to determine whether the effect applies to larger number of people or is limited to the kind of individuals used in the original sample © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 12

Replication Determining the strength of an effect by how often it is replicated is difficult File Drawer problem Investigators publish and report research only when they find significant effects Failed attempt at replication makes researcher to decide something has gone wrong Leads research being stored in a file drawer and never reported © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 13

Case Study Method In-depth evaluation of individuals Participant is a psychotherapy client suffering from a problem that interests the investigator Researcher records in detail: Person’s history Current behavior Changes in behavior © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 14

Case Study Data are usually descriptive Psychologists rely on in-depth analysis of the patients while formulating ideas about personality Helped behaviorists to illustrate: Various aspects of their theories Effectiveness of their therapies © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 15

Limitations of Case Study Method Generalizing from a single individual to other people Determining cause-and-effect relationships with the case study method Interference of investigator's subjective judgments with scientific objectivity © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 16

Strengths of the Case Study Method Offers insight into the richness of a person's life Valuable for generating hypotheses about the nature of human personality Acts as a useful research tool Appropriate in examining a rare case © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 17

Strengths of the Case Study Method Suitable for arguing that the individual being studied is normal on the dimensions of interest Illustrates a treatment Demonstrates possibilities © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 18

Statistical Analysis of Data Types of statistical tests appropriate for different types of data and research designs Analysis of variance Chi-square test Correlation coefficient © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 19

Statistical Analysis of Data Statistical significance The difference between two averages is large enough to consider that it was not caused by chance but reflects a true difference between two observations Size of the difference is indicated through statistical values known as effect size indicators © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 20

Statistical Analysis of Data Correlation coefficients Statistical test that helps understand the relationship between two measures Statistical data is reduced to a single number that ranges from 1.00 to -1.00 © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 21

Figure 2.3 - Three Possible Relations Between Loneliness and Depression © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 22

Reliability Extent to which a test measures consistently Determined by calculating test-retest reliability coefficient Factors contributing to poor consistency Vague test questions or scoring procedures Fluctuation in response due to taker’s mood Internal consistency All items on the test measure the same thing © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 23

Reliability Internal consistency coefficient High coefficient indicates that most of the items are measuring the same concept Low coefficient suggests items are measuring more than one concept © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 24

Validity Extent to which a test measures what it is designed to measure Easy to determine for some kinds of tests Face validity Way to decide whether a test measures what it says it measures is to look at the test items Less certain than with more straightforward measures © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 25

Validity Congruent validity Discriminant validity Extent to which scores from the test correlate with other measures of the same construct Otherwise known as convergent validity Discriminant validity Extent to which a test score does not correlate with the scores of theoretically unrelated measures © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 26

Validity Behavioral validation Step in determining the construct validity of a test Test scores predicting relevant behavior is important Usefulness of the test must be questioned if test scores cannot predict behavior © 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2 - 27