1. Thinking Critically With Psychological Science Chapter 1: Experimental Method and Descriptive Research

2. The Need for Psychological Science?  Did We Know It All Along? Hindsight Bias  Overconfidence  The Scientific Attitude  Critical Thinking

3. Why “Do” Psychology? 1.How can we differentiate between uniformed opinions and examined conclusions? 2.The science of psychology helps make these examined conclusions, which leads to our understanding of how people feel, think, and act as they do!

4. What About Intuition & Common Sense? Many people believe that intuition and common sense are enough to bring forth answers regarding human nature. Intuition and common sense may aid queries, but they are not free of error.

5. Limits of Intuition Personal interviewers may rely too much on their “gut feelings” when meeting with job applicants. Taxi/ Getty Images

6. Hindsight Bias is the “I-knew-it-all-along” phenomenon. After learning the outcome of an event, many people believe they could have predicted that very outcome. Example: We only knew the dot.com stocks would plummet after they actually did. Hindsight Bias

7. Overconfidence Sometimes we think we know more than we actually know. The tendency to assume that we will know or perform better than we probably will. Anagram BARGEGRABE ENTRYETYRN WATERWREAT How long do you think it would take to unscramble these anagrams? People said it would take about 10 seconds, yet on average they took about 3 minutes (Goranson, 1978).

8. Hindsight Bias and Overconfidence together… Often lead us to overestimate our intuition. However, scientific inquiry can help us sift reality from illusion….

9. The Scientific Attitude The scientific attitude is composed of curiosity (passion for exploration), skepticism (doubting and questioning) and humility (ability to accept responsibility when wrong).

10. Critical Thinking Critical thinking does not accept arguments and conclusions blindly. It examines assumptions, discerns hidden values, evaluates evidence and assesses conclusions.

11. How Do Psychologists Ask & Answer Questions? Psychologists, like all scientists, use the scientific method to construct theories that organize, summarize and simplify observations.

12. A theory is an explanation that integrates principles and organizes and predicts behavior or events. For example, low self-esteem contributes to depression. Theory

13. The Experimental Method An experiment is a carefully controlled method of investigation used to establish a cause-and-effect relationship. The experimenter purposely manipulates and controls selected variables in order to determine cause and effect.

14. A hypothesis is a testable prediction, often prompted by a theory, to enable us to accept, reject or revise the theory. –A hypothesis is TENTATIVE. It describes the relationship between 2 or more variables. –A hypotheses MUST be testable, verifiable, and refutable. People with low self-esteem are apt to feel more depressed. Hypothesis

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

16. An independent variable is a factor manipulated or controlled by the experimenter. The effect of the independent variable is the focus of the study. For example, when examining the effects of breast feeding upon intelligence, breast feeding is the independent variable. Independent Variable

17. A dependent variable is a factor that may change in response to an independent variable. In psychology, it is usually a behavior or a mental process. –The dependent variable is the factor that is MEASURED by the experimenter. It is affected and thus dependent on the independent variable. For example, in our study on the effect of breast feeding upon intelligence, intelligence is the dependent variable. Dependent Variable

18. Example… An experimenter wants to determine if playing violent video games increases the frequency of aggressive behavior in children. –The INDEPENDENT variable in this study is the type of video game played. –The DEPENDENT variable in this study is the amount of aggressive behavior exhibited by the children.

19. Another Example An experimenter wants to determine if a new drug reduces hyperactivity in children. –The independent variable in this study is the drug. –The dependent variable in this study is level of hyperactivity.

20. And Yet….Another Example… An experimenter wants to determine the relationship between rehearsal/repetition of a list of definitions of the difficult SAT vocabulary words and later recall of these definition. The independent variable is the amount of rehearsal/repetition. The dependent variable is the recall of correct definitions.

21. Now…one step further… Using the SAT Example… –You then need to be very specific with how you plan to manipulate and MEASURE the variable. Rehearsal might be the number of times the subject reads aloud a list of words. Difficult words might be defined as answers to Level 5 SAT sentence completion questions. Recall might be defined as the percentage of words that are correctly defined.

22. Experimental and Control Groups The EXPERIMENTAL group is the group that is exposed to the independent variable. The CONTROL group is the group that is exposed to all experimental conditions EXCEPT the independent variable. This allows for comparisons…..

23. Experimental Controls Used to ensure that all groups in the experiment are treated exactly the same, except for the independent variable.

24. OUT OF OUR CONTROL... Nothing is perfect….there are EXTRANEOUS or CONFOUNDING variables to worry about… –Differences between the experimental and control group other than the independent variable…they can have an unwanted influence on the outcome of an experiment. Example: in the study measuring the impact of playing violent video games on the frequency of aggression in children, extraneous variables could include the income level of the children’s parents and the incidence of child abuse.

25. COMMON PROBLEMS BIAS…occurs when a researcher’s expectations or preferences about the outcome of a study influence the results in a hoped-for direction. –SAMPLE BIAS occurs when research participants are not representative of the larger population.

26. Sample Bias by the Researcher Selection Bias: Researcher selects sample in a way that makes it unrepresentative of the population. –Example: Republican presidential poll interviewing a random sample of residents of Kansas. –Example: Democratic presidential poll interviewing a random sample of residents of Maryland.

27. Con’t. Participation Bias: Arises in surveys and polls whenever people can CHOOSE to participate. Usually people who feel more strongly about an issue are more likely to participate. –Example: A TV show asking viewers to respond to a question by paying $1.00 to call a 900 telephone number.

28. Procedure by which participants are assigned to experimental and control groups by chance. This minimizes pre-existing differences between those assigned to the different groups. Solutions… Random Assignment

29. Another …. Incorporate a PLACEBO… –An inactive substance or fake treatment often used as a control technique in drug research.

30. And Another… SINGLE-BLIND STUDY…. –A procedure in which the subjects do not know whether they are in the experiment or the control group.

31. And Another DOUBLE-BLIND STUDY… –Procedure in which neither the researcher nor the participant knows which group received the experimental treatment.

32. Research Process

33. Descriptive Research Uses observation without manipulating variables. DOES NOT enable researchers to establish cause and effect relationships. Includes surveys, naturalistic observation, case studies, and studies of development.

34. Case Study A technique in which one person is studied in depth to reveal underlying behavioral principles. Enables researchers to obtain detailed knowledge about a person. Provide opportunities to conduct in-depth studies or rare and unusual cases. Cannot be used to establish cause and effect relationships. Susceptible to inaccurate reporting and the subject’s biased views.

35. Survey A technique for ascertaining the self-reported attitudes, opinions or behaviors of people usually done by questioning a representative, random sample of people. –The entire group to be studied is called a POPULATION. –Researchers generally question only a sample of the population whose opinions they seek to assess. –A RANDOM sample, in which every person in the population has an equal chance of participating, helps minimize bias and ensure that the sample is representative.

36. Survey Random Sampling If each member of a population has an equal chance of inclusion into a sample, it is called a random sample (unbiased). If the survey sample is biased, its results are not valid. The fastest way to know about the marble color ratio is to blindly transfer a few into a smaller jar and count them.

37. SOCIAL DESIRABILITY BIAS Survey respondents often report that they are healthier, happier, and less prejudiced than would be expected based upon the results of other types of research. This is called SOCIAL DESIRABILITY BIAS.

38. Survey Wording can change the results of a survey. –Example: Study for Newsweek showing the effect of wording on the outcome of a survey (1998). Do you personally believe that abortion is wrong (57% yes) Whatever your own personal view on abortion, do you favor or oppose a woman in this country having the choice to have an abortion with the advice of her doctor? (69% yes) Wording Effects

39. Naturalistic Observation Observing and recording the behavior of subject in their natural setting and recording self-seating patterns in a multiracial school lunch room constitute naturalistic observation. Researchers only observe, do not get involved, or interact with subjects. This type of research provides a “slice of life” that can be revealing, but it is important to remember that they are DESCRIPTIVE and do not EXPLAIN behavior.

40. Developmental Studies Longitudinal method measures a single individual or group of individuals over an extended period of time. –Example: A longitudinal study of intelligence would retest the same people over a period of years. Provides in-depth information but can be expensive and time-consuming.

41. Another… Cross-sectional method compares individuals of various ages at one point in time. –Example: A cross-sectional study of achievement motivation would test 8 th, 10 th, and 12 th grade students at the beginning of the school year. Provides information about age differences, but difficult to make generalizations since only measures behavior at one point in time.

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