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Researchers can test cause-and-effect hypotheses by conducting experiments. Ideally, experimental participants are randomly selected from the population of interest. Then, the participants are randomly assigned to their respective groups. Sometimes, the researcher and the participants are blind to group membership to prevent their expectations from influencing the results.

In ideal experimental design, the only difference between the experimental and control groups is whether participants are exposed to the experimental manipulation. Each group goes through all phases of the experiment, but each group will experience a different level of the independent variable: the experimental group is exposed to the experimental manipulation, and the control group is not exposed to the experimental manipulation. The researcher then measures the changes that are produced in the dependent variable in each group. Once data is collected from both groups, it is analyzed statistically to determine if there are meaningful differences between the groups.

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Psychologists report their research findings in peer-reviewed journal articles. Research published in this format is checked by several other psychologists who serve as a filter separating ideas that are supported by evidence from ideas that are not. Replication has an important role in ensuring the legitimacy of published research. In the long run, only those findings that are capable of being replicated consistently will achieve consensus in the scientific community.

2.4 Ethics Ethics in research is an evolving field, and some practices that were accepted or tolerated in the past would be considered unethical today. Researchers are expected to adhere to basic ethical guidelines when conducting experiments that involve human participants. Any experiment involving human participants must be approved by an IRB. Participation in experiments is voluntary and requires informed consent of the participants. If any deception is involved in the experiment, each participant must be fully debriefed upon the conclusion of the study.

Animal research is also held to a high ethical standard. Researchers who use animals as experimental subjects must design their projects so that pain and distress are minimized. Animal research requires the approval of an IACUC, and all animal facilities are subject to regular inspections to ensure that animals are being treated humanely.

Review Questions

1. Scientific hypotheses are ________ and falsifiable.

a. observable b. original c. provable d. testable

2. ________ are defined as observable realities. a. behaviors b. facts c. opinions d. theories

3. Scientific knowledge is ________. a. intuitive b. empirical c. permanent d. subjective

4. A major criticism of Freud’s early theories involves the fact that his theories ________.

a. were too limited in scope b. were too outrageous c. were too broad d. were not testable

5. Sigmund Freud developed his theory of human personality by conducting in-depth interviews over an extended period of time with a few clients. This type of research approach is known as a(n): ________.

a. archival research b. case study c. naturalistic observation d. survey

70 Chapter 2 | Psychological Research

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6. ________ involves observing behavior in individuals in their natural environments.

a. archival research b. case study c. naturalistic observation d. survey

7. The major limitation of case studies is ________.

a. the superficial nature of the information collected in this approach

b. the lack of control that the researcher has in this approach

c. the inability to generalize the findings from this approach to the larger population

d. the absence of inter-rater reliability

8. The benefit of naturalistic observation studies is ________.

a. the honesty of the data that is collected in a realistic setting

b. how quick and easy these studies are to perform

c. the researcher’s capacity to make sure that data is collected as efficiently as possible

d. the ability to determine cause and effect in this particular approach

9. Using existing records to try to answer a research question is known as ________.

a. naturalistic observation b. survey research c. longitudinal research d. archival research

10. ________ involves following a group of research participants for an extended period of time.

a. archival research b. longitudinal research c. naturalistic observation d. cross-sectional research

11. A(n) ________ is a list of questions developed by a researcher that can be administered in paper form.

a. archive b. case Study c. naturalistic observation d. survey

12. Longitudinal research is complicated by high rates of ________.

a. deception b. observation c. attrition d. generalization

13. Height and weight are positively correlated. This means that:

a. There is no relationship between height and weight.

b. Usually, the taller someone is, the thinner they are.

c. Usually, the shorter someone is, the heavier they are.

d. As height increases, typically weight increases.

14. Which of the following correlation coefficients indicates the strongest relationship between two variables?

a. –.90 b. –.50 c. +.80 d. +.25

15. Which statement best illustrates a negative correlation between the number of hours spent watching TV the week before an exam and the grade on that exam?

a. Watching too much television leads to poor exam performance.

b. Smart students watch less television. c. Viewing television interferes with a

student’s ability to prepare for the upcoming exam.

d. Students who watch more television perform more poorly on their exams.

16. The correlation coefficient indicates the weakest relationship when ________.

a. it is closest to 0 b. it is closest to -1 c. it is positive d. it is negative

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17. ________ means that everyone in the population has the same likelihood of being asked to participate in the study.

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