SOME CAUTIONS ABOUT EXPERIMENTAL RESEARCH A. VALIDITY REFERS TO WHE...

4. Some Cautions About Experimental Research a. Validity refers to whether the experiment studied what it was supposed to study. b. External validity refers to whether the experimental design is representative of real-world issues. c. Internal validity refers to whether changes in the dependent variable are actually due to the manipulation of the independent variable. d. Experimenter Bias i. Experimenter bias occurs when the experimenter’s expectations influence the results of the study. ii. Demand characteristics are any aspect of a study that communicates to participants how the experimenter wants them to behave. e. Research Participant Bias and the Placebo Effect i. Research participant bias occurs when the participant’s behavior during the experiment is influenced by how they believe they are supposed to be behaving. ii. A placebo is an innocuous, inert substance that has no effect on the behavior of the participants. However, the participants are unaware of this; they believe they actually received the manipulation. iii. A placebo effect occurs when the participant’s expectations produce an experimental outcome, even though they did not receive any manipulation. iv. One method to control for both experimenter and participant bias is to conduct a double-blind experiment. In this type of experiment, neither the experimenter nor the participant is aware of which participants are in the experimental group and which are in the control group. D. Applications of the Three Types of Research  All three types of research can be used to address the same topic.  Consider the role of positive experiences in human functioning: Maslow used the descriptive case study approach, McAdams used correlational research, and experimental researchers have randomly assigned individuals to writing tasks about positive experiences as a means of evaluating overall functioning. III. Research Samples and Settings A. The Research Sample