Methodology

Our emphasis on experimentation reflects an ongoing movement in the discipline of political science. Appropriate experimental designs offer researchers unparalleled control over stimuli, wide latitude in measurement, and, above all, internal validity: the ability to identify causal relationships between a stimulus and a response. Conducting experiments in a laboratory setting can ensure internal validity, due to the superior control over environmental conditions that laboratories offer, and laboratory settings may be preferred due to the wider range of questions, tests, and tasks that can be administered compared with studies in the field. For example, investigators in our laboratory have collected millisecond response latency data, have administered sophisticated audio-visual treatments, and have even had subjects play the dictator game. Although in the vast majority of our studies, subjects answer questions individually, recently, investigators have conducted multi-agent experiments as well, in which subjects are given the opportunity to consult with each other electronically as part of the study.

Most of the laboratory studies conducted under RIPS rely on convenience samples of undergraduate students at Vanderbilt. The subject pool is typically drawn from both lower-division and upper-division courses in the Department of Political Science (with occasional participation by other departments on campus). Students receive course credit for participating in the studies. Some RIPS studies have also drawn from campus employees and residents of local towns (who are paid for their participation).

Studies under RIPS use a self-administered computer-based survey mode. Occasionally, investigators have supplemented the computer-based mode with other tasks, including dictator games, paper-and-pencil open-ended responses, and behavioral tasks.

We primarily use Qualtrics for general surveys and survey-based experiments. For psychological tests examining cognitive and behavioral processes requiring precise response-time measurements, researchers have used Inquisit, which supports the administration of both close-ended and open-ended questions, as well as the presentation of images and video. Researchers who have fielded multi-agent, interactive studies have utilized Z-Tree.