The External Validity of the Sociological Laboratory Experiment

• Applicants: Professor Dr. Roger Berger; Professor Dr. Marc Keuschnigg
• Subject Area: Empirical Social Research
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 278874322

Laboratory experiments are only little established as a canonical method of sociology, which often has been justified by the limited transportability of laboratory findings to the real world. Violations of external validity are particularly serious if generalizations from subject samples not only cover stimulus induced differences between treatment and control groups (e.g. changes in the cooperation rate by 5 percentage points), but absolute values (e.g. a cooperation rate of 50 percent). Effectively, the external validity of sociological experiments has not been tested in a systematic manner. This funding proposal is concerned with the reliability and the external validity of stimulus effects and marginal totals from sociological laboratory experiments. The expected results will allow for a substantiated re-evaluation of previously found laboratory results as well as the identification of relevant parameters to improve the design of future laboratory experimental studies. Employing student subject pools we plan to conduct a series of identical laboratory experiments at two research sites in Leipzig and Munich (parallel test reliability), invite subjects to the laboratory several times in order to study learning and repetition effects (test-retest reliability), vary the effort of the invitation procedure to identify potential effects from self-selection of participants, and vary the anonymity between participants as well as between participants and the experimenter (reactivity). Additionally, we test the validity of online experiments by systematical comparison of laboratory and online results and substantially broaden the subject pool by conducting online experiments with a representative sample of the German population (nationwide transportability) and with international participants to test the cross-cultural generalizability of experimental findings. We will use well-known decision situations from the study of cooperation (dictator game, ultimatum game, prisoners dilemma). The chosen games involve situations of social desirable behavior, vary in complexity, contain stimuli with well assessed effects, and allow for a direct comparison with prior laboratory results. All three situations of interaction are sociologically relevant and offer the possibility to study norms of fairness, sanctions and the threat of sanctions as well as cooperation.

• DFG Programme: Research Grants
• Co-Investigators: Felix Bader; Bastian Baumeister