Competition and moral behavior: A meta-analysis of forty-five crowd-sourced experimental designs
Authors: Huber Christoph , Dreber Anna , Huber Jürgen , Johannesson Magnus , Kirchler Michael , Weitzel Utz , Abellán Miguel , Adayeva Xeniya , Ay Fehime Ceren , Barron Kai , Berry Zachariah , Bönte Werner , Brütt Katharina , Bulutay Muhammed , Campos-Mercade Pol , Cardella Eric , Claassen Maria Almudena , Cornelissen Gert , Dawson Ian G. J. , Delnoij Joyce , Demiral Elif E. , Dimant Eugen , Doerflinger Johannes Theodor , Dold Malte , Emery Cécile , Fiala Lenka , Fiedler Susann , Freddi Eleonora , Fries Tilman , Gasiorowska Agata , Glogowsky Ulrich , M. Gorny Paul , Gretton Jeremy David , Grohmann Antonia , Hafenbrädl Sebastian , Handgraaf Michel , Hanoch Yaniv , Hart Einav , Hennig Max , Hudja Stanton , Hütter Mandy , Hyndman Kyle , Ioannidis Konstantinos , Isler Ozan , Jeworrek Sabrina , Jolles Daniel , Juanchich Marie , KC Raghabendra Pratap , Khadjavi Menusch , Kugler Tamar , Li Shuwen , Lucas Brian , Mak Vincent , Mechtel Mario , Merkle Christoph , Meyers Ethan Andrew , Mollerstrom Johanna , Nesterov Alexander , Neyse Levent , Nieken Petra , Nussberger Anne-Marie , Palumbo Helena , Peters Kim , Pirrone Angelo , Qin Xiangdong , Rahal Rima Maria , Rau Holger , Rincke Johannes , Ronzani Piero , Roth Yefim , Saral Ali Seyhun , Schmitz Jan , Schneider Florian , Schram Arthur , Schudy Simeon , Schweitzer Maurice E. , Schwieren Christiane , Scopelliti Irene , Sirota Miroslav , Sonnemans Joep , Soraperra Ivan , Spantig Lisa , Steimanis Ivo , Steinmetz Janina , Suetens Sigrid , Theodoropoulou Andriana , Urbig Diemo , Vorlaufer Tobias , Waibel Joschka , Woods Daniel , Yakobi Ofir , Yilmaz Onurcan , Zaleskiewicz Tomasz , Zeisberger Stefan , Holzmeister Felix 
Published: May 2023

Does competition affect moral behavior? This fundamental question has been debated among leading scholars for centuries, and more recently, it has been tested in experimental studies yielding a body of rather inconclusive empirical evidence. A potential source of ambivalent empirical results on the same hypothesis is design heterogeneity—variation in true effect sizes across various reasonable experimental research protocols. To provide further evidence on whether competition affects moral behavior and to examine whether the generalizability of a single experimental study is jeopardized by design heterogeneity, we invited independent research teams to contribute experimental designs to a crowd-sourced project. In a large-scale online data collection, 18,123 experimental participants were randomly allocated to 45 randomly selected experimental designs out of 95 submitted designs. We find a small adverse effect of competition on moral behavior in a meta-analysis of the pooled data. The crowd-sourced design of our study allows for a clean identification and estimation of the variation in effect sizes above and beyond what could be expected due to sampling variance. We find substantial design heterogeneity—estimated to be about 1.6 times as large as the average standard error of effect size estimates of the 45 research designs—indicating that the informativeness and generalizability of results based on a single experimental design are limited. Drawing strong conclusions about the underlying hypotheses in the presence of substantive design heterogeneity requires moving toward much larger data collections on various experimental designs testing the same hypothesis.