Revisiting Gino, Ayal, et al.’s (2009) contagion and differentiation in unethical behavior: A registered conceptual replication and extension

Individual behavior is often shaped by observing others' actions. The seminal Gino, Ayal, et al.'s (2009) study found that individuals behave more dishonestly after witnessing blatant dishonesty by an ingroup member than by an outgroup member. However, because there was no group-irrelevant baseline condition, it remains unclear whether ingroup contagion, outgroup differentiation, or both drive the effect. Furthermore, using natural groups of university students leaves it unclear whether distinct properties of natural groups are necessary, or if mere categorization into arbitrary groups suffices. In this registered report, we tested Gino, Ayal, et al.'s (2009) general hypothesis that exposure to ingroup dishonesty norms increases individual dishonest behavior more than exposure to outgroup dishonesty norms. We conducted a conceptual replication and extension of their Experiment 1 with 3323 U.S. Americans using both minimal and natural groups. Participants were exposed to standardized information about others' dishonest behavior, where we systematically varied the group identities of dishonest others. Then, they completed an incentivized coin-flip task where participants could double their earnings by lying. Despite manipulation checks suggesting that participants processed norm information and strongly identified with natural groups, the pre-registered ingroup-outgroup hypotheses were not supported. Bayesian analyses provided moderate to strong evidence for null effects across comparisons (BF₀₁ = 3.15–14.71). The core ingroup-versus-outgroup prediction received particularly strong null evidence (BF₀₁ > 14). We conclude that exposure to ingroup versus outgroup dishonesty norms, delivered through descriptive statistics in online settings, might not differentially affect individual dishonest behavior, revealing a boundary condition of the original finding.