Unethical behavior is discovered that is more contagious than ethical behavior. This article attempts to propose one of the possible underlying mechanisms-people may have underconfidence bias in information updating due to motivated reasoning, and such bias exhibits in a different direction compared to the overconfident bias documented in the literature on ethical environment, which generate the asymmetric pattern in contagion. This study designs an experiment which relates the unethical behavior to social learning, where a series of subjects with private information about penalty decide sequentially whether to conduct unethical behavior publicly. This study adopts a quantal response equilibrium to construct a structural model for estimation of the bias. In total, 162 university students participated in our experiment and the results confirm the asymmetric patterns that people rely more on others\' precedent decisions rather than their private signal; therefore, the bias facilitates the contagion. This study also tests two punishment systems in the experiment and the results suggest a policy: slightly increasing penalties for the \"followers\" in the early stages would effectively suppress the contagion.

The quality of partners\' relationship can be influenced by the reciprocal respect of the other\'s parenting role, especially when the couple breaks up. This study is aimed at investigating the implicit versus explicit self-serving biases in the evaluation of partners and exes as parents (or potential parents), exploring sex differences and possible relationships with dyadic cohesion. Two Implicit Association Tests and two semantic differentials, comparing each respondent with current partners and last significant exes, and also a scale measuring dyadic cohesion were administered to 108 participants (40 men; M age = 28.1 yr., SD = 8.7). As expected, participants assessed themselves as better than others on both IAT and self-report evaluations, with larger effects toward exes than toward partners and on implicit than explicit measures. Women devalued exes, but not partners, more than men. Dyadic cohesion scores were negatively correlated with the explicit evaluations of partners but not with implicit ones. Theoretical interpretations in terms of self-serving bias were discussed.