We draw on genetics research to argue that complex psychological phenomena are most likely determined by a multitude of causes and that any individual cause is likely to have only a small effect. Building on this, we highlight the dangers of a publication culture that continues to demand large effects. First, it rewards inflated effects that are unlikely to be real and encourages practices likely to yield such effects. Second, it overlooks the small effects that are most likely to be real, hindering attempts to identify and understand the actual determinants of complex psychological phenomena. We then explain the theoretical and practical relevance of small effects, which can have substantial consequences, especially when considered at scale and over time. Finally, we suggest ways in which scholars can harness these insights to advance research and practices in psychology (i.e., leveraging the power of big data, machine learning, and crowdsourcing science; promoting rigorous preregistration, including prespecifying the smallest effect size of interest; contextualizing effects; changing cultural norms to reward accurate and meaningful effects rather than exaggerated and unreliable effects). Only once small effects are accepted as the norm, rather than the exception, can a reliable and reproducible cumulative psychological science be built.

我们利用遗传学研究来论证复杂的心理现象很可能是由多种原因决定的，并且任何单个原因都可能只有很小的影响。在此基础上，我们强调了持续需要巨大影响的出版文化的危险。首先，它奖励不太可能是真实的夸大效应，并鼓励可能产生这种效应的实践。其次，它忽略了最有可能是真实的微小影响，阻碍了识别和理解复杂心理现象的实际决定因素的尝试。然后，我们解释了微小影响的理论和实践相关性，这可能会产生重大影响，尤其是在大规模和长期考虑时。最后，我们建议学者们利用这些见解来推进心理学研究和实践（即利用大数据、机器学习和众包科学的力量；促进严格的预注册，包括预先指定感兴趣的最小效应大小；情境化效应；改变文化规范以奖励准确和有意义的效果，而不是夸大和不可靠的效果）。只有当小影响被接受为常态而非例外时，才能建立可靠且可重复的累积心理科学。改变文化规范以奖励准确和有意义的效果，而不是夸大和不可靠的效果）。只有当小影响被接受为常态而非例外时，才能建立可靠且可重复的累积心理科学。改变文化规范以奖励准确和有意义的效果，而不是夸大和不可靠的效果）。只有当小影响被接受为常态而非例外时，才能建立可靠且可重复的累积心理科学。