确认偏误（或称确认偏差、证实偏差、肯证偏误、验证偏误、验证性偏见）是个人选择性地回忆、搜集有利细节，忽略不利或矛盾的信息，来支持自己已有的想法的片面诠释。

这种偏见尤其显见于感情问题和传统观念。例如，当谈及枪支管制问题时，人们常偏好支持自己原立场的观点，也倾向将模棱两可的事实做有利于自己的解释。偏见的搜索、理解和回忆，常被用来说明态度极化（即使争论双方都依附于相同的根据，争执仍变得极端）、信念固着（在反证出现后依然坚信原有看法）、非理性首因效应（即强烈的「先入为主」效应）及错觉相关（对二件偶然事件做无根据的链接的倾向）等现象。

Confirmation bias, also called confirmatory bias or myside bias, is the tendency to search for, interpret, favor, and recall information in a way that confirms one's preexisting beliefs or hypotheses, while giving disproportionately less consideration to alternative possibilities. It is a type of cognitive bias and a systematic error of inductive reasoning. People display this bias when they gather or remember information selectively, or when they interpret it in a biased way. The effect is stronger for emotionally charged issues and for deeply entrenched beliefs. People also tend to interpret ambiguous evidence as supporting their existing position. Biased search, interpretation and memory have been invoked to explain attitude polarization (when a disagreement becomes more extreme even though the different parties are exposed to the same evidence), belief perseverance (when beliefs persist after the evidence for them is shown to be false), the irrational primacy effect (a greater reliance on information encountered early in a series) and illusory correlation (when people falsely perceive an association between two events or situations).