Fluency theories predict higher truth judgments for easily processed statements. We investigated two factors relevant for processing fluency: repetition and syntactic complexity. In three online experiments, we manipulated syntactic complexity by creating simple and complex versions of trivia statements. Experiments 1 and 2 replicated the repetition-based truth effect. However, syntactic complexity did not affect truth judgments although complex statements were processed slower than simple statements. This null effect is surprising given that both studies had high statistical power and varied in the relative salience of syntactic complexity. Experiment 3 provides a preregistered test of the discounting explanation by using improved trivia statements of equal length and by manipulating the salience of complexity in a randomized design. As predicted by fluency theories, simple statements were more likely judged as true than complex ones, while this effect was small and not moderated by the salience of complexity.

流畅性理论预测对易于处理的陈述具有更高的真实性判断。我们研究了与处理流畅性相关的两个因素：重复和句法复杂性。在三个在线实验中，我们通过创建简单和复杂版本的琐事陈述来操纵句法复杂性。实验 1 和 2 复制了基于重复的真实效果。然而，尽管复杂语句的处理速度比简单语句慢，但句法复杂性并不影响真值判断。鉴于这两项研究都具有很高的统计功效并且句法复杂性的相对显着性各不相同，这种无效效应令人惊讶。实验 3 通过使用改进的等长琐事陈述并通过操纵随机设计中复杂性的显着性，提供了折扣解释的预注册测试。正如流畅性理论所预测的那样，简单的陈述比复杂的陈述更有可能被判断为真实，而这种影响很小，并且不会因复杂性的显着性而减弱。