Endogenous auditory and motor brain rhythms predict individual speech tracking.

In modern digital environments, we are continuously exposed to an overwhelming stream of information that shapes our opinions, attitudes, and behavior. However, not all information encountered is valid, and under conditions of uncertainty, people frequently rely on mental shortcuts to evaluate credibility. Such heuristics often draw on subjective experiences that accompany information processing, such as perceived ease or affective tone. While those heuristics can indeed serve as useful cues when validity is difficult to judge, relying on these internal cues can also lead to systematic biases, or cognitive illusions. One of the most robust examples of such a bias is the illusory truth effect – the tendency for repeated information to be judged as more truthful than novel ones. This effect is largely attributed to processing fluency, the subjective experience of ease when processing repeated (vs. new) information. When information is processed fluently, individuals are more likely to perceive it as correct – a phenomenon that has been shown to arise from manipulations of both perceptual (e.g., Reber and Schwarz,) and conceptual fluency (e.g., Arkes et al.). In line with this, more recently, diffusion-model analyses suggest that the repetition-based truth effect may reflect a combination of perceptual facilitation, a subsequent bias toward affirming repeated statements, and increased speed of information accumulation supporting the truthfulness of the presented information. Research further indicates that this subjective experience of ease is usually accompanied by a positive affective component (see e.g., Topolinski et al., Winkielman), which is also the case in the context of the repetition-based illusory truth effect. Beyond fluency, several studies have shown that positive affective states themselves can evoke a sense of familiarity and induce subjective truth. For instance, Garcia-Marques et al. found that perceived positivity alone can signal familiarity (Experiment 2) and that a positive (vs. neutral) affective state increases the likelihood of judging statements as true (Experiment 3). Similarly, and consistent with the idea that individuals match their current affective states with affectively consistent judgments (see, e.g., the affective matching model,, current research suggests that judging information as true (vs. false) is systematically related to increased positive affect. Recent work has further shown that repetition affects not only judgments of truth but also the subjective confidence with which these judgments are made. This phenomenon is referred to as the illusory certainty effect. The illusory certainty effect describes an increase in individuals’ subjective confidence in their judgments as a function of repetition, independent of whether those judgments are objectively correct. Thus, repeated information is not only more likely to be judged as true, but these judgments are also held with greater subjective certainty. Compared to research on truth judgments, subjective confidence in these judgments has received relatively little attention. The illusory certainty effect represents an initial example of how cognitive shortcuts – such as repetition – not only shape immediate truth judgments but also the confidence with which these judgments are held. It is plausible that this is not an isolated phenomenon restricted to repetition-based effects but rather reflects a more general mechanism that deserves increased attention in future research. At the same time, the cognitive mechanisms underlying the illusory certainty effect remain comparatively underexplored, including whether repetition-based fluency plays a similarly central role in the illusory certainty effect as has been proposed for the illusory truth effect.