Validation of text information as a general mechanism for detecting inconsistent or false information is an integral part of text comprehension. This study examined how the credibility of the information source affects validation processes. Two experiments investigated combined effects of source credibility and plausibility of information during validation with explicit (ratings) and implicit (reading times) measurements. Participants read short stories with a high-credible versus low-credible person that stated a consistent or inconsistent assertion with general world knowledge. Ratings of plausibility and ratings of source credibility were lower when a credible source stated a world-knowledge inconsistent assertion compared with a low-credible source. Reading times on target sentences and on spillover sentences were slower when a credible source stated an assertion inconsistent with world knowledge compared with a low-credible source, suggesting that source information modulated the validation of implausible information. These results show that source credibility modulates validation and suggest a bidirectional relationship of perceived plausibility and source credibility in the reading process.

This study examined the role of source credibility in the validation of factual information embedded in short narratives. In a self-paced reading experiment, we tested the assumption that the degree of (im-)plausibility determines the extent that source credibility affects validation during comprehension. We used reading times of target and spillover sentences and plausibility judgments as indicators of validation. Participants read stories with a high-vs. low-credible person (expert vs. non-expert) who made plausible, somewhat implausible, or highly implausible assertions. Reading times increased and plausibility judgments varied as a function of knowledge consistency, decreasing from knowledge-consistent to implausible to knowledgeinconsistent items. Moreover, interactions of source credibility and plausibility were found for reading times of spillover sentences and plausibility judgements, indicating that source credibility and plausibility are jointly considered in validation. High-credible sources mitigated the perceived implausibility of somewhat implausible sentences but exacerbated the perceived implausibility of highly implausible information. A corresponding interactive pattern was found for the reading times of the spillover sentences. Thus, implicit and explicit indicators provided converging evidence that the modulating role of source credibility in validation depends on the degree of implausibility.

The general knowledge questions introduced by Nelson and Narens (Journal of Verbal Learning and Verbal Behavior, 19(3), 338–368, 1980) have been a valuable research tool in various areas of cognitive research. We translated, updated, and expanded the set of questions for German. We present a total set of 356 general knowledge questions with their recall probability as well as metacognitive measures—confidence and peer judgments—based on a university student sample (N = 512). Furthermore, we present response latencies, pairwise correlations between recall probability and metacognitive judgments as well as the most common commission errors. These general knowledge questions can be used in studies with German speaking participants in a broad range of research fields, such as memory, illusory truth, misinformation, and metacognitive processes.

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