Irrelevant information enhances a sense of knowledge and curses our understanding of other minds

This study shows that exposure to topic-related but irrelevant information enhances both estimates of peer knowledge and our own sense of knowledge. In Experiment 1, participants were more confident in their answers to general knowledge questions and gave higher estimates of peer knowledge when such questions were accompanied by short paragraphs containing topic-related yet nondiagnostic information than when they were not. The inflated peer knowledge estimates were independent of the classic curse of knowledge. Experiments 2, 3, 5, and 6 demonstrated that irrelevant information biases knowledge estimation via its semantic relatedness to the test questions; response latencies were measured in Experiments 5 and 6 to examine the possible role of retrieval fluency in the semantic relatedness effect. Experiment 4 attributed the bias to information content (e.g., "it is generally known that keratin is responsible"), not comments on knowledge popularity (e.g., "what is responsible is generally known"). Importantly, the effect of irrelevant information on estimates of peer knowledge was fully mediated by confidence in own knowledge in Experiments 1, 2, 4, and 5. Experiment 6 manipulated retrieval fluency and failed to find conclusive evidence for its involvement in the semantic relatedness effect. We conclude that irrelevant information boosts peer knowledge estimation through its semantic relatedness to the problem at hand, and the effect is mostly explained by a corresponding increase in the individual's own sense of knowledge. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

P300 as a correlate of false beliefs and false statements

INTRODUCTION

This study investigates P300 as a component for false belief and false statement processing with and without a communicative context. The purpose is to understand why P300 has been shown to be commonly involved in false belief and lie processing.

METHODS

Participants were presented with a story in which the protagonist holds a true belief and makes a true statement of it (true belief), holds a false belief and makes a true statement (false belief), or holds a true belief and makes a false statement (false statement) while electroencephalograms were recorded.

RESULTS

In Experiment 1, featuring a solitary protagonist, stronger posterior P300 was shown in the false belief condition than the true belief and false statement condition. With the installation of a communicative context by including a second character listening to the protagonist, Experiment 2 showed enhanced frontal P300 in the false statement condition compared to the true belief and false belief condition. A late slow wave was more prominent in the false belief condition than in the other two conditions in Experiment 2.

CONCLUSION

The present results suggest a situation-dependent nature of P300. The signal captures the discrepancy between belief and reality more readily than that between belief and words under a noncommunicative context. It becomes more sensitive to the discrepancy between belief and words than that between belief and reality in a communicative situation with an audience, which makes any false statement practically a lie.