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The Credibility Loop: Meta-Analysis of Two Experiments Studying Credibility Evaluations using EEG
Andrzej Kawiak, Łukasz Kwaśniewicz, Piotr Schneider, Adam Wierzbicki, Grzegorz Wójcik
Presenting author:
Adam Wierzbicki
Understanding how humans evaluate credibility is an important scientific question in the era of fake news. Source credibility is among the most important aspects of credibility evaluations. One of the most direct ways to understand source credibility is to use measurements of brain activity of humans who make credibility evaluations. We report the results of two EEG experiments which measured brain activity during credibility evaluation.

In the experiments, participants had to evaluate quiz responses of fictitious students based on the students’ source credibility. In the first experiment, source credibility was given. In the second experiment, participants had to learn source credibility based on a preparatory stage, during which they evaluated message credibility with perfect knowledge.

The experiments allowed for identification of brain areas that were active when a participant made positive or negative credibility evaluations. Based on data from the two experiments, we modeled and predicted human source credibility evaluations using EEG brain activity measurements with F1 score exceeding 0.7 (using 10-fold cross-validation). Models of source credibility differed significantly from models of message credibility evaluations with perfect knowledge.

We compare results from the two experiments and find an overlap between the Brodman areas whose activity was used as an explanatory variable for predicting source credibility evaluations. In particular, L-BA11, R-BA23, L-BA24, R-BA42 and L-BA47 occur as the most significant explanatory variables in both experiments.

Based on the comparison, we propose the concept of a Credibility Loop - a first model of source credibility evaluation by the human brain.