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Category: Project

Description: This study investigates how different information environments—that did, or did not, mix false with true information—affect vaccination belief accuracy, confidence in these beliefs, and vaccination attitudes in a large Signal Detection Theory experiment (N = 2,100). Results revealed common and distinct effects across misinformation environments. First, vaccination misinformation exposure consistently shifted both truth discernment (d’; reducing participants’ ability to differentiate truth from falsehood) and response bias (c; increasing overall gullibility). Second, vaccination misinformation consistently raised False Positives (accepting falsehoods), with minimal impact on Misses (rejecting truths), and this pattern extended to metacognitive judgments, where misinformation selectively increased confidence in believing falsehoods without diminishing confidence in truths. Third, differential effects of information environments emerged primarily in relation to belief accuracy: Exclusively false environments most effectively impaired truth discernment (d’), while environments mixing truths with logically inconsistent falsehoods (“bullshit” environments) most effectively shifted response bias (c), fostering generalized gullibility.