Emotional content reduces the cognitive effort invested in processing the credibility of social (mis)information.

Emotionality likely is a key factor affecting our susceptibility to misinformation. However, the mechanisms underlying this observation are not well understood. Specifically, when people derive social information from person-related news, they rely predominantly on emotional content, apparently unperturbed by the credibility of the source. To help explain this bias, we here contrast two hypotheses of information processing reflected in changes in pupil size during news-based judgments: Emotion and cognitive effort. Thirty participants were first exposed to websites of well-known trusted or distrusted news media sources exhibiting headlines about unfamiliar persons, followed by social judgments. As expected, emotional relative to neutral headline contents lead to faster and more strongly valenced judgments. In line with the cognitive effort hypothesis, credibility modulated pupil size with larger pupils for headlines from distrusted sources, however only in response to neutral headline contents. Source credibility did not modulate pupil size in response to emotional headline contents. Instead, pupil size was smaller for emotional compared to neutral headlines for both trusted and distrusted sources. This pattern of findings suggests that emotional contents yield fluent social judgments that are made with relatively little mental effort-even if based on untrustworthy news. Cognitive resources to evaluate the credibility of news may primarily be allocated when emotional contents providing (false) fluency are not available. This insight into the biases underlying the processing of potential misinformation may be used as a protection against biased opinions and judgments. (PsycInfo Database Record (c) 2024 APA, all rights reserved).