The photo-truthiness effect: The influence of nonprobative photos on truth judgments in a 2-phase procedure
Date
2025
Authors
King-Nyberg, Bennett
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Truthiness is the belief or assertion that a statement is true based on intuition and subjective perception rather than evidence or critical examination. Recent research has demonstrated that the presence of a nonprobative photo - an image that is related to a claim but provides no direct evidence for it - can increase the probability that a person will judge the claim as true. This photo-truthiness effect is hypothesized to occur because such images enhance processing fluency, making the claim easier to process and bringing related concepts to mind. This increased fluency is then misattributed to familiarity and truth, making people more likely to judge the statement as true. In most photo truthiness studies, participants evaluate claims in a 1-phase procedure, whereby they see a claim with or without an accompanying photo and immediately judge its veracity. This design facilitates processing of both the claim and the photo simultaneously, potentially leading some to discount the photo’s influence. The present research introduces a 2-phase procedure, in which participants first view trivia claims with or without an associated photo and only later, in a separate phase, judge the truth of those claims in isolation. This temporal separation of photos and judgements was designed to reduce awareness of the photo’s influence when judging claims, thereby increasing the photo-truthiness effect. It also introduces a repetition of the claims, which has previously been shown to increase the likelihood that they are judged as true. Across six preregistered experiments, the effect of separating photo presentation from truth judgments on the truthiness effect was tested. Results confirmed that claims with photos were more often judged as true than claims without photos. However, the 2-phase procedure did not produce a significantly larger effect than the 1-phase procedure in any of the experiments nor in an analysis across experiments. Item-level analyses revealed that some statements were more susceptible to truthiness effects than others, and in some cases, the presence of a photo even reduced reported truth (a “falsiness” effect). Response time analyses provided some support that truth judgments were more strongly influenced by photos when participants made rapid decisions, consistent with the idea that truthiness is driven by fluency rather than deliberate reasoning. These findings suggest that the cognitive mechanisms underlying truthiness - such as fluency and source-monitoring errors - are robust across presentation formats, and that the strength of the effect may depend more on the characteristics of individual items than on when photos are presented.
Description
Keywords
truthiness, fluency, heuristic, nonprobative, photo-truthiness effect