Revisiting the Effect of Discrepant Perceptual Fluency on Truth Judgments

Fluency theory assumes that perceived truth is influenced by the subjective ease with which presented information is processed. Several studies have demonstrated that increased perceptual fluency, induced by high versus low color contrast of presented statements, results in higher truth judgments. According to the discrepancy-attribution hypothesis, the unexpected switch from several low-fluency stimuli to a high-fluency stimulus is assumed to enhance perceived truthfulness. In two online studies (one preregistered), we aimed to replicate the central finding by Hansen, Dechêne, and Wänke (2008; Journal of Experimental Social Psychology) that discrepancies in color contrast influence truth judgments. Additionally, we extended the original design by varying the length of stimulus blocks presented in low or high color contrast. Contrary to previous findings, neither the level of perceptual fluency nor unexpected discrepancies in fluency affected truth judgments even though high-contrast statements were read faster than low-contrast ones, indicating that processing fluency was successfully manipulated. A meta-analysis combining our two experiments with published studies shows that the effect of perceptual fluency induced by color contrast on truth judgments may not be as robust as previously thought.