be processed. The experienced processing fluency is a function of formal features of the stimulus, like figure-ground contrast or presentation duration, as well as the perceiver's previous experiences, like earlier exposures or thoughts about associatively related material. Because perceivers are typically unaware of the specific source of visual fluency, they may attribute the experience to any plausible candidate that comes to mind. Thus, they may erroneously infer from fluency that is due to previous exposure that the stimulus is presented for a long duration, or may infer from fluency due to duration that they have seen the stimulus before. This “free floating” nature of the fluency experience explains the broad range of substantive judgments—most notably judgments of truth, familiarity, and liking— for which this experience can serve as a source of information. As is the case for other types of experiential information, people only draw on their fluency experiences when the informational value of the experience for the judgment at hand is not called into question. When people are aware that their experience may be due to a source that is unrelated to the object of judgment, the otherwise observed influence is attenuated or eliminated.
On the theoretical side, our findings illustrate that analyses of visual persuasion need to consider the interplay of objective features of the stimulus, the context in which the stimulus is presented, and the perceivers' subjective experiences. On the applied side, our findings indicate that easy-to-process messages are more appealing and persuasive. Many of the variables that facilitate processing are well known to practitioners, like figure-ground contrast, clarity, symmetry, and proportion. Other variables, like priming procedures or the match between stimulus and context, have received limited attention in the applied domain. Their systematic exploration promises a fruitful avenue for future research at the interface of psychology and visual design.