processing-fluency

How easy the mind finds it to process something — a font, a face, a melody, an idea. The easier it feels, the more beautiful, true, and familiar it seems.

Processing fluency is the shared engine behind beauty-as-fluency (what feels smooth feels beautiful), the mere-exposure effect (what you've seen before feels easier, so you like it more), and the illusion-of-truth (what reads smoothly feels more credible). It is also the mechanism behind the PIA model's pleasure route: pleasure arises from the gut-level ease of processing a fluent stimulus, while interest arises from the effortful process of reducing disfluency.