Reber, R., Winkielman, P. & Schwarz, N. (1998). Effects of perceptual fluency on affective judgments. Psychological Science, 9, 45-48.

Three experiments examined the effects of perceptual fluency on affective judgments. In Exp. 1, higher perceptual fluency was achieved by presenting a matching rather than non-matching prime before showing a target picture. Ss judged stimuli as prettier if the targets were preceded by a matching rather than non-matching prime. In Exp. 2, perceptual fluency was manipulated by figure-ground contrast. Stimuli were judged as more pretty, and less ugly, the higher the contrast. In Exp. 3, perceptual fluency was manipulated by presentation duration. Stimuli shown for a longer duration were liked more, and disliked less. The authors conclude that (a) perceptual fluency increases liking, and (b) the experience of fluency is affectively positive, and hence attributed to positive but not to negative features, as reflected in a differential impact on positive and negative judgments.