De Vries, M., Holland, R.W., Chenier, T., Starr, M.J., & Winkielman, P. (2010). Happiness cools the warm glow of familiarity: Psychophysiological evidence that mood modulates the familiarity-affect link.  Psychological Science, 21, 321–328.

People often prefer familiar stimuli, presumably because familiarity signals safety. This preference can occur with merely repeated old stimuli, but it is most robust with new but highly familiar prototypes of a known category (beauty-in-averageness effect). However, is familiarity always warm? Tuning accounts of mood hold that positive mood signals a safe environment, whereas negative mood signals an unsafe environment. Thus, the value of familiarity should depend on mood. We show that compared with a sad mood, a happy mood eliminates the preference for familiar stimuli, as shown in measures of self-reported liking and physiological measures of affect (electromyographic indicator of spontaneous smiling). The basic effect of exposure on preference and its modulation by mood were most robust for prototypes (category averages). All this occurs even though prototypes might be more familiar in a happy mood. We conclude that mood changes the hedonic implications of familiarity cues.