To what extent can simple contextual events affect preference? In this study, three tests were applied to assert whether contextual unpredictability has a negative effect on preference for novel visual items. By asking subjects to rate their first impressions of novel brand logos while playing simple sounds, study 1 shows that brand logos coupled to unpredictable sounds were rated less favorably than logos presented with a predictable sound. In Study 2, this effect is found to be equally strong for abstract art paintings. Finally, Study 3 demonstrates that the negative effect of unpredictable sounds on preference is associated with a stronger arousal response, as indexed by pupil dilation responses. These results suggest that unpredictable sounds engage an emotional response that affects the first impression of a concurrently presented visual object. We discuss these findings in light of the basic psychology and neuropsychology of preference formation.