Mood, music, and caffeine

What we see is affected by how we feel: in positive moods, we are more sensitive to positive stimuli, such as happy faces, but in negative moods we are more sensitive to negative stimuli, such as sad faces. Caffeine is known to affect mood - a cup of coffee results in a more positive mood, but also affects contrast perception. In this study we investigated whether the effects of mood and caffeine on perception interact. We let observers do a challenging face detection task whilst they were listening to happy, sad, or no music to manipulate their mood, in two conditions, one with caffeine consumption and one with placebo consumption. We observed a siginifant music x caffeine interaction: caffeine increased the effects of happy music, but decreased the effects of sad music on positive mood. Moreover, we replicated our earlier finding that mood alters perception. In addition, we found that caffeine, apart from increasing perceptual contrast, attenuated the effects of mood on perception. Together, these results reveal some of the interactions between the different methods people use to alter their mood (i.e., music and coffee), and how these effects change the way we perceive the world.