Music is not only able to affect your mood -- listening to particularly happy or sad music can even change the way we perceive the world, according to researchers from the University of Groningen.

Music and mood are closely interrelated -- listening to a sad or happy song on the radio can make you feel more sad or happy. However, such mood changes not only affect how you feel, they also change your perception. For example, people will recognize happy faces if they are feeling happy themselves.

A new study by researcher Jacob Jolij and student Maaike Meurs of the Psychology Department of the University of Groningen shows that music has an even more dramatic effect on perception: even if there is nothing to see, people sometimes still see happy faces when they are listening to happy music and sad faces when they are listening to sad music.

Smileys

Jolij and Meurs had their test subjects perform a task in which they had to identify happy and sad smileys while listening to happy or sad music. Music turned out to have a great influence on what the subjects saw: smileys that matched the music were identified much more accurately. And even when no smiley at all was shown, the subjects often thought they recognized a happy smiley when listening to happy music and a sad one when listening to sad music.

Expectation

The latter finding is particularly interesting according to the researchers. Jolij: 'Seeing things that are not there is the result of top-down processes in the brain. Conscious perception is largely based on these top-down processes: your brain continuously compares the information that comes in through your eyes with what it expects on the basis of what you know about the world. The final result of this comparison process is what we eventually experience as reality. Our research results suggest that the brain builds up expectations not just on the basis of experience but on your mood as well.'

The research was published in the open access journal PLoS ONE on 21 April.