Although it is not associated with any apparent biological advantagess or useful value (such as money), music is ranked among the highest sources of pleasure. Music's important role in our society and culture has led to the assumption that its ability to induce pleasure is universal. However, this assumption has never been empirically tested.
On an article published on 6 March in the journal Current Biology, researchers from the University of Barcelona and the Bellvitge Biomedical Research Institute (IDIBELL) affirm that music does not speak to everyone and describe a new condition referred as specific musical anhedonia, that is, the specific inability to experience pleasure from music.
UB and IDIBELL researchers found hints about this form of anhedonia on a previous study that included the development of a questionnaire to evaluate individual differences in musical reward. Those evaluations found some individuals who reported low sensitivity to music but average sensitivity to other kinds of reward.
Current study was developed with three groups of ten people each with high, average or low sensitivity to musical reward. All they were healthy individuals with normal perceptual function. Participants performed two different experiments: a music task and a monetary incentive delay task. Both, music and monetary rewards activate the same regions of the reward system. Meanwhile, researchers recorded other physiologic indicators of emotion, for instance changes of skin conductance response and heart rate.
"Results show that healthy individuals, without diseases associated with the reward system and normal musical perception capacities, do not have an emotional response to music", explains Josep Marco Pallarès, researcher from the Department of Basic Psychology of UB and IDIBELL. "The identification of these individuals could be very important to understand the neural basis of music; in order words, to understand how a set of notes is translated into emotions," points out the expert.
The human reward system is a complex network that involves several brain regions (to be exact it is located at ventral striatum, amygdala, and ventromedial prefrontal cortex, among other regions), but the reward value of music is also determined by functional connectivity between ventral striatum and auditory cortices, as well as the frontal regions. Therefore, "results suggest that musical reward depends not only on the engagement of the mesolimbic structures, but also on how this network interacts with other cortical regions related to music", highlights Marco.
The idea that people can be sensitive to one type of reward and not to another suggests that there might be different ways to access the reward system and that, for each person, some ways might be more effective than others. Findings also reveal that it is not a particular preference for one type of music over another, but an inability to derive pleasure from an entire domain, music, which the vast majority of human populations do find pleasurable.