Researchers have found that the opioid system, responsible for pleasure from natural rewards and drugs, is also needed for the enjoyment of music
Music and drugs activate the same circuits in our brains, according to a new study published last week in Science Reports. The researchers blocked the brain mechanisms that make us feel the reward of drugs and sex. The results suggest that without these mechanisms, we cannot enjoy music either.
The study measured the reaction of the participants when they were listening to different songs. Some of the participants took naltrexone, a drug used to treat alcohol and drug addictions. Under the effects of naltrexone, we cannot feel the reward of a pleasant activity.
The results of the experiment confirmed the hypothesis of the researchers: the participants under effects of the naltrexone did not enjoy the music as much as the other people. The researchers went one step further: they played songs that do not elicit any feelings. Compared to the reaction to the music of their choice, the response of the participants to neutral music was lower in both the participants under the effects of naltrexone and the other participants. But even with the neutral songs, the participants who took the drug had a less significant reaction when compared to the participants who did not take the drug.
The musical choices… included songs by Pink Floyd and David Ghetta, but also works by Mozart and Mahler.
A key element of the study is that the participants had freedom to choose the recordings to listen. The musical taste varies among people, and the researchers wanted to ensure that each participant enjoyed the music. The scientists instructed the participants to choose their favorite songs, or songs that inspired feelings to them.
The musical choices of the participants ranged over different styles. The recordings included songs by Pink Floyd and David Ghetta, but also works by Mozart and Mahler. The researchers looked for neutral songs in previous studies.
The researchers took two sets of measurements to evaluate the response of the subjects of the study. First, each participant controlled a sliding scale from 0 to 100. The higher the value, the more she or he was enjoying the song. At the same time, the researchers measured the physical response, looking for reactions like smiling, frowning or tapping.
the researchers measured the physical response, looking for reactions like smiling, frowning or tapping.
Naltrexone, the drug used for the experiment, targets a series of brain mechanisms known as the pioid system. Several studies suggest that when the opioid receptors are blocked, we cannot experince pleasure. In animals, neuroscientists verified this hypothesis for the pleasure that comes from eating and sex. But animals do not enjoy music as humans do.
The study is the product of a combined effrot from several departments at McGill University, in Canada. The lead author A. Mallik is a PhD candidate in neuroscience, and he worked alongisde members of the deparments of psychology and behavioural neuroscience.
The results suggest a question in the study of human evolution. Like in the proverbial chicken and egg problem, there are two possible scenarios: did humans evolve to enjoy music, or was the music created to exploid the reward mechanisms in our brain? Further research will be required to answer the question.