Actions that feel rewarding typically feel that way because, if we continue them, we are more likely to survive as a species. That's why elements of music puzzle scientists. Music can't make you feel full if you're hungry or help you pass your genes on to the next generation. But music, like all of these things, can still make you feel inexplicably good.
There's something about it that tickles the brain anyway. When that happens, music can ignite literal chills.
By studying the brain activity behind those chills, scientists are getting closer to understanding why music makes us feel pleasure.
In a study released Tuesday, scientists found that specific waves of brain activity increase in power when people get the chills from emotionally moving pieces of music.
The study was conducted on a sample of 18 people and builds off of past research that suggests music is linked to activation of the brain's pleasure centers.
First author Thibault Chabin is a Ph.D. student at The University of Burgundy Franche-Comté in France. He tells Inverse that musical pleasure activates some of the reward processing circuits as other "basal" forms of pleasure do, like food or sex. Listening to music can also lead to dopamine release – the hormone associated with pleasurable experiences, he says.
At the same time, it's not clear why music should have that power of our pleasure systems.
"What is intriguing with music is it seems to confer no biological value and has no value for survival," he tells Inverse. "We need to discover why music can be rewarding and can recruit an ancestral circuit dedicated to motivation and involved in survival function."
The study was published in Frontiers in Neuroscience.
Music and the brain – Past studies on music and pleasure analyzed neurotransmitters and used fMRI imaging to show that music causes two waves of pleasure in the brain. A 2011 study in Nature reported that, when a song's played, there's first a period of anticipation and then, finally, a release. The chills hit and dopamine is released.
This new study is based EEG readings, which measure electrical activity. The idea was to see if there were changes in the brain's electrical activity that could also underpin a relationship between music and pleasure.
Eighteen people were evaluated, eight of whom were amateur musicians. The participants picked five songs ahead of time that they knew often gave them the chills. The scientists also provided the team with three neutral songs to listen to. Then, the listeners sat back, closed their eyes, and listened to the music through wireless headphones while scientists monitored their brain activity.
As they listened, participants got the chills an average of 16.9 times each. Each chilling moment lasted for 8.75 seconds.
When the participants listened to songs that gave them the chills, the team found an increase in theta waves (a wave of brain activity that follows regular oscillations) in the orbitofrontal cortex. This area of the brain is associated with emotional processing.
The study suggests "an ancestral function for music."
The power of those waves correlated with the intensity of chills and the strength of emotions experienced by the listeners.
At the same time, the team found patterns of activity in two other brain regions: the supplementary motor area, a region of the brain involved in motor control, and the right temporal lobe, which is involved in interpreting non-verbal communication, like music.
The authors argue that the increase in theta wave power is the surface-level signal of a two-pronged reward response happening deep in the brain: that buildup — and finally — release of dopamine.
The ancestral function of music — Chabin says it's another indicator that music can trigger the release of dopamine and therefore activate our brain's pleasure systems (not to mention far-flung areas of the brain not related to pleasure). In that way it makes it similar, but not identical to other activities that release dopamine into the brain.
That similarity hints at another function for music that goes beyond simple pleasure, he says. There may be an evolutionary reason that music tickles our brains in a similar way (but not identical) as other basal pleasures.
"The implication of the reward system and of the dopaminergic system in the processing of musical pleasure, [also involved in motivated behavior: feeding, sex, drugs, money] suggest an ancestral function for music."
Chabin suggests that music may have once had another "ancestral function."
In the paper, the authors suggest that the ancestral function might be tied to the "anticipation stage" of the chills. Theta waves are linked to success on memory tasks when we perceive a reward on the other side, in previous studies. The chills could be one way of helping us realize we're on the road to a reward, but this is just an early idea.
Scientists still don't exactly know what that "ancestral function" is — although some do hypothesize it's a socially rooted, biological adaptation. Because music can bond communities, it benefits communities to enjoy music — the question is which part of that equation came first.
Now there's further proof enjoyment of music has its roots in ancient history — roots that can be further untangled with future research.
Abstract: Music has the capacity to elicit strong positive feelings in humans by activating the brain’s reward system. Since group’s emotional dynamics is a central concern of social neurosciences, the study of emotion in natural/ecological conditions gain interest. This study aimed to show that High Density EEG (HD-EEG) is able to reveal patterns of cerebral activities previously identified by fMRI or PET scans when the subject experiences pleasurable musical chills. Participants (11 female, 7 male) were recorded by HD-EEG while listening to their favorite pleasurable chill-inducing musical excerpt; they reported their subjective emotional state from low pleasure up to chills. HD-EEG results showed an increase of theta activity in the prefrontal cortex when arousal and emotional ratings increased, which are associated with orbitofrontal cortex activation localized using source localization algorithms. In addition, two specific pattern of chills has been identified; a decreased theta activity in the right central region could reflect supplementary motor area (SMA) activation during chills, may be related to rhythmic anticipation processing. A decreased theta activity in the right temporal region may be related to musical appreciation. The alpha frontal/prefrontal asymmetry did not reflect the felt emotional pleasure but the increased arousal (frontal beta/alpha ratio) corresponded to increased emotional ratings. These results correspond with fMRI and PET findings, thus confirming that EEG is a reliable method and a promising tool for the investigation of group musical pleasure through musical reward processing.