Every second person says they get “chills” when listening to music they really love. Electroencephalography (EEG) shows electrical activity in the brain when this happens, revealing distinctive patterns across the reward and pleasure centers that help explain the phenomenon.
The power music has over us is an ongoing source of puzzlement to neuroscientists. There are easy evolutionary explanations for most of our other sources of pleasure. Some were crucial to our ancestors' survival. Others – like many drugs – mimic the effects of things we needed. It's much harder to see why music matters so much, yet we know it does. As neurologist Oliver Sacks powerfully demonstrated, its hold on us can remain when accident, tumor, or decay have destroyed many of the other functions of the mind.
For many, that takes the form of a shiver running up the spine in response to a particularly beloved chord. Thibault Chabin of the Université de Bourgogne Franche-Comté recruited 18 people who experience this frequently and asked them to identify pieces of music that work this magic on them. They also marked when in the piece the chills occured and rated their strength.
Chabin then hooked his subjects up to EEGs and played their chosen music to them, having them note when they experienced a chill. In Frontiers in Neuroscience, Chabin reports wide variations in the self-described chill length. For one individual, the average was just 0.2 seconds, while another's typically lasted 80 times that.
"Participants of our study were able to precisely indicate "chill-producing" moments in the songs, but most musical chills occurred in many parts of the extracts and not only in the predicted moments," Chabin said in a statement. The chills were accompanied by bursts of electrical activity in the orbitofrontal cortex, the supplementary motor area and the right temporal lobe. The last of these is specifically involved in auditory processing and music appreciation, but the other two are known for emotional processing and movement control, respectively.
The chills were associated with two specific patterns. In both cases, theta wave activity decreased in the right central region and right temporal region of the brain. Chabin and co-authors think the first is associated with the anticipation of a particularly beloved musical sequence, while the second reflects an appreciation of the music as it is experienced.
"Contrary to heavy neuroimaging techniques such as PET scan or fMRI, classic EEG can be transported outside of the lab into naturalistic scenarios," Chabin said. Being stuck in the claustrophobic environment of an MRI machine might have a dampening effect on any enjoyment.
In an effort to explain why music affects us so powerfully, Chabin has proposed the anticipation, rather than the sounds themselves, may serve some evolutionary purpose.