Music affects the human brain in endless ways. From experiencing pleasure and joy to sound, to remembering autobiographical events, to communicating through movement, music impacts humans constantly and significantly.

In a recent study published in February in Scientific Reports—led by Cognitive Psychologist and Professor Dr. Daniel Levitin—sex, drugs, and music were all shown to operate in the same reward pathway in the brain—showing how musical pleasure compares to the pleasure received from sex and drugs. According to PhD candidate and co-author of the paper, Adiel Mallik, this system is known as the dopamine-opioid pathway.

“The drug naltrexone blocks the mu-opioid receptor, which is responsible for experiencing euphoria and pain relief,” Mallik said.

In the study, the participants who were administered naltrexone reported a dulling of their overall emotions—even after they were asked to listen to their self-identified favourite songs.

“One [participant] said, ‘I know this is my favourite song, but it doesn’t feel like it usually does,’” Levitin said of a report he received from a study subject. “Another [reported], ‘It sounds pretty, but it’s not doing anything for me.’”

But the effects don’t end there. The team also investigated the impact of naltrexone on zygomatic activity—also known as ‘smiling’ activity—and corrugator activity—a muscle activated while frowning. Subjects were connected to a facial electromyogram—used to measure emotional expression.

“What I found interesting was that we expected the zygomatic activity to go down, but the corrugator muscle activity also went down, so there was a positive and negative emotional response,” Mallik said.

The opioid blockage thus made people both frown and smile less, having an overall neutralizing impact on participants. The team was surprised to find that the feelings shown by the subjects towards their favourite songs was emptiness, as opposed to experiencing pure negativity. Imagine an all-time favourite song, one that previously evoked joy and emotional intensity, eliciting no feelings.

Opioids are, however, often associated with addictive behaviours, which can cause damage to an individual’s life and those around them. Thus, research toward understanding the complex interactions between neurochemical roots of pleasure may help neuroscientists address addiction as an issue.

Emotion inspired by music can also be visibly seen and comprehended. A study published last April in Emotion, conducted by Steven Livingstone, a former postdoctoral fellow in McGill’s Department of Psychology, and Dr. Caroline Palmer, McGill psychology professor and Canada Research Chair in Cognitive Neuroscience of Performance, showed that singers and performers can express their emotions when they move their bodies—their head signals carry information to the audience before any sound is even made.

“We know from how singers sing that they are very expressive when they move their bodies, and head movements of singers and of speakers carry a lot of information—even before they start making sound,” Palmer explained.

The study showed that subjects possessed the ability to judge emotion based on head movements alone, without the addition of sounds or expressions. This ability allows situations to be analyzed where no discernable music or sound persists, such as in a noisy club, or observing others in conversation.

Clearly, music contributes to human emotion and the display of emotion; however, it can reach further and influence one’s personal identity.

“Music is a powerful trigger to thinking about the past,” Dr. Signy Sheldon, assistant professor in the Department of Psychology, said.

In her February 2017 study, entitled “More than a feeling: Emotional cues impact the access and experience of autobiographical memories,” Sheldon explores what characteristics of music stimulate memory: Is the song itself what sparks an image from the past, or is it the characteristics of music as a whole?

As Levitin’s study shows, music influences current mood and feelings. Sheldon focuses on how music can turn on different aspects of emotion, allowing for memory conjuration.

To investigate this question, participants in Sheldon’s study listened to unfamiliar, classical, scientifically-developed music that evoked different emotions. The happier music had a major key and was more upbeat, while the sad music samples had minor keys and slower tempos.

Unexpected results arose from this study. Participants accessed memories faster when listening to happy music as opposed to sad, although they had never heard the classical tunes before. In addition, positive music promoted the recollection of positive memories, while the negative music, whether scary or sad, brought negative memories to the surface.

The ramifications of these findings reveal a lot about human nature.

“Past memories help us build our self-identity, or our concept of self,” Sheldon said. “So being able to access memories from past autobiographical events, and access our past personal experiences, to happy music, could mean that we are constantly trying to uphold a happy depiction of our autobiographical selves. Happy music will make us think about ourselves more than any other type of music because of this function of autobiographical memory, to maintain a positive self-identity.”

The fact that the tone of music influences human emotion also highlights key elements of memory retrieval—that it is dynamic and flexible. Accessing our past is not based on personal choice. Rather, our surroundings and the emotions being experienced, control which memories we access.

“This study shows us that we won’t access memories based on what we need, but based on the situation we’re in while we’re remembering,” Sheldon said.

Scientists were able to make this observation after they discovered music’s impact on emotion.

In future studies, Sheldon will research how emotions experienced while listening to music affect learning or the uptake of information. Participants will be presented with complex images while listening to similar musical emotional queues. Eye tracking techniques will be applied to analyze how people digest this information. Sheldon also plans to use brain scanning in order to identify any differences in cortical—or brain—regions while subjects access memories in light of happy cues.

“[The] take-home message is that if you are trying to remind someone of a past event and you want them to remember it in a positive light, play happy music for them,” Sheldon said.

These two studies show the connections between music and emotional cues and how they promote access to memories. The best part of this newly discovered link: The relationship between music and the brain is practically universal. From six-month-old babies to adults with musical and non-musical careers, music recognition and its impact on people works in similar ways.

“Everyone is a skilled foot-tapper. Everyone is a skilled hummer. Everyone is a good clapper-to-the-beat at a concert. And how is that possible?” Palmer asked. “The idea that you can go to a concert and hear a piece of music that you have never heard before and move in time to it is wonderful.”

Every day, music revives memories within us that remind us who we are, and who we want to be—so keep clapping, tapping, and listening.