If scent has a hotline to memory, it seems music has a hotline to emotion.

By Marko Ahtisaari and Ketki Karanam

Music has the power to stimulate strong emotions within us, to the extent that it is probably rare not to be somehow emotionally affected by music. We all know what emotions are and experience them daily. Most of us also listen to music in order to experience emotions. The specific mechanisms through which music evokes emotions is a rich field of research, with a great number of unanswered questions. Why does sound talk to our emotional brain? Why do we perceive emotional information in musical features? Why do we feel the urge to move when hearing music? Through increasing scientific understanding of the universal as well as the individual principles behind music-evoked emotions, we will be able to better understand the effects that music-listening can have and make better use of them in an informed manner. 

Perhaps the primary reason for music listening is the power that music has in stirring our emotions. Music has been reported to evoke the full range of human emotion (1, 2): from sad, nostalgic, and tense, to happy, relaxed, calm, and joyous. Correspondingly, neuroimaging studies have shown that music can activate the brain areas typically associated with emotions (3): the deep brain structures that are part of the limbic system like the amygdala and the hippocampus as well as the pathways that transmit dopamine (for pleasure associated with music-listening). The relationship between music-listening and the dopaminergic pathway is also behind the “chills”  that many people report experiencing during music-listening. Chills are physiological sensations, like the hairs getting raised on you arm, and the experience of “shivers down your spine” that accompany intense, peak emotional experiences.

However, we don’t always listen to music to be moved - sometimes people use music for other effects. For example, many people listen to music to help them concentrate or do better in a demanding cognitive task. In spite of this, it is suspected that many of the cognitive benefits people experience from music listening actually stem from its effects on emotions, because positive affect can improve cognitive performance. So even though you might not be selecting for music that induces the “chills” effect but just something to help you get stuff done, the way that music strums your emotions may still be at the root of why it helps. Thorough understanding of the connections between the emotional and physiological effects of music listening and health requires more study because the context for the emotional effects of music listening on individuals are so varied. Large-scale data on listening, performance and context would be needed to identify bigger patterns in the connections between music, emotions, and cognitive performance. 

Even with free music streaming services, people still spend a lot of money on music and our emotional brain is responsible for the toll that music takes on our wallets. In an interesting study published in the acclaimed journal Science, researchers found that the amount of activation in the area of the brain linked with reward and pleasure predicted how much money a person would be willing to spend on a new, previously unheard piece of music (4.) The valuation of a new musical piece included activation of areas of the brain that process sound features, the limbic areas associated with emotions, and prefrontal areas, associated with decision-making. Increasing activity in the functional connections between these areas and the nucleus accumbens, associated with motivation, pleasure and reward, was connected to the willingness to spend more money on the musical piece. The study elegantly described how processing of sound results in activation of affective brain regions and ultimately influences decision-making.

Music can also have more fine-grained effects on purchasing behavior and influence decision-making regarding products other than music. In a relatively unknown and somewhat concerning study for the free-willed person (5), playing characteristically French music in a wine shop increased sales for wines originating from France and or characteristically German music increased sales of wines from Germany. In another study (6), playing classical music versus pop music in a wine shop made people choose and purchase more expensive wines. Are people really this impressionable? Probably not. It is certain that hearing a certain type of music won’t make a person purchase something they absolutely do not want. This power that music can have in influencing our decisions may speak in part for the contextual nature of cognition. And the big role that music can have as part of your everyday life. 

So what underlies all the effects that music has on our emotions, thoughts, and even decision-making? How is it possible that something that is basically organized sound can bring us to tears, move us, and convey deep emotional messages within its very structure? Scientific investigation of the mechanisms behind music-evoked emotions is a rich field of enquiry within the psychology and neuroscience of music. In recent decades, a number of attempts (7,8) at describing these mechanisms and principles have been made. Many theories on mechanisms that stir up emotions described by scientists are familiar to us all, but some are perhaps more surprising. For instance, the role of memories in music-evoked emotion is quite a familiar to most people: many people have break-up songs - pieces they listened to during that emotional time and that can instantly bring on the emotional state experienced during the break-up even at a later time. But did you know that researchers also speculate that music may convey emotional information by activating the mirror neuron system? Or that your brain is very adept at processing complex musical structure, even if you’ve never laid hand on an instrument? 

When two people interact, numerous mechanisms are at play that create a connection between the individuals. For instance, without knowing it, people often tend to mimic each other’s postures and speech styles during discussion. Also emotions are contagious:  according to a study (9), exposure to pictures of facial expressions of emotions activated the same facial muscles needed to produce a similar expression and led to reports of experiencing similar feelings in the observers. Astonishingly, this happened even if the pictures were shown so quickly that the observers didn’t experience a conscious perception of the photo. 

This mimicking and contagion of emotions may rely in part on the putative human mirror neuron system: neurons that are active when you produce a certain movement but also when someone else does the same - neurons to which you and other people are the same person. A rich amount of emotional information is conveyed through movement, including prosody, posture and facial expressions. Activation of the mirror neuron system by these movements may help us understand other’s emotions, since we are modeling the movements related to emotional expression as they were our own. 

Where does the music come in, then? It is suspected that mirroring and resulting emotional contagion does not only happen between people but also during music listening. It sounds quite incredible, but it is possible that emotional expression in music could also be mirrored by the brain and then give rise to the corresponding emotional state in the listener. For instance, music could be perceived as sad because of the commonalities it has with the prosody of sad speech (low pitch, low volume, slow, dark timbre [9].) 

Humans are one of the extremely few species that can synchronize their body movement to music (even babies do it - take a look at this popular video clip of !). Brain imaging studies have shown that the motor areas of the brain are active even during passive listening to musical rhythms without any movement (11). It has been said that music prepares people for movement. But how is this special property of music connected to the experience of emotions? 

It has been proposed (12) that the aforementioned human mirror neuron system could in fact also encode the movements conveyed by melodies. This would mean that the system might process movement in music like physical movement. In other words, an upward going melody would be processed in the brain as upward movement. And as upward movement is typically related to experiences like jumping for joy, this mirroring in the brain (however, without overt movement) would contribute to the recognition and experience of the emotion conveyed by the music. 

It also seems that acoustic features of music as well as characteristics of physical movement may be universally interpreted to represent specific emotions. An intriguing study (13) compared how subjects from the US and from an isolated tribe in Cambodia that had never been exposed to Western music, experienced the emotion expressed by acoustic properties of melodies and the movement characteristics of an animated ball. Subjects were asked to manipulate the melodies and the movement of the animated ball for their tempo or rate of bouncing, direction of movement and so on (to best match a specific basic emotion like fear, happiness, sadness and anger). The study found that similar physical movement of the ball and similar movements in music represented the same emotions regardless of the subjects’ exposure to Western music (for example, up either as movement or as a melody increasing in pitch would tend to be related to happy instead of sad). 

In summary, movement, be it in musical or physical form, is one important way of conveying emotions. Thus, people who say that they are moved by music are more right than they realize!

Very few people consider themselves experts in music or knowledgeable about all the intricacies of music theory. Irrespective of this, all people have the basic neural mechanisms needed to automatically perceive and analyze the structure and rules of music. Irrespective of the level of music training, the brain can perform complex analytical operations on musical information (14); and even without explicit music training, people very quickly learn the regularities typical for the music that they are exposed to: the keys, the ways that certain chords follow each other, and how melodies typically start and end (15.) Therefore, through mere exposure, people learn to predict and anticipate the movements of the music. Pleasure from music may partly stem from expectations that are based on musical regularities and the way these expectations are fulfilled or violated as the composition unfolds in time as well as the tension experienced while waiting for this resolution. In fact, dopamine levels have been found to peak before the release of this tension created by music, that special moment in a melody that gives you the “chills” (16.) 

All in all, music-evoked emotions are a complex phenomenon that tap into many of the same mechanisms as other emotion-evoking phenomena. Obviously, there is in most cases a clear distinction between the two. Otherwise, listening to sad music might make a person always utterly despondent. Why is it then that sad music, and the sad feelings that it evokes, are still a pleasurable experience for the listener? It has been suggested that this could be due to the fact that similar to the endorphins the body releases in response to physical pain (responsible for the “runner’s high”), emotional pain results in the release of a hormone called prolactin, causing feelings of gratification and relaxation (10.) Perhaps the greatest gift of music lies in its capacity allow people to experience emotions without the burden of having to experience the life events that lead to them. We can experience even extreme emotions in a controlled manner, at will, in comfortable circumstances. 

Investigation of the vast array of processes that are suggested to underlie music-evoked emotions will surely continue to keep scientists busy in the future. Uncovering the ways in which music evokes emotion will provide revelations into why music has such power in influencing listeners, and shed light on the interplay between physiological, cognitive, social and cultural factors in music-evoked emotions. Understanding the connections between these functions would help us use music in an informed way, for example to help cognitive functioning and emotional wellbeing. Importantly, the science will give insight into how the emotional effects of music could be more systematically harnessed to develop clinical applications. 

By Marko Ahtisaari and Ketki Karanam

References

1. Juslin, P. N., & Laukka, P. (2004). Expression, perception, and induction of musical emotions: A review and a questionnaire study of everyday listening. Journal of New Music Research, 33, 217–238. 

2. Zentner, M., Grandjean, D., & Scherer, K. R. (2008). Emotions evoked by the sound of music: Characterization, classification, and measurement. Emotion, 8(4), 494–521. 

3. Koelsch, S. (2014). Brain correlates of music-evoked emotions. Nature Reviews Neuroscience, 15(3), 170-180.

4. Salimpoor, V. N., van den Bosch, I., Kovacevic, N., McIntosh, A. R., Dagher, A., & Zatorre, R. J. (2013). Interactions between the nucleus accumbens and auditory cortices predict music reward value. Science, 340(6129), 216-219.

5. North, A. C., Hargreaves, D. J., & McKendrick, J. (1997). In-store music affects product choice. Nature.

6. Areni, C. S., & Kim, D. (1993). The influence of background music on shopping behavior: classical versus top-forty music in a wine store. Advances in consumer research, 20(1), 336-340.

7. Koelsch, S. (2015). Music‐evoked emotions: principles, brain correlates, and implications for therapy. Annals of the New York Academy of Sciences, 1337(1), 193-201.

8. Juslin, P. N., & Västfjäll, D. (2008). Emotional responses to music: The need to consider underlying mechanisms. Behavioral and brain sciences, 31(05), 559-575.

9. Dimberg, U., Thunberg, M., & Elmehed, K. (2000). Unconscious facial reactions to emotional facial expressions. Psychological science, 11(1), 86-89.

10. Huron, D. (2011). Why is sad music pleasurable? A possible role for prolactin. Musicae Scientiae, 15(2), 146-158.

11. Chen, J. L., Penhune, V. B., & Zatorre, R. J. (2008). Listening to musical rhythms recruits motor regions of the brain. Cerebral cortex, 18(12), 2844-2854.

12. Overy, K. & I. Molnar-Szakacs. 2009. Being together in time: musical experience and the mirror neuron system. Music Perception. 26: 489–504.

13. Sievers, B., Polansky, L., Casey, M., & Wheatley, T. (2013). Music and movement share a dynamic structure that supports universal expressions of emotion. Proceedings of the National Academy of Sciences, 110(1), 70-75.

14. Tervaniemi, M. (2001). Musical sound processing in the human brain. Annals of the New York Academy of Sciences, 930(1), 259-272.

15. Koelsch, S., Gunter, T. C., Friederici, A. D., & Schröger, E. (2000). Brain indices of music processing:“nonmusicians” are musical. Journal of Cognitive Neuroscience 12(3), 520-541.

16. Salimpoor, V. N., Benovoy, M., Larcher, K., Dagher, A., & Zatorre, R. J. (2011). Anatomically distinct dopamine release during anticipation and experience of peak emotion to music. Nature Neuroscience, 14(2), 257-262.