Music is widely used in our everyday lives, in everything from school bells and ringtones to advertisements and films. It helps regulate negative moods and emotions, and is used in clinical settings to promote physical and mental health.
The benefits of listening to music are well known. However, there is very little research at the moment, if any, about the relationship between music during sleep and emotion. Does listening to music while you are asleep affect your mood?
To find it out, I conducted an experiment this summer under the Addicted to Discovery programme, a research project offered by the university. My study focused on whether music controls the levels of happiness when people are sleeping.
Four pieces of instrumental music were chosen for the experiment in line with previous studies and an opinion poll conducted by the BBC.
The pieces by Beethoven and Mozart were mostly played at a fast tempo, and sounded joyful. In contrast, the music composed by Samuel Barber and Mahler had a slow tempo, which sounded rather sad.
To measure the influence of music on people's mood, I included 28 items from the Oxford Happiness Questionnaire in my questionnaire. Each item consisted of a positive or negative statement which could be evaluated on a uniform six-point Likert scale, in which "1" signified "strongly disagree" and "6" indicated "strongly agree". The sum of the item scores reflected the respondent's level of happiness, with higher scores indicating greater happiness.
Fifteen participants aged between 18 and 24 were equally divided into three groups: the control group without music; the experimental group with happy music; and the experimental group with sad music. They were asked to answer the first half of the questionnaire (numbers 1 to 14) before taking a 20-minute nap on an air mattress. Once they had fallen asleep, instrumental music at a level of not more than 50 decibels was played, depending on the group the person belonged to, during the entire time they were asleep. They were woken 20 minutes later and were asked to complete the remaining questions (numbers 15 to 28).
By comparing the differences in scores before and after sleep, an individual's emotional changes were revealed.
Surprisingly, according to the results, participants generally reported to be less happy after exposure to happy music during sleep. Compared to the control group in which the average level of happiness increased slightly by 0.2 after sleep, the happy-music group's score fell by 1.2 points. As for the sad-music group, however, there was a substantial jump by 5.6 points. It was also noted that participants who listened to sad music were consistently found to be happier.
Though these were preliminary findings, they showed that music could affect our moods during sleep. So the next time you feel unhappy, why don't you play some sad music while you are asleep?
Helle Cheng Hiu-ying, a Year Two student in Translation and Interpretation, City University of Hong Kong