K-pop lyrics have become more positive over the past 30 years

How do you track emotional changes within the population of a country without embarking on large-scale, costly surveys or lab-based studies? One idea is to look for changes in the lyrics of hit songs. When this type of work was conducted in the US, researchers found a rise in negative emotional content over a roughly 30-year time span. Now a new study of South Korean pop ('K-pop') has found the opposite: a shift, from 1990 to 2019, towards more positive, and less negative, emotional content. This could reflect various changes in South Korea in that period, write Wonkwang Jo of Seoul National University and M. Justin Kim of Sungkyunkwan University in Emotion.

The pair used two strategies to analyse the content of almost 3,000 K-pop songs that made the national Top 100 list over those years. First, they used text-mining software to identify adjectives with a clear emotional meaning that were commonly used in the song lyrics. Of the complete list of 27 adjectives, two were classed as positive ('good' and 'pretty'), six were classed as negative (eg 'hurtful' and 'sad'), and the rest were judged to be emotionally neutral. The team looked at how the use of these adjectives fluctuated over the years.

The researchers also used a method known as structural topic modelling to categorise the topics of all these songs. For example, they judged a song that included the words 'breakup', 'pain', 'tears' and 'regret' to be about 'the pain of a break-up'. Again, the pair then categorised each topic as emotionally positive (e.g. 'the feeling of falling in love' or 'a metaphor for freedom'), negative (e.g. 'a breakup' or 'regret'), or neutral.

Their analysis showed that between 1990 and 2019, both positive adjectives and positive topics became more common. At the same time, the proportion of songs about a negative topic decreased.

The trend was less clear when it came to negative adjectives: while two of the negative adjectives ('sad' and 'lonely') became less common, another two ('hurtful' and 'bad') became more common.  One negative topic also increased in frequency ('a description of an end, or anger'). Still, as the team notes, while anger is generally viewed as a negative emotion, it's an active, 'approach' kind of emotion, unlike fear or sadness. And if anger motivates a desirable change — like a fight for justice or the break-up of a 'hurtful', 'bad' relationship — it could be seen as being positive.

The emotional bent of hit songs might well influence how the listeners feel, but the team argues that the relationship also works the other way around: the content of songs probably mirrors the emotions that are dominant within a population. Either way, or both, this new work implies that South Koreans feel more positive now (or in 2019, at least) than they did 30 years ago.

This is certainly different to trends that have been found in the UK and US. Research on more than half a million songs released in the UK between 1985 and 2015 found a downward trend in 'happiness' (though successful songs tended to be 'happier' than less successful songs). And an analysis of the lyrics of hit pop songs in the US between 1980 and 2007 found a reduction in positive emotion, and an increase in angry or antisocial words. The researchers involved in this US work linked the changes in lyrics to a rise in individualistic traits, such as narcissism.

The South Korean researchers think that a rise in individualism helps to explain their findings, too — but, crucially, the two populations started from a different point. While the US was already a highly individualistic nation at the start of the study period, South Korea was not. When an individualistic population becomes even more individualistic, this might lead to a rise in negative traits, the pair suggests. In contrast: "Individualistic values being introduced to a collectivistic society could encourage people to pursue their individual goals and life course, while distancing themselves against potentially excessive obligation to the community."  Also, between 1990 and 2019, South Korea became a markedly richer country. That economic growth may well have contributed to a rise in positive emotions. Data from some other survey-based studies also corroborate the idea that  South Koreans become happier in recent decades, and that this can be linked to economic growth.

Other teams have used different strategies to try to track emotions in large populations. Tweets and Facebook posts have both been analysed, for example. The South Korean researchers believe that this new work, considered alongside similar studies in other countries, shows that songs are rich sources of data, too. "As a cultural product that mirrors the psyche, song lyrics have the potential to be a useful resource for tracking emotions," they conclude.