What are we reading? The emotional trend in 20th century books

cats are reading a book

cats are reading a book (Photo credit: Catunes)

Now there have been trends and there are new ones emerging with the release of every new Bestseller Lists. So, in this huge dynamics of book genre trends, it is worthwhile to know –

Which moods, or emotions, have been popular in the literature of the 20th century? 

Do the various world events happening around us affect our book choices too?

Are the claims that  Twitter mood words can predict stock market trends true ?

Can we glean at our past and see whether our mood patterns have reflected world changes?

Recently, an interesting piece of research came to answer these questions of mine. PLoS One an open access, peer reviewed journal published a research paper  by Alberto Acerbi and other co-researchers  titled – The Expression of Emotions in 20th Century BooksAs i said earlier their aim was to understand

To find out, researchers created six categories of words to express anger, disgust, fear, joy, sadness and surprise.

To do this they use Google’s excellent Ngram viewer, a phrase-usage graphing tool which charts the yearly count of selected n-grams (letter combinations)[n] or words and phrases,as found in over 5.2 million books digitized by Google Inc (up to 2008). Using this, the researchers looked at all English language literature published between 1900 & 2000.Apart from this, they used additional datasets for analysing mood words used in English fiction.

Figure 1. Historical periods of positive and negative moods.

So, lets look at the results starting from the above figure. It shows that moods tracked broad historical trends, including a ‘sad’ peak corresponding to Second World War, and two ‘happy’ peaks, one in the 1920’s and the other in the 1960’s. In more recent years we can see a ‘sad’ period starting from the 1970’s, with an increase in ‘happiness’ in the last years of the data set. Interestingly, the First World War does not seem to register a particular change in mood words.

Figure 2. Decrease in the use of emotion-related words through time.


The second part of results is shown in the above figure. It indicates that the usage of the mood words have decreased in books published in the 20th century. One thing which is indeed highly curious is that the use of words relating to disgust has declined the most. Another strange trend is that the use of fear-related words decreased until the 1970s, when the trend took a sharp turn upwards (and has continued to climb for the next three decades).

For me, it is indeed quite a surprise since it gives a fresh perspective on the last century. However, this sort of detailed use of word data to characterize the evolution of cultural differences and trends, to detect patterns previously unknown through conventional history is quite an exciting way to look into human cultural dynamics.

So, Yay for more such research !!


More to read about:

1). Acerbi A, Enquist M, Ghirlanda S (2009) Cultural evolution and individual development of of openness and conservatism. Proceedings of the National Academy of Sciences USA 106(45): 18931–18935.

2). Nettle D (2007) Language and genes: A new perspective on the origins of human cultural diversity. Proceedings of the National Academy of Sciences USA 104: 10755–10756.

3). Evans N, Levinson SC (2009) The myth of language universals: Language diversity and its importance for cognitive science. Behavioral and Brain Sciences 32: 429–492.

4). Bollen J, Mao H, Zeng X-J (2011) Twitter mood predicts the stock market. Journal of Computational Science 2: 1–8.



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