“When we looked at millions of books published in English every year and looked for a specific category of words denoting unhappiness, we found that those words in aggregate averaged the authors’ economic experiences over the past decade. In other words, global economics is part of the shared emotional experience of the 20th century,” said study author Alex Bentley, a professor at the University of Bristol in a statement.

They reported that market economic misery corresponds with WW1, the aftermath of the Great Depression, and the energy crisis of 1975. The literary misery comes about a decade later, which the researchers speculate could be due to the time gap between when a writer was young and live through these experiences and formed these memories, to when they actually began writing published work.

The researchers even repeated the study with books written in German, and found the same connection.