The top of the latest New York Times best-seller list features a legal thriller involving suicide and racial strife, a novel centering on a suddenly orphaned boy, and a murder mystery involving two unhappily married women. That's not exactly warm and fuzzy subject matter, but according to one study, the books we read are about to get even darker.
The study, from researchers in the United Kingdom, finds that books' moods correlate strongly with society's economic mood. The researchers created a "literary misery index" by searching Google book data over the years for both sad words ("self-pity," "melancholy," "demoralized," for example) and happy words ("triumph," "gusto," "exuberantly"). That index matched closely with an "economic misery index" that tracks both unemployment and inflation, but with a lag of roughly a decade.
In the below chart, the literary misery index (LM) is shown against a 10-year moving average of the economic misery index (EM).
The results transcend language as well; researchers found similar results, likewise with a decade-long lag, in German books. That specific 10-year gap surprised one author.
"For me, the most surprising finding was that it was specifically a decade moving average of economic misery – not four years, say, or fifteen, but ten or eleven years – that correlates so well with literary misery, in both English and German," says Alex Bentley, a professor at the University of Bristol and the study's lead author, in an email to U.S. News.
For example, when looked at without the 10-year moving average, economic misery hit a peak in the early 1930s, at the height of the Great Depression, books hit peak misery in the early 1940s. Likewise, the economic turmoil of the 1970s and early 1980s doesn't appear to have hit books until the mid-1980s.
Though one can find individual examples of art mirroring economic life – 1939's "The Grapes of Wrath," is one example, having come a decade after the 1929 stock market crash – Bentley says that individual books as responses to the economy are not the point here. While novelists might decide to write directly about characters in an economic crisis, for example, novels are only around 10 percent of the total book sample. Rather, what is more fascinating is that the massive population of books as a whole mirrors the macroeconomy, he says.
"This is not about individual novelists; it's about a statistical pattern at the population scale that no one could be individually aware of: the normalised (sic) frequencies of words in books reflects the moving average of a population scale economic index," says Bentley.
All of which may signal that, come 2018, we should all brace ourselves for a wave of excruciatingly depressing best-sellers.