When the Great Recession produced a new age of hopelessness, artists responded with attempts to process it. Anne Enright's The Forgotten Waltz and Donal Ryan's The Spinning Heart were just two of the many ruminative novels spawned by the downturn, much like John Steinbeck's The Grapes of Wrath sorted through the depths of American poverty after the Great Depression. Throughout good times and bad, the economy hangs an emotional backdrop against which authors of certain eras can't help but write.

But the economy's effect on culture might be stranger and more subtle than previously thought. Terry F. Pettijohn II, a professor of psychology at Coastal Carolina University, has researched the correlations between the economic climate and popular culture for over a decade. He was the lead author of a 2012 study that found that during prosperous times, the most popular American music has a more upbeat tempo and uses more-familiar key signatures—two marks of celebratory, fun tunes—than hit songs released during downturns.

Pettijohn has also catalogued the facial features of several eras' most beloved celebrities, which has led him to propose a theory: The economy might have a lot to do with the types of faces the public is drawn to in any given era.

Pettijohn put out a study, published online last April in Current Psychology, that tested his hypothesis in the realm of country music. His research team measured the faces of the most popular country artists every year from 1946 to 2010, as calculated by Billboard, and compared them to an economic index that accounts for the unemployment rate, the consumer price index, the suicide rate, and several other indicators of "hard times." The results of this analysis suggest that the worse off the economy is, the more likely it is that the most popular country singer has facial features associated with maturity, such as small eyes and a large chin. When things are rosier, breakout singers's features tend to be closer in resemblance to those of infants.

Top Country Singers' Eye Widths vs. the State of the Economy, from 1946 to 2010

Pettijohn et al.

For example, Johnny Cash—who has larger eyes and a smaller chin than most country singers—had a number-one hit, "Folsom Prison Blues," in 1968, when the economy was doing fairly well. Meanwhile, the 2008 chart-topper "Just Got Started Lovin' You" was sung by James Otto, whose wide chin and beady eyes were judged to be more mature-looking.

The theoretical framework Pettijohn uses to explain this phenomenon is called the Environmental Security Hypothesis, which he first put forth in 1999 with the University of Georgia's Abraham Tesser. Pettijohn and Tesser proposed that when people lose confidence in the economy, they tend to prefer more-mature characteristics, which seem to provide some psychological security.

Since 1999, Pettijohn's research has lent his theory some credibility. The Environmental Security Hypothesis appears to explain the variation in the typical facial arrangements of American actresses and Playboy playmates as they've changed through economic booms and busts.

To be sure, the patterns Pettijohn has stumbled upon are correlations—he never states that the economy directly causes some celebrities' popularity—but many are statistically significant. In fact, he's more confident in these findings than some previous ones. Unlike pop stars and actresses, the top country performers are a fairly uniform bunch: Most of them are thirtysomething caucasian men. Comparing amongst a like-faced group leads to cleaner, more dependable results. What's more, another study Pettijohn published last year found that older country singers are more popular during rougher economic times—another hint that people might be comforted by celebrities with mature features.

The assumption underlying Pettijohn's work is that the masses cling to reassuring, stable-looking people in turbulent times. While this explanation satisfies intuition, it's also worth considering that the people who make pop stars into pop stars—agents, talent scouts, critics—might be the ones to study and theorize about.