(FORTUNE Magazine) – Here's another way to forecast business cycles: Listen to pop music's lyrics. Harold Zullow, a research fellow in social psychiatry at Columbia University, says the mood of songs that make it to the Top 40 foreshadows recessions and recoveries. Zullow argues that these forward indicators appear to happen a full year or more before the GDP goes through its changes and many months before shifts in the mood of America show up on consumer optimism indexes. To reach his conclusions, Zullow, 30, rated the lyrics of the Top 40 songs each year since 1955, based on Billboard's listings, for what he calls ''pessimistic explanatory style'' and ''rumination about bad events.'' In general, he found songs got downbeat at least a year before each recession and positively sanguine about the same time before a boom. Remember feeling good to the beat of Sam Cooke's 1957 classic ''You Send Me''? Zullow says the words were a precursor to the GDP growth that arrived in mid-1958 and ran through mid-1960. (See chart for other examples.) Zullow has not completed his analysis of where the economy is headed in 1993. But a quick review of hit songs suggests it's heading back south. % What's next for Zullow? As you might expect, he's at work to find a corollary between hit songs and stock market prices.

CHART: NOT AVAILABLE CREDIT: FORTUNE CHART CAPTION: HOW POP SONGS HAVE FORECAST UPS AND DOWNS IN THE GDP