SALT LAKE CITY -- Ever believe a simple tweet like "I feel sad" or "I'm kinda anxious" could have a bearing on the stock market, days down the road?
It's not quite the "butterfly effect" -- the concept that something small somewhere in the world can have a significant impact over time somewhere else. Researchers at Indiana University instead call it part of the collective "Zeitgeist," or spirit of the times, and they say those sentiments on Twitter can be used to predict the oldest and most-quoted U.S. market index.
"The movements in the public mood actually predated by three to four days the up-and-down movements of the Dow Jones Industrial Average," associate professor Johan Bollen told CNBC's "Squawk on the Street" program Tuesday.
The way the correlation is determined is complicated. Bollen, whose bio includes a four-year-stint as a staff scientist at the Los Alamos National Laboratory, uses part of an algorithm that measures mood on Twitter, known as the Google-Profile of Mood States.
The algorithm takes into account levels of six moods - happiness, kindness, alertness, sureness, vitality and calmness.
The index gauging calmness, according to Bollen and his colleagues, can also forecast Dow behavior days down the road with roughly 87.5 percent accuracy.
"It all adds up and provides us with some kind of a sense of what's going on," Bollen told CNBC.
The study analyzed 9.7 million tweets from 2.7 million Twitter users over 10 months in 2008.
"We look at tweets where people say things like, I feel sad, I feel happy, I'm kinda anxious, I'm concerned about something, politics and so on. We're looking for particular markers," Bollen said.
Financial experts are raising questions about who was surveyed, which days were monitored, and whether the younger demographic on Twitter really reflects investor sentiment.
"I'm intrigued by this and I'm interested, but I don't find much validity in it," said Shane Stewart, a certified financial planner with Deseret Mutual in Salt Lake City. "The market always seems to find its real value. This is based on emotional value, which is true day to day."
Stewart warned against using the gauge as an investment tool, though it may work in short term situations. He also pointed out 2008 was the heart of the financial meltdown, when a lot of people simply felt "down" about the markets.
"I question the validity of it being an indicator of what will happen in the future," Stewart said. "Rather, I almost see it as a very short-run indicator of a very unique period in our recent history - 2008 - and so I would have to see years' worth of study on that before I put any validity in it."
Bollen is standing by his finding.
"It's perfectly possible a lot of investors are on Twitter as well and they pick up sort of the general Zeitgeist, and then that gets translated somehow, perhaps even unconsciously, into their investment strategies," Bollen said.