The degree of the economic downturn of the last year is surprising even to Warren Buffett, often called the world’s best investor.

“It has fallen off a cliff,” said Buffett, chairman of Berkshire Hathaway, in an interview that aired on CNBC’s Squawk Box early Monday. “Not only has the economy slowed down, people have changed their behavior like nothing I have ever seen.”

Buffett said that so far, the message from the government has been “muddled,” but that the government will play a big role in turning the economy around, though he said it won’t happen fast. “You can’t turn around on a dime,” Buffett said. He said people’s changed habits have been good news for companies like Wal-Mart, and bad new for luxury goods, like high-end jewelry. — Lavonne Kuykendall