WASHINGTON – Something was amiss in the Oval Office. Ben Bernanke, President Bush’s new chief economic adviser, had arrived to brief the president last summer wearing a charcoal suit, black shoes, and – gasp – tan socks.

The socks prompted Mr. Bush to reach out and tug at Mr. Bernanke’s trouser leg, playfully chiding him that he was not holding up the White House’s sartorial standards. But Bernanke recovered quickly from his wardrobe malfunction. At another Oval Office gathering the next day, the president cracked up when a group of administration officials including Vice President Cheney showed up wearing tan socks that Mr. Bernanke had provided, a participant at both meetings recalled.

The socks episode might have been nothing more than a brief chuckle. But by helping to forge a bond between Mr. Bernanke and Mr. Bush, it might also have been a fashion faux pas that changed history. Yesterday, the president nominated the 51-year-old economist to replace Federal Reserve Board Chairman Alan Greenspan, who is planning to step down January 31 from the job he has held for more than 18 years.

Mr. Bernanke’s lack of pretension and sense of whimsy are among his most striking characteristics, according to many of his friends and colleagues. Those traits, they said, will serve him well if he is confirmed by the Senate for the Fed chief’s job because the chairman cannot decide monetary policy alone; by tradition, he must mobilize a strong majority among the seven-member board and the 12-member Federal Open Market Committee, which have responsibility for setting key interest rates. That task requires not only intellectual firepower but also interpersonal skills.

The son of a pharmacist and schoolteacher who grew up in Dillon, S.C., Mr. Bernanke trained at Harvard University and the Massachusetts Institute of

Technology. He later thrived as a professor – first at Stanford, then Princeton – both as a prolific scholar and as a teacher who was popular with students for his ability to demystify complex economic subjects. He offered keen insight into his background and personality in a speech early this year about how he had gone from the world of academe to policymaking.

“I always thought I would be an academic lifer,” he said, recalling that before being appointed to the Fed board in August 2002, he had gone straight from graduate school to faculty posts. “The sum of my political experience consisted of two terms on the local school board, six grueling years during which my fellow board members and I were trashed alternately by angry parents and angry taxpayers.”

As for his administrative experience, he cited his seven years as department chair, “where I had responsibility for major policy decisions such as whether to serve bagels or doughnuts at the department coffee hour.”