This optimism was most evident among new employees, the report found, and it was bound to show up on days when Google stock had climbed.

This discovery largely jibes with what experts have found about the entrepreneurial mindset. If you take a job where much of the reward will come from the appreciation of company stock, you tend to see the silver lining within the cloud. (What is striking is that this bias was detected at Google during its greatest period of success. The stock more than tripled in the two-and-a-half-year period being studied, yet it was still possible to be too bullish about the company.)

Beyond its findings, the report is fascinating for its inadvertent peeks into the secretive world of Googleland.

One learns, for example, that the researchers could determine “physical proximity” by using “data on the precise latitude and longitude of employees’ offices”  the better to find the closest burrito stand using Google Earth, I guess.

Also, the authors report that “employees moved offices extremely frequently” during the time they were studying the company, about once every 90 days. “You walk into their offices and no one packs from their moves,” Mr. Zitzewitz said, a sign, he said, that Google was acting on the kind of insights the report described and was putting the right people next to one another.

A question never addressed in the report is what would seemingly be most interesting to an outsider: Do prediction markets work? Unlike surveys, the markets rely on something, I think the technical term is ... oh, yeah, greed, to get their results.

Ask me who I think will win a baseball game, an election and an Oscar, and I can try to be objective, but I can’t help being influenced by who I would like to see win. (The Yankees, Fred Thompson, Pee-wee Herman; or is it the Yankees, Pee-wee Herman, Fred Thompson?) Put $5 on it, however, and suddenly I am willing to use all the information I have at my disposal to come up with the best answer.