Laminated cards were made up announcing “quiet time” and attached to cubicles. But within a few weeks the workers found the system too restrictive, and the cards seemed like something from grade school.

The cards came down, and some employees started to use e-mail messages, though judiciously and with more awareness of their habits, while others continued the stricter regimen, said Brad Beavers, the Austin site manager.

In a survey, nearly three-quarters of participants said the quiet time routine should be extended to the rest of the company.

“It’s huge. We were expecting less,” said Nathan Zeldes, an Intel engineer who led the experiments and who for a decade has been studying the impact of technology on productivity. “When people are uninterrupted, they can sit back and design chips and really think.”

In the other experiment, called “zero e-mail Fridays,” the goal was to encourage employees to favor face-to-face communication. Mr. Beavers said employees liked the idea in theory, but they continued to send e-mail messages, finding them essential.

Just 30 percent of employees endorsed the program, but 60 percent recommended it for wider use at Intel, with modifications.

“We’re trying to address the problem that people get so addicted to e-mail that they will send an e-mail across an aisle, across a partition, and that’s not a good thing,” he said.