“From an observer’s perspective, you’re watching a person [and] they’re typing in a Word document. And then, for no apparent reason, they suddenly stop what they’re doing and they shift and look at e-mail or check Facebook. These kinds of self-interruptions happen almost as frequently as people are interrupted from external sources,” Mark said. “So we find that when external interruptions are pretty high in any particular hour, then even if the level of external interruptions wanes [in the next hour], then people self-interrupt.”
