During single-minded work time, people are ideally in a state that psychologists call flow. Flow is a condition of deep, nearly meditative involvement. In this state, there is a gentle sense of euphoria, and one is largely unaware of the passage of time: “I began to work. I looked up and three hours had passed.” There is no consciousness of effort; the work just seems to, well, flow. You’ve been in this state often, so we don’t have to describe it to you.
Not all work roles require that you attain a state of flow in order to be productive, but for anyone involved in engineering, design, development, writing, or like tasks, flow is a must. These are high-momentum tasks. It’s only when you’re in flow that the work goes well.
Unfortunately, you can’t turn on flow like a switch. It takes a slow descent into the subject, requiring fifteen minutes or more of concentration before the state is locked in. During this immersion period, you are particularly sensitive to noise and interruption. A disruptive environment can make it difficult or impossible to attain flow.
Once locked in, the state can be broken by an interruption that is focused on you (your phone, for instance) or by insistent noise (“Attention! Paging Paul Portulaca. Will Paul Portulaca please call extension…”). Each time you’re interrupted, you require an additional immersion period to get back into flow. During this immersion, you’re not really doing work.
-Tom DeMarco & Timothy Lister, “Brain Time Versus Body Time”, Peopleware