Why do distractions and interruptions tend to disrupt our focus so easily?

The answer is at least partly biological. Despite modern myth, the brain isn’t a marvel of infinite capacity; we are, after all, only human, with all the limitations that implies. One limitation lies in our capacity to process what’s happening in the world around us. We’re flooded with so much sensory data at any one time that our brains have to filter out most of it to avoid overload, working with what’s left to create a structured reality that we can function within.

One result, as Winifred Gallagher points out in her intriguing book Rapt: Attention and the Focused Life, is that “when you focus, you’re spending cognitive currency that should be wisely invested, because the stakes are high.” That is, you have to make a significant mental effort to truly focus on something; hence, you’re literally “paying attention,” with attention being a limited resource in the hustle and flow of your consciousness.

This selectivity allows you to draw order out of chaos, but to do so, you have to home in on a few things at the expense of all else—which is why any interruption or distraction can be so damaging. You’re already dealing with an immense quantity of information rushing in on you, everything from the room temperature to the quality of the lighting, and your brain’s already processing that, like it or not. Adding anything more detracts from your limited ability to pay attention to other phenomena. It pulls you out of your trance focus, forcing you to lose track of what you were doing, at least temporarily. This inevitably slows you down, so you take a hit productivity-wise.

Now, it’s true that some of us can handle more distractions than others without completely losing focus, because some of us just naturally have more cognitive cash to pay attention with—just as some of us are better singers or dancers. Furthermore, with enough self-discipline, you can also build your cognitive fortune beyond its normal limitations. But no matter how much capacity for receiving and processing information you may have, you still need to focus tightly, in order to get the maximum return from anything you do—whether it’s learning, working, or dancing the tarantella.

Therefore, you must deliberately choose what you spend your attention on, and do everything possible to trim out the excess fat of distractions and interruptions—no matter how minor they may seem. Whether it’s the phone ringing or someone talking across the hall, any distraction is vying for and stealing from your limited store of attention.