I'm often interrupted by thoughts, ideas and concerns when I'm working or studying. Seldomly are they related to the actual work I'm doing. I'm by no means averse to ideas and inspiration making sudden drop-ins, but I find that it severely reduces my ability to focus on the task at hand.
During my recent exams, I kept a "Think About It Later" folder in my note-taking app which I would only revisit once exams were finished. As soon as an idea, concern or otherwise diverging thought crept its way into my head, I'd make a quick note in the folder. Seemingly like magic, the thought would disappear and my focus would return. The thought just wanted to be recognised, and making a note of it did just that.
I've since learned that this is the work of the Zeigarnik effect. The Zeigarnik effect postulates that people remember unfinished or interrupted tasks better than completed tasks. What this means is that our brains tend to stay fixated with a task until it is accomplished.
Fortunately, merely making a note of something is sufficient for our brains to check it off as accomplished. That’s right: the brain doesn't distinguish between a finished task and one that is postponed by taking a note. By writing something down, we literally get it out of our heads. This is supported by the work of Dr Roy Baumeister, which has shown that:
“Uncompleted tasks take up room in the mind, which then limits clarity and focus.”
Human memory consists of two parts: short term memory and long term memory. Short term memory is limited: you can only hold between five and nine items at any given time. This is sometimes presented as 7±2 — read as ‘seven plus or minus two' and is known as Miller's Magic Number.
Each distracting thought takes up one of these limited spaces, making it increasingly difficult to allocate memory resources to the task at hand. Writing it down removes the thought from your limited short-term memory, freeing up space for the task at hand. I noticed that upon revisiting the box, the majority of the thoughts that had concerned me at the time had either sorted themselves out or shown themselves to be utter nonsense. Of the ones that could be classified as ideas, a clear separation had formed between the good ideas and bad ideas.
By preventing myself from thinking about things immediately, my thoughts had organised themselves into those worthy of my limited attention, and those not.
Consider creating a "Think About It Later" box. Stock it up throughout the day. Revisit it at the end of the day, or preferably, end of the week. Thoughts are like wine - the good ones get better with age.