Many years ago now, I went through a bout of clinical depression. That sickness killed my concentration span. I could not read more than one or two pages of any kind of book before feeling sleepy. As soon as I put the book down, I was alert again.
My concentration span was pathetic and not improving.
In October 2012, I watched a badly shot video of Joe Kraus from Google Ventures who introduced the idea of Gap Time and "Slow Tech" to me.
The basis of the idea is that we live in a world of constant distraction and that paired with our evolutionary tendency to respond to stimulus has resulted in us heightening that skill and reducing our concentration spans. Technology in particular has been a culprit in this decline.
His fix for this was to suggest that we take time to not be distracted. Down time for your brain. That meant not picking up my phone when I was sitting waiting for someone at a cafe; not turning on music or a podcast in all my down time; and simply letting my brain spend time background processing.
Since taking on board this approach and spending a lot of time not doing anything with my brain, my concentration span is quite amazing. After 6 months, I could read up to 200 pages without feeling drained or distracted. After 18 months, I can read a book cover to cover without pausing... at least when I have the time to do so.
For me, that is a quantification of how my mind has improved by taking the time to let it rest. Not watching TV or Facebooking but actually taking time to do nothing. Distraction is not a good thing, at least not at the rates we allow it in our lives.
Take some time to lie on the couch and stare at the ceiling or drive to work without the radio on. It will change you.