You know that thing where you get up to go to another room to get something, and then when you get there, you forgot why you went there? Psychologists call it the “doorway effect” (as in you forget stuff when you walk through a doorway). It’s totally a known thing that happens with human memory (this BBC article explain why).
I have the modern day equivalent of that: I call it the browser tab effect. I’ll be working on something in say, a Word document or a spreadsheet and I’ll think “I need to look up X”. So I flip to another application – often my internet browser, to look up X and then… what was I looking for? Often this compounded by the fact that when I flip over to my Internet browser, I see the last tab I was on and it reminds of the incomplete task I had related to that tab because I went off to some other application on my computer to do some other thing.
It also doesn’t help that my browser usually looks something like this: