Five minutes doesn't seem like enough time to accomplish anything of real importance. That's why, when we have these little scraps of time to spare, we often just throw them away on social media or cat videos.

But according to Instagram co-founder Kevin Systrom, five minutes is actually all the time you need to conquer your fears and get started on that important project or big dream you've been persistently putting off.

When Axios's Mike Allen asked the billionaire entrepreneur for his favorite life hack, Systrom didn't wax poetic about some elaborate productivity system or extol the life-changing nature of his morning routine. Instead, he gave a dead-simple answer anyone who has ever struggled with procrastination can put to use today:

"If you don't want to do something, make a deal with yourself to do at least five minutes of it. After five minutes, you'll end up doing the whole thing."

Why five minutes is enough to beat procrastination

It sounds like too simple a cure to be effective, but according to science, Systrom is onto something for a couple of reasons.

First, we often procrastinate out of fear of failure -- a project seems just too big and scary to actually ever accomplish, so we end up throwing up our hands and conceding defeat before we even start. Breaking down your biggest goals into baby steps helps take away that terror. Writing a novel might sound beyond you, but no one can stress about five minutes of free writing.

So a tiny five-minute commitment gets us over the hurdle of our fear. It also shows us that the reality of the work is almost certainly less terrifying than we imagined before we got started. As writer Eliezer Yudkowsky points out, "On a moment-to-moment basis, being in the middle of doing the work is usually less painful than being in the middle of procrastinating." (Hat tip to Jory MacKay for the quote.)

Finally, getting started on something, even just briefly, activates a psychological phenomenon known as the Zeigarnik effect, in which it's much harder to get unfinished tasks out of your brain than completed ones. It's why that half-done chore keeps popping into your mind, and also why once you write down tasks on a to-do list, your mind quiets and you often forget about the list. The act of writing down a plan quiets the Zeigarnik effect.

Systrom's five-minute hack uses the Zeigarnik effect to your advantage. By starting the task, you're just begging your brain to continue nagging you to complete it, making it more likely you'll finally finish what you've started.

For all these reasons, Systrom's hack manages to be incredibly powerful despite its simplicity. So next time you have five minutes to spare, rather than just opening up Facebook or browsing the headlines, why not start something you've been putting off?

The worst that can happen is you'll miss out on five minutes of online nonsense. The best that can happen? You'll discover the best little procrastination cure going.