People like procrastinating. Or at least, they keep doing it despite their protestations. It’s very common to see Facebook posts or tweets where someone reveals that they shouldn’t be on Facebook or Twitter because they have important work to do, but are procrastinating. So people procrastinate by going online and pointing out they’re procrastinating. That’s some advanced-level time-wasting there.

But, and most people will be familiar with this, once the time available to do the specific task being avoided starts to run out, procrastination reduces. The most common distraction from the task is the occasional panicked glance at the clock, occasionally with an expletive-ridden rant that it can’t possibly be that late already. And so we see the power of a deadline.

In the historical sense, a deadline refers to the boundary around a prison which, if prisoners crossed it, they’d be shot by the guards. This definition isn’t very applicable these days unless you work for an extremely strict boss. Instead, the term is now used to mostly to refer to “the time by which something must be completed”. With this definition, deadlines are everywhere in the modern world.

You have deadline for completing the journey to work. Your boss assigns you many jobs and tasks that have to be completed in a certain time, racking up more deadlines (and even more on top if he’s the sort who’ll shoot you for wandering off too far). You arrange to meet people and have to get ready by a certain time, that’s another deadline. You receive a flirty text from someone you like and have to reply before a certain time to not make it seem like you’re uninterested, but not too soon to seem desperate. And there are more widely-applicable deadlines. For example, at time of writing, today is the voter registration deadline for the UK General Election.

The consequences of missing a deadline vary substantially, and people can respond to them very differently. Douglas Adams famously said he loved deadlines because of “the wooshing noise they make as they go by”. But the general pattern is that, as people approach a deadline, they typically become more motivated and work harder at the task in hand, and performance can even improve.

This hasn’t been overlooked by psychologists, who have done a fair amount of research into deadlines (all of which will have probably been completed to a deadline set by funding restrictions, for added irony). The improved performance as a deadline looms can be explained to some extent by the Yerkes-Dodson law. This states that a person’s performance increases as their arousal increases, but only up to a point, after which performance starts to suffer as the person becomes overwhelmed or distracted.

“Arousal” can be taken here to mean “stress”, or the general nervousness and tension resulting from a combined awareness of the potential consequences of failing to complete an important task and the limited time remaining to complete it. The human brain may like to procrastinate, but it likes to avoid unpleasant occurrences more, so it tends to adopt a more “playtime’s over!” approach when a deadline is imminent.

Obviously this stress = better performance only works up to a point, after which stress can have some very unpleasant consequences.

Why does this keep happening though? People deal with countless deadlines all the time, but they repeatedly end up panicked as the crucial time approaches and they haven’t done the important thing they swore to themselves they would have done by now as they had loads of time. You probably know someone who is perpetually late for meetings and assignments, who can’t seem to grasp the most basic schedule and stick to it. If you don’t know anyone like this, it’s probably you. Your friends find you incredibly annoying, by the way.

But in defence of the disorganised, there seems to be some deep-seated psychological tendency to do this, known as the planning fallacy. This occurs because the human brain has a bizarrely optimistic slant when it comes to estimating how long things will take to do, and invariably underestimates. As well as this, it has a tendency to attribute previous failures to meet a deadline to external causes, e.g. “I know I turned up at the funeral with a Get Well Soon card, but that’s because the World Cup was on”. These optimistic assumptions tend to dominate planning and performance until the deadline encroaches, and the actual reality of the situation is harder or impossible to ignore.

But this applies to personal, tangible deadlines that clearly affect you. What about things like the voter registration? Given the vastly complicated way politics works, it’s harder to associate registering to vote with any direct tangible benefits or consequences outside of the more cerebral appreciation of democracy (well, hopefully). Some people are passionate about voting, no question, but they’d surely already be registered. So what is it about the deadline that would make people who don’t care enough to have registered already suddenly want to?

There are numerous possible variables, but one may be the impact of scarcity. There’s a lot of interest in the fact that people invariably want things more if they’re scarce (e.g. precious metals, limited editions, exotic pets, a decent quality Hollywood sequel etc.) When the voter registration deadline is looming, the option of registering is about to be taken away. When it’s available, that’s fine, but the possibility of it being lost may motivate many to register regardless of their voting intentions, just because they can say they can. There may also be a feeling of superiority over those who didn’t register as well, enhancing one’s sense of social status.

Overall, deadlines may be unpleasant and annoying, but they do seem to make sure things get done. Not necessarily done well, but done regardless. And, like with politics, sometimes that’s the best we can hope for.

Dean Burnett started writing this post less than 2 hours before it was uploaded, so had a self-imposed deadline to test the claims made here. He’s on Twitter, @garwboy