The Science-Approved Reason To Steer Clear Of Selfish People Over 30

Selfish people aged 29 and under are all fine though. Phew.

Here's a nightmare scenario for you.

Imagine waking up to discover the human being in bed next to you has cocoonned himself in your whole duvet. After lying there for a few hours, on the brink of hypothermia, you get up. Only to realise that the aforementioned human being has finished all the milk in the fridge. As you sip your slightly-bitter black coffee, you hear the bathroom door bang and the shower begin to run. Half an hour later it stops, and as you reach for your towel, it dawns on you: the hot water only lasts for 25 minutes.

We all have those people in our lives. The selfish ones. The ones who put themselves first, and don't see a problem with it. If MSN messenger was still a thing, their usernames would feature quotes from Darwin about 'survival of the fittest', and how 'it's a dog eat dog world out there'.

But instead of sticking around and trying to convince yourself that they'll 'grow out of it' over time, a new study involving - wait for it - mongooses, has revealed that selfish people are probably going to be selfish people forever.

During their study of the mongooses (mongeese?!), researchers looked into how much time the male ones spent selfishly guarding their mates from any prospective competition - and how much time they spent raising their offspring. And they discovered that the selfless mongooses who spent time with their kids were likely to behave like that over the course of their entire lives - while a mongoose who was preoccupied with keeping his female mongoose all to himself was unlikely to change, too.

And before you object to the fact that this study was carried out on large meerkats rather than, y'know, humans, it turns out that the results are more applicable to us than we thought. Especially if the selfish person in your life happens to be over the age of 30.

Yep, while we can attempt to teach other people to be more selfless through their teens and early 20s, once they reach their fourth decade, they'll hit what is called a 'personal stability plateau' - when their character becomes more fixed.

Meaning that if you want to find somebody who'll share the duvet with you, it's best to find them before they turn 29.

Somebody better tell Kim Kardashian. Stat.