Nervous mannerisms

Biting your nails in the UB

During exam periods, students chew hundreds of pens to pieces, bite their nails to the quick, and lock and unlock their phones until the batteries run out. What causes this behaviour?
By Nanette Vellekoop / Gifs by Marre Meijerink / Translation by Sarah van Steenderen

Nail biting

The UB is filled to the brim. Sighing, students pore over their books. In front of you, a guy keeps taking off his ring. And putting it back on. And taking it off. And putting it back on. Next to you, someone keeps scooting their chair back and forth. A girl incessantly twirls her hair around her finger.

None of these things are necessarily all that annoying. Truly annoying is that guy on your other side, who won’t stop clicking his pen. Or the person who keeps humming ‘All I Want for Christmas’.

Most people have tics like, although ‘technically they’re not tics’, behavioural scientist Bauke Buwalda says. ‘People who suffer from Tourette syndrome have tics. Bouncing your leg or drumming your fingers on the table are what we call mannerisms.’

And these mannerisms are annoying, because they disturb other people. But nail biting, randomly unlocking and locking your phone, or scratching your head are also mannerisms.


International relations student Chinouk (18) sometimes suffers from them. ‘I don’t even notice when I’m biting my nails. I’ll suddenly see that my nails are really short, only realising in hindsight that it’s because I’ve been really busy. I don’t actually want to bite my nails, but I just need to do something with my hands.

Clicking your pen

Chinouk is currently trying to grow her nails. ‘I’ll make sure I have something else to occupy my hands, such as a hair elastic or a pen. It’s still a tic, but at least not one that’s as gross.’

There is a reason people do this. Mannerisms are often related to stress. It’s the body’s attempt to diminish tension. Almost everyone who has ever been stressed or nervous has exhibited these kinds of mannerisms.


‘It’s not necessarily a bad thing’, says Buwalda. ‘We are confronted with different kinds of situations every day, and our bodies need to some way to deal with that. Stress is one possible reaction, and repeated behaviour is an expression of that stress.’

The function of the behaviour varies, says Buwalda. ‘It can serve as a form of de-arousal. This happens after a stressful moment. This releases opiate-like endorphins that calm you down. It allows you to focus on something else, such as your hair, hands, or nails. We also see it in animals who, after a stressful moment, suddenly start washing themselves more.’

Whenever Buwalda feels stressed, he starts snacking. It is another tried and tested way of releasing tension, he says. Recent research showed that rats who ate sweet and fatty foods had a diminished stress response, as opposed to rats raised mainly on vegetables.

Smokers, for example, often start smoking more when they find themselves in stressful situations. ‘When I’m studying, I do find myself taking more smoke breaks’, says law student Frank (24). ‘Part of that is procrastination, but I also smoke more when I don’t have anything to do.’


Head scratching

So while mannerisms are common and perfectly innocent, they can evolve into more dangerous behaviour: a compulsive disorder. This happens when mannerisms stop being subconscious. ‘That’s when people actively start trying to control a situation to feel less stress’, says Menno Oosterhoff, who wrote a book about compulsive disorders. ‘Most people, regardless of the situation, have their own little mannerisms, and stress can make those worse. Stress makes most things worse. Your brain is under pressure, and that can make people do strange things.’

When social works student Nant (20) is under pressure, her head starts itching. ‘I notice that I’m scratching my head, although it’s not a conscious action’, she says. ‘It gets worse right before I have an exam, but other than that, I don’t really suffer from it. My parents think it’s really annoying, so when I’m studying at home I do it secretly. My right leg also starts bouncing when I’m stressed.’

Other people do actually display tics when they are stressed. They keep sniffing, blinking their eyes, or humming. ‘That occurs mainly among school-aged children’, says UMCG psychiatrist Anne van Lammeren. ‘Between five and nine percent of children suffer from this.’

Tics usually disappear on their own, or people suffering from them learn to suppress them. Right until the moment you get stressed out of your mind right before an exam.


It’s important to distinguish between short-term and long-term stress. In cases of acute stress, during a near-accident for example, adrenaline is released and your blood vessels expand to get blood to the muscles faster. It’s the body preparing itself for action. This system is functional, and short-term. Long-term stress however, happens when you experience stress about something that could last a long time, or when you keep thinking about stress. This chronic stress is the kind that can actually make you ill. With mannerisms, this is expressed in how severe they are.

Bouncing your leg


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