Being bad-tempered and pessimistic helps you to earn more, live longer and enjoy a healthier marriage. It���s almost enough to put a smile on the dourest of faces.

On stage he’s a loveable, floppy-haired prince charming. Off camera – well let’s just say he needs a lot of personal space. He hates being a celebrity. He resents being an actor. To his ex-girlfriend Elizabeth Hurley's friends he was apparently known as ‘Grumpelstiltskin’.

Hugh Grant may be famed for being moody and a little challenging to work with. But could a grumpy attitude be the secret to his success?

The pressure to be positive has never been greater. Cultural forces have whipped up a frenzied pursuit of happiness, spawning billion-dollar book sales, a cottage industry in self-help and plastering inspirational quotes all over the internet.

Now you can hire a happiness expert, undertake training in ‘mindfulness’, or seek inner satisfaction via an app. The US army currently trains its soldiers – over a million people – in positive psychology and optimism is taught in UK schools. Meanwhile the ‘happiness index’ has become an indicator of national wellbeing to rival GDP.

The truth is, pondering the worst has some clear advantages. Cranks may be superior negotiators, more discerning decision-makers and cut their risk of having a heart attack. Cynics can expect more stable marriages, higher earnings and longer lives – though, of course, they’ll anticipate the opposite.

Good moods on the other hand come with substantial risks – sapping your drive, dimming attention to detail and making you simultaneously gullible and selfish. Positivity is also known to encourage binge drinking, overeating and unsafe sex.

At the centre of it all is the notion our feelings are adaptive: anger, sadness and pessimism aren’t divine cruelty or sheer random bad luck – they evolved to serve useful functions and help us thrive.  

Take anger. From Newton’s obsessive grudges to Beethoven’s tantrums – which sometimes came to blows – it seems as though visionary geniuses often come with extremely short tempers. There are plenty of examples to be found in Silicon Valley. Amazon founder Jeff Bezos is famed for his angry outbursts and insults (such as “I’m sorry, did I take my stupid pills today?”) yet they haven’t stopped him building a $300 billion company.

For years, the link remained a mystery. Then in 2009 Matthijs Baas from the University of Amsterdam decided to investigate. He recruited a group of willing students and set to work making them angry in the name of science. Half the students were asked to recall something which had irritated them and write a short essay about it. “This made them a bit angrier, though they weren’t quite driven to full-blown fits of rage,” he says. The other half of the group were made to feel sad.

Next the two teams were pitched against each other in a game designed to test their creativity. They had 16 minutes to think of as many ways as possible to improve education at the psychology department. As Baas expected, the angry team produced more ideas – at least to begin with. Their contributions were also more original, repeated by less than 1% of the study’s participants.

Anger really prepares the body to mobilise resources

Crucially, angry volunteers were better at moments of haphazard innovation, or so-called “unstructured” thinking. Let’s say you’re challenged to think about possible uses for a brick. While a systematic thinker might suggest ten different kinds of building, it takes a less structured approach to invent a new use altogether, such as turning it into a weapon.

In essence, creativity is down to how easily your mind is diverted from one thought path and onto another. In a situation requiring fight or flight, it’s easy to see how turning into a literal “mad genius” could be life-saving.

“Anger really prepares the body to mobilise resources – it tells you that the situation you’re in is bad and gives you an energetic boost to get you out of it,” says Baas.

To understand how this works, first we need to get to grips with what’s going on in the brain. Like most emotions, anger begins in the amygdala, an almond-shaped structure responsible for detecting threats to our well-being. It’s extremely efficient – raising the alarm long before the peril enters your conscious awareness. 

Then it’s up to chemical signals in the brain to get you riled up. As the brain is flooded with adrenaline it initiates a burst of impassioned, energetic fury which lasts for several minutes. Breathing and heart rate accelerate and blood pressure skyrockets. Blood rushes into the extremities, leading to the distinctive red face and throbbing forehead veins people get when they’re annoyed.

Though it’s thought to have evolved primarily to prepare the body for physical aggression, this physiological response is known to have other benefits, boosting motivation and giving people the gall to take mental risks.

All these physiological changes are extremely helpful – as long as you get a chance to vent your anger by wrestling a lion or screaming at co-workers. Sure, you might alienate a few people, but afterwards your blood pressure should go back to normal. Avoiding grumpiness has more serious consequences.

The notion that repressed feelings can be bad for your health is ancient. The Greek philosopher Aristotle was a firm believer in catharsis (he invented the modern meaning of the word); viewing tragic plays, he conjectured, allowed punters to experience anger, sadness and guilt in a controlled environment. By getting it all out in the open, they could purge themselves of these feelings all in one go.

His philosophy was later adopted by Sigmund Freud, who instead championed the cathartic benefits of the therapist’s couch.

Then in 2010 a team of scientists decided to take a look. They surveyed a group of 644 patients with coronary artery disease to determine their levels of anger, suppressed anger and tendency to experience distress, and followed them for between five and ten years to see what happened next.

Over the course of the study, 20% experienced a major cardiac event and 9% percent died. Initially it looked like both anger and suppressed anger increased the likelihood of having a heart attack. But after controlling for other factors, the researchers realised anger had no impact – while suppressing it increased the chances of having a heart attack by nearly three-fold.

It’s still not known exactly why this occurs, but other studies have shown that suppressing anger can lead to chronic high blood pressure.

And not all benefits are physical: anger can help with negotiating, too. A major flashpoint for aggression is the discovery that someone does not value your interests highly enough. It involves inflicting costs – the threat of physical violence – and withdrawing benefits – loyalty, friendship, or money – to help them see their mistake.

Support for this theory comes from the faces we pull when angry. Research suggests they aren’t arbitrary movements at all, but specifically aimed at increasing our physical strength in the eyes of our opponent. Get it right and aggression can help you advance your interests and increase your status – it’s just an ancient way of bargaining.

In fact, scientists are increasingly recognising that grumpiness may be beneficial to the full range of social skills – improving language skills, memory and making us more persuasive.

“Negative moods indicate we’re in a new and challenging situation and call for a more attentive, detailed and observant thinking style,” says Joseph Forgas, who has been studying how emotions affect our behaviour for nearly four decades. In line with this, research has also found that feeling slightly down enhances our awareness of social cues. Intriguingly, it also encourages people to act in a more – not less – fair way towards others.

Harsh, but fair

Though happiness is often thought of as intrinsically virtuous, the emotion brings no such benefits. In one study, a group of volunteers was made to feel disgusted, sad, angry, fearful, happy, surprised or neutral and invited to play the “ultimatum game”.

In the game, the first player is given some money and asked how they’d like to divide it between themselves and another player. Then the second player gets to decide whether or not to accept. If they agree, the money is split how the first player proposed. If not, neither player gets any money.

Happier participants keep more of the prize for themselves, while those in a sad mood are significantly less selfish

The ultimatum game is often used as a test of our sense of fairness by showing whether you expect to get a 50-50 share or whether you are happy for each person to be in it for themselves. Interestingly, all negative emotions led to more rejections by the second player, which might suggest that these feelings enhance our sense of fairness and the need for everyone to be treated equally.

Reversing the set-up reveals this is not just a case of sour grapes, either. The “dictator game” has exactly the same rules except this time the second player has no say whatsoever – they simply receive whatever the first player decides not to keep. It turns out that happier participants keep more of the prize for themselves, while those in a sad mood are significantly less selfish.

“People who are feeling slightly down pay better attention to external social norms and expectations, and so they act in a fairer and just way towards others,” says Forgas.

In some situations, happiness carries far more serious risks. It’s associated with the cuddle hormone, oxytocin, which a handful of studies have shown reduces our ability to identify threats. In prehistoric times, happiness would have left our ancestors vulnerable to predators. In modern life, it prevents us paying due attention to dangers such as binge drinking, overeating and unsafe sex.

“Happiness functions like a shorthand signal that we’re safe and it’s not necessary to pay too much attention to the environment,” he says. Those in a continuous happy haze may miss important cues. Instead, they may be over-reliant on existing knowledge – leaving them prone to serious errors of judgement.

Those in a good mood were less able to think sceptically and were significantly more gullible

In one study, Forgas and colleagues from the University of New South Wales, Australia, put volunteers in either a happy or sad mood by screening films in the laboratory. Then he asked them to judge the truth of urban myths, such as that power lines cause leukaemia or the CIA murdered President Kennedy. Those in a good mood were less able to think sceptically and were significantly more gullible.

Next Forgas used a first-person shooter game to test if good moods might also lead people to rely on stereotyping. As he predicted, those in a good mood were more likely to aim at targets wearing turbans.

Of all the positive emotions, optimism about the future may have the most ironic effects. Like happiness, positive fantasies about the future can be profoundly de-motivating. “People feel accomplished, they relax, and they do not invest the necessary effort to actually realise these positive fantasies and daydreams,” says Gabriele Oettingen from New York University.

Graduates who fantasise about success at work end up earning less, for instance. Patients who daydream about getting better make a slower recovery. In numerous studies, Oettingen has shown that the more wishful your thinking, the less likely any of it is to come true. “People say ‘dream it and you will get it’ – but that’s problematic,” she says. Optimistic thoughts may also put the obese off losing weight and make smokers less likely to plan to quit.

Defensive pessimism

Perhaps most worryingly, Oettingen believes the risks may operate on a societal level, too. When she compared articles in the newspaper USA Today with economic performance a week or a month later, she found that the more optimistic the content, the more performance declined. Next she looked at presidential inaugural addresses – and found that more positive speeches predicted a lower employment rate and GDP in during their time in office.

Combine these unnerving findings with optimism bias – the tendency to believe you’re less at risk of things going wrong than other people – and you’re asking for trouble. Instead, you might want to consider throwing away your rose-tinted spectacles and adopting a glass half-empty outlook. “Defensive pessimism” involves employing Murphy’s Law, the cosmic inevitability that whatever can go wrong, will go wrong. By anticipating the worst, you can be prepared when it actually happens.

It works like this. Let’s say you’re giving a talk at work. All you have to do is think of the worst possible outcomes – tripping up on your way to the stage, losing the memory stick which contains your slides, computer difficulties, awkward questions (truly accomplished pessimists will be able to think of many, many more) – and hold them in your mind. Next you need to think of some solutions.

Psychologist Julie Norem from Wellesley College, Massachusetts, is an expert pessimist. “I’m a little clumsy, especially when I’m anxious, so I make sure to wear low-heeled shoes. I get there early to scope out the stage and make sure that there aren’t cords or other things to trip over. I typically have several backups for my slides: I can give the talk without them if necessary, I email a copy to the organizers, carry a copy on a flash drive, and bring my own laptop to use…” she says. Only the paranoid survive, as they say.

So the next time someone tells you to “cheer up” – why not tell them how you’re improving your sense of fairness, reducing unemployment and saving the world economy? You’ll be having the last laugh – even if it is a world-weary, cynical snort.

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