'Mental flexibility' is science's best predictor of lasting willpower. Here's how to improve yours

When the road gets tough, do you dig deep, push forward and refuse to back down? If so, you likely believe in the power of mental toughness – the ability to overcome obstacles with sheer focus and will.

The idea is simple enough: by strengthening your mind, you can bulldoze through any barrier standing between you and your goals, whether it's crushing a personal best at the gym or landing that big promotion.

Mental toughness is about believing in your ability to persevere, no matter what stands in your way.

Sounds logical, even admirable, right? But there's a huge hidden catch: relying solely on mental toughness might not serve you well in the long run.

Take marathon running as an example. If someone adopted a mindset of mental toughness, they could end up powering through their pain – but only once.

“They might finish their race through this idea of mental toughness,” says Dr Josephine Perry, a chartered sports and exercise psychologist. “But they might never be able to run another one, because they’ve hurt themselves so much along the way.

"They’ve just totally fallen out of love with the process, because it was all about pain and discomfort.”

You’ll be pleased to hear there’s another way. It’s called a ‘flexible mindset’.

You’ll certainly still encounter setbacks, but instead of blindly pushing through, you might rethink your training plan, while still keeping your goals in mind. It's about being strategic, stepping back and considering the long-term impact of your actions.

“Flexibility is about winning the war and being more clever with how you do things… rather than just getting your head down and throwing yourself into every battle that comes along,” says Perry.

The benefits of mental flexibility

Mental flexibility isn't just for athletes, though. Research shows that those who develop it reap significant mental and professional benefits.

In one large analysis of multiple studies using a standard mental flexibility questionnaire, higher flexibility scores were linked to better overall mental health.

One paper, looking at call centre workers, found that those who scored higher levels of mental flexibility performed better at their jobs, adapting more effectively to challenges.

Another paper, looking at people with chronic pain, found that those who had higher mental flexibility scores had more ‘up-time’ throughout the day, allowing them to stay active and engaged for longer.

The list goes on: according to one study, US military veterans who were more mentally flexible exhibited fewer signs of post-traumatic stress disorder (PTSD).

Another paper, looking at wellbeing in the UK, found that people who were more mentally flexible were less likely to experience anxiety and depression during the COVID-19 pandemic.

Even more compelling, some psychologists contend that mental flexibility not only trumps sheer toughness, it may also outperform what we call positive thinking.

In this clinical sense, positive thinking involves maintaining an unwavering, optimistic outlook, even when it drifts away from reality.

“People are still talking about being optimistic, [having] gratitude, being kind, being generous,” says Dr Todd Kashdan, a professor of psychology and founder of the Well-Being Lab at George Mason University, in the US.

“All those things are good, but certain situations require a little bit more darkness, a little bit more negativity.”

What mental flexibility actually means

So, what exactly is mental flexibility, also known as psychological flexibility? One definition Kashdan works with is a willingness to match your behaviour to whatever the situation demands.

Say, for example, you’re trying to persuade your colleagues to get behind your idea before a big meeting, or convince your surly teenager to get an early night for once.

Someone who is mentally flexible will be able to change their approach in response to the feedback they’re getting.

“[They might think] ‘Okay, humour isn’t working here… Let me try listening and asking open-ended questions’,” says Kashdan. “You’re able to pivot much easier when you have other strategies that are easy to deploy and access.”

The idea of mental flexibility draws on the principles of Acceptance and Commitment Therapy (ACT), an approach to psychotherapy that focuses on – as the name suggests – accepting your feelings as they are, including any that are painful or difficult, and committing to making meaningful changes in your life.

Acceptance is a crucial part of mental flexibility because, however much we might try, we can’t avoid negative feelings.

“If you want to excel in fitness, you’re going to have a lot of negative emotions as you grunt through days where you don’t want to wake up,” says Kashdan. “If you want to be a master in psychology or business or politics, that level of learning requires a lot of confusion, difficulty and self-doubt.”

While accepting those negative thoughts might seem counterproductive, research shows that the alternative – trying to suppress them – simply doesn’t work.

“One of my athletes described it as ‘whack-a-mole’ – that as soon as you try and block out one negative thought, another one pops up,” says Perry. “And when you block out that one, another shows up.”

The idea is that, once you stop wasting time struggling against your negative feelings, you’ll be able to see your inner monologue as simply a string of thoughts or prompts, rather than facts. From there, you can begin reframing the thoughts that don’t serve your goals.

“We’re not lying to ourselves,” says Perry. You wouldn’t tell yourself that you’re acing a job interview that doesn’t seem to be going very well, for example.

You might reframe it, however, as a good opportunity to practise your interview skills, even if you don’t end up getting the job.

This framing can help you deal with any difficult situations at hand and keep you moving towards your ultimate goal, even when reality veers off course.

Training your brain begins with mindfulness

Starting to train your own brain to be more flexible is relatively simple, on paper. You just need to start noticing what thoughts are running through your mind.

If this sounds a lot like mindfulness, there’s a good reason for that – Perry says that mindfulness work is often the starting point for athletes wanting to improve their mental flexibility.

But – thankfully – it absolutely doesn’t have to involve sitting cross-legged for half an hour as your thoughts drift off on imaginary clouds.

In her work with athletes, Perry says she’s found that activities, such as swimming, yoga or even playing with jigsaws, serve as a good environment to start practising this vital skill.

Think about activities you already do where you can allow your mind to wander. It could be going for a walk, pottering around the garden or even folding laundry.

“We want you doing some kind of activity that you get some enjoyment out of, but that isn’t putting you in any sort of threatening environment,” says Perry.

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Get curious about your own thoughts

Once you’ve started to pay attention to your inner monologue, the next step is to create distance between you and your thoughts, something psychologists call cognitive defusion.

There are lots of different ways you can do this. One is to buffer the thought with extra words. If you’re thinking ‘I’m too slow’ try rewording it as ‘I’m thinking that I’m too slow’. Or go one step further: ‘I’m noticing that I’m thinking that I’m too slow’.

Dr Steven Hayes, the psychologist who originally developed ACT, even suggests giving your mind a name for some additional distance.

Another option is to sing the thought out loud. Or you can distil it down to one word and repeat it out loud, fast, for 30 seconds, until the word loses its meaning.

The goal isn’t to ridicule yourself, but to stop treating your thoughts as gospel and get curious.

“We want to be more conscious of asking is this a thought or is it a fact?” says Perry. “Most of the time, without doing this work, we believe everything is a fact.”

You might start to notice patterns or types of self-talk that keep cropping up. A common one, says Perry, is telling yourself you ‘should’ be able to do something. The word is loaded with expectations and pressure, and puts you in a lose-lose situation.

“If you [do the thing you feel you should be doing], it’s because you expected to, but if you don’t, you’ve definitely failed,” she says. “There’s constantly this gap between where you are and where you think you should be, and that’s where you beat yourself up.”

“‘Should’ is a word we’re really trying to catch when we’re trying to notice our thoughts,” says Perry. Instead, she suggests consciously reframing ‘I should’ thoughts to ‘I’m working towards’, or ‘I would like to’ thoughts.

When you reach a point where you notice your thoughts without getting caught up in them, you have an opportunity to think more clearly and respond to your circumstances with actions that better align with your values.

Work out what your values are

But what if your values aren’t something you’ve ever consciously thought about? Well, the experts say it’s time to start.

One way is to begin with a long list of options and cross out the ones you don’t care that much about, until you’ve whittled it down. (You can find lists specifically for this exercise online – simply search the term ‘list of values’.)

“It’s really hard, because most things on the sheet will be good things to do, but we’re trying to get to what’s genuinely at the core of who we are,” she says. “When you’ve got down to about 10 or 12, you’ll start to notice some themes showing up.” Ideally, you want to end up with just three values.

You can test your shortlist by thinking about how you’d react in a situation when someone violates one of them.

“For instance, at my local Parkrun there’s a guy who cheats and cuts the corners,” says Perry. “I can laugh about it, but I have a friend that I run with, and [it] infuriates them. It really annoys them. And I imagine that’s because they’ve got a value of fairness and justice.”

Another way to clarify your values is to put them in competition with each other. For example, what’s most important to you: creativity or generosity?

“Don’t judge what you lean towards, because this is who you are,” says Kashdan. “If you walk through the world trying to be the Dalai Lama when you want to be Jim Morrison, you’re not going to live the one life that you have a chance for.”

Harness negative emotions

Ultimately, mental flexibility is about ditching your inner drill sergeant and finding a bit more compassion for yourself. Once you understand what really makes you tick, you can work with your brain instead of against it.

In fact, there are some situations where you might want to go a step further than simple acceptance and choose to harness your negative emotions to propel you towards your goals.

For example, research shows that anger can help you find the courage you need for an uncomfortable confrontation, while envy can motivate you to improve your performance and outperform others.

The possibility of harnessing negative emotions is one reason why Kashdan thinks mental flexibility has the edge over positive thinking.

“We find that people who are able to do this better have a greater ‘Swiss army knife’ of coping strategies for dealing with stresses in everyday life,” he says.

But when you get tempted to turn that negativity towards yourself, hit pause and find some self-compassion instead.

This will save you from expending energy on wrestling with your negative thoughts, allowing you to channel that energy towards the things you value instead.

In fact, along with being something you can practise when your best-laid plans inevitably clash with reality, self-compassion could even change the way you think about your ambitions in the first place.

“When we’re setting our goals… we so often look at our weaknesses and the things we need to fix or improve,” says Perry. “But I would love to see more people focus on their strengths. Where are they already amazing? How can they do more of that?”

How to train your mind to be more flexible

A key part of mental flexibility is handling tough emotions. Here's how to spot difficult thoughts that might trip you up, and how to plan for future obstacles...

Find your triggers

It’s helpful to identify your ‘emotional prejudice profile’. This involves figuring out your attitude towards different emotions – your so-called ‘meta emotions’.

They could be anything, but as a starting point, think about: sadness, anger, fear, embarrassment, guilt, shame and boredom.

Do any trigger a particularly strong reaction? Do you find it easy to get angry, or maybe you find embarrassment intolerable?

Another approach is to reflect on the last time you experienced these emotions. Which felt the worst, lingered the longest or was hardest to shake off? Recognising these patterns is the first step toward building emotional flexibility.

“You need to know which [emotions] have their fishhooks in you, that suck you out of the present moment,” says Kashdan. These will be your potential stumbling blocks on the path to mental flexibility. Pay close attention when you notice them pop up.

Refrain from repeating old patterns

The next step is identifying your initial reaction to a particular thought or feeling, and finding a course of action that better serves you – both now and over the long term.

One way to reframe your thoughts is to think about the advice you would give to a friend who was having the same thoughts.

“We’re really good at giving other people advice and giving other people support when they feel negative emotions,” says Kashdan. “But for us, we’re like, ‘Suck it up! You can handle it – it’s no big deal’.”

Treat yourself as you would someone you really care about.

Another way is to think about how your future self would feel about your actions today. Say you disagreed with someone in a work meeting, for example – would your future self prefer that you kept the peace, or spoke out?

Playing with time in this way could help you to figure out if peacekeeping is really what you want to do in that situation, or if it’s simply a way to avoid conflict and the negative emotions that come along with it.

“What we do today creates and informs who we’re going to be in the future,” says Kashdan.

About our experts

Dr Josephine Perry is a chartered sports and exercise psychologist, based in London in the UK. She is a published author with books ADHD in Sport: Strategies for Success, Performing Under Pressure: Psychological Strategies for Sporting Success, The Ten Pillars of Success, The Psychology of Exercise and I Can: The Teenage Athlete's Guide to Mental Fitness.

Dr Todd Kashdan is a professor of psychology and founder of the Well-Being Lab at George Mason University, in the US. He is a published author, too, with The Art of Insubordination: How to Dissent and Defy Effectively, The Upside of Your Darkside: Why Being Your Whole Self-Not Just Your "Good Self- Drives Success and Fulfillment, Curious? Discover the Missing Ingredient to a Fulfilling Life, Designing Positive Psychology: Taking Stock and Moving Forward and Mindfulness, Acceptance, and Positive Psychology: The Seven Foundations of Well-Being.

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