The key to success isn't raw talent or intelligence, it's much dirtier than that.

There’s a video on Youtube of Will Smith that does the rounds every few months. He’s asked what sets him apart from others who might have similar aspirations. This is his response:

“The only thing that I see that is distinctly different about me is I’m not afraid to die on a treadmill. I will not be out-worked, period. You might have more talent than me, you might be smarter than me, you might be sexier than me, you might be all of those things – you got it on me in nine categories. But if we get on the treadmill together, there’s two things: You’re getting off first, or I’m going to die.”

In psychological terms, Will Smith is referring to ‘grit‘ – a characteristic that psychologist Angela Duckworth has been studying for over a decade. A ‘gritty’ person has passion and perseverance for very long term goals, is mentally tough, has stamina, is highly motivated, and is willing to ‘stay the course,’ despite inevitable challenges and barriers.

And according to Duckworth, grit - not talent or IQ or emotional intelligence - is the key to success.

As Wired puts it, "Success in the real world depends on sustained performance, on being able to work hard at practice. Our most important talent is having a talent for working hard."

While research on 'grit' started just over 10 years ago, similar concepts were explored throughout the 20th century. Conscientiousness, hardiness, resilience, ambition, need for achievement - whichever term you use, psychologists have made a point of separating latent ability (eg IQ), from the accomplishment of work.  In fact, as far back as Aristotle, people have noticed tenacity and persistence play a highly significant role in determining success.

But Angela Duckworth's new book 'Grit: The Power of Passion and Perseverence', released earlier this month, is sure to bring the concept of 'grit' well and truly into the limelight.

A Harvard graduate and recipient of the 2013 MacArthur "genius" grant, Duckworth sees grit as one of her most valuable characteristics. Speaking at the Education Writers Association national seminar, she said if she could go back to her childhood, she would tell her father grit is an overlooked element of success.

"I would say, 'Dad, you claim I'm no genius. I won't argue with that. You know plenty of people who are smarter than I am.' I can imagine his head nodding in sober agreement.

'But let me tell you something. I'm going to grow up to love my work as much as you love yours. I won't just have a job; I'll have a calling. I'll challenge myself every day. When I get knocked down, I'll get back up. I may not be the smartest person in the room, but I'll strive to be the grittiest.'

And if he was still listening: 'In the long run, Dad, grit may matter more than talent.' "

Watch Angela Duckworth's TED talk. Post continues after video. 

For those with a background in education, the idea that grit matters more than talent probably comes as no surprise. It's rarely the smartest students who get the highest marks or the most academic success. Instead, it's those students who thrive when they're challenged, put in the most effort, and remain passionate and committed to achieving long-term goals.

In fact, Duckworth explains that grit has a slightly inverse relationship with talent - suggesting the process of struggling to master a skill, rather than having it come easily, is highly beneficial. Ultimately, facing challenges and persisting through them is far more valuable than your raw ability.

So, what does this mean?

First, it should encourage us to change the value judgments we make when we see success. Often, when we think about the most successful people in particular fields, we ascribe their performance solely to talent. Steve Jobs and Mark Zuckerberg are geniuses. Tiger Woods was born to play golf. Sheryl Sandberg is more innovative and clever than I'll ever be.

But we all know there's more to the story. People don't stumble upon success solely because of something they're born with. All studies show that other qualities - particularly mental toughness or grit - are far more important than any level of talent.

Second, it gives us something to work on. According to Duckworth, people can become gritty. It can be developed internally, through mindfulness practice for example, and externally, by supportive cultures that encourage deliberate practice and frequent feedback. However, the most important part of building grit is the idea of a 'growth mindset.'

Well, apparently it's something that can be developed internally, through mindfulness practice for example, and externally, by supportive cultures that encourage deliberate practice and frequent feedback. However, the most important part of building grit is the idea of a 'growth mindset.'

Developed at Stanford University by Carol Dweck, a 'growth mindset' refers to the belief that intelligence or competence is not fixed, and can change with effort. Dweck's research has demonstrated that when children learn about neuroplasticity (the potential of the brain to change and adapt to meet your needs), they're more likely to persevere in the face of failure, believe failure to be constructive, and not see failure as permanent.

So really, a large part of success is the way we perceive and respond to failure.

Personally, the concept of grit has made me hopeful. I feel more empowered knowing that achievement has more to do with trying hard than talent. It's a relief - because God knows I'm never going to be the smartest or the fastest or the most gifted.

Perhaps simply learning about grit can make us more gritty, and it seems like a particularly important lesson for women who are routinely reminded of their countless barriers to success. Given that many of our icons of success are men, it's crucial to remember this is only the case because their motivations have been career-related while women's have been elsewhere (thanks #patriarchy).

It's a concept adults and children alike need to hear and see more often: success (in its numerous forms) doesn't come easily - and is the result of hard, unglamorous, challenging work.