Emma Watson during her viral address at the launch of #HeForShe at the UN in September last year.

Nearly 40 years after it was first identified, imposter syndrome is still rife in society. Linda Kelsey, a victim herself, reports.

It was back in 1978, at the age of 26, when I was features editor of Cosmopolitan magazine, that a groundbreaking piece of work by two academics at Georgia State University found its way to the mainstream media.

Entitled "The imposter phenomenon in high achieving women", it detailed the results of five years of working with 150 successful women, ranging from undergraduates and PhDs to lawyers and teachers, who persisted in believing they were not very bright and had somehow fooled anyone who thought otherwise.

That's me to a T, I thought, while jumping to the conclusion that, as a university dropout, I had far more claim to being an imposter than any of the genuine high achievers.

They might be victims of a syndrome, but I really had reason to doubt myself, compared with the outgoing Oxbridge graduates who seemed to dominate the industry in which I worked. This lot might have imagined themselves to be phonies, I told myself, but I was the real deal, a genuine phony.

On the back of the research we ran a story in Cosmo asking, "Are you a victim of imposter syndrome?" and were flooded with letters from readers who were young and ambitious and slowly climbing the career ladder while convinced they were going to be unmasked at any moment.

Now, 37 years on, it seems there's little change... In an interview in this month's Vogue, the talented, beautiful, super-bright and wealthy young actress Emma Watson has said that despite her success she feels like an imposter. It is a recurring theme for Watson.

"Any moment someone's going to find out I'm a total fraud – I can't possibly live up to what everyone thinks I am."

A couple of years back she told an interviewer: "Any moment someone's going to find out I'm a total fraud - I can't possibly live up to what everyone thinks I am."

If it weren't for the fact that I so identify with what she is saying, I might be inclined to accuse her of false modesty. After all, the Harry Potter star is also a UN Women Goodwill Ambassador (who recently delivered a headline-generating speech on gender equality at the UN headquarters), and a graduate of Brown, one of America's top universities.

But I don't think Watson is falsely modest. She is, like so many high-achieving women, a victim of that syndrome psychologists identified so long ago. Women such as Facebook's chief operating officer, Sheryl Sandberg, comedian Tina Fey and the late poet/essayist/playwright Maya Angelou have expressed similar sentiments. Watson is giving voice to what so many women know they shouldn't feel, but do.

In my own case, feeling like an imposter has dogged my every achievement. When I became editor of Cosmopolitan in 1985, I thought my bosses would soon realise their mistake. When I wrote three - moderately successful - novels a few years back, I was quite unable to claim the title novelist for myself. I felt it should be reserved for the infinitely more elevated likes of Margaret Atwood or Hilary Mantel. Sometimes, I pick up the books with my name on the cover and ask myself, did I really write that?

And when people invite me to talk at conferences, seminars and charity functions about my life and career, my first thought is always why on earth would they ask me?

I'm not claiming any of this is rational, but it is how I feel, even now at the age of 63.

When I meet educated young women today, they seem so much more confident, sassy and articulate compared with how I was in my youth. They outperform boys at school, and female undergraduates are increasing at a faster rate than male university students - yet there remains a huge disparity in overall levels of male and female confidence, which becomes especially apparent in the workplace.

Professor Marilyn Davidson of the Manchester Business School has, for several years she has been asking her students what they expect to earn, and what they deserve to earn, five years after graduation. On average, she reports, women come up with a figure that's 20 per cent less than the men.

Asking for what you deserve is a measure of confidence, self-belief and not thinking you're an imposter. Despite L'Oreal's persistent claim to the contrary women still don't think they're worth it.

Tina Fey has admitted to feeling similar sentiments as symptomised in imposter syndrome.

According to Katty Kay and Claire Shipman, authors of The Confidence Code, there remains a vast confidence gap that separates the sexes. It starts in school where many girls are first rewarded for being good, instead of being energetic, high-spirited or even pushy. Being "good" in the classroom may pay off but, say the authors, fails to prepare us well for the real world.

Research shows that compared with men, women don't consider themselves as ready for promotions, predict they'll do worse in tests and generally underestimate their abilities.

In 2011, the Institute of Leadership and Management surveyed managers about their levels of confidence in their profession and half the female respondents reported self-doubt about their job performance and careers, compared with few than a third of male respondents. In other words we're more likely to feel like imposters all the way down the line.

My view is that, for women, confidence ebbs and flows throughout the life cycle, and this in turn impacts on our sense that we're frauds about to be found out. Academically confident girls who give up sport and become focused on their appearance and body shape in adolescence begin to question their worth in other areas.

A survey by the Girl Guides Association found that 87 per cent of young women felt they were judged on what they looked like, rather than what they could do, so perhaps it's little wonder that young women begin to downgrade their achievements.

Taking time out of the workplace for motherhood can sap confidence, while juggling work and parenting can make women doubt their ability to perform all their roles equally well and generate feelings of guilt. Women who work part-time often see themselves as offering less, instead of having the confidence to explain exactly the value of the experience they do offer.

Perfectionism is another confidence killer according to Kay and Shipman. Studies confirm it's mainly a female issue. We tend not to answer questions unless we're certain of the answer, or to submit a report until we've gone over and over it ad nauseam. Male colleagues take risks, women hold back until perfectly ready. And all of this feeds back into the uncertainty and self-doubt that makes you feel like an imposter.

Facebook's chief operating officer, Sheryl Sandberg.

The problem with us imposters is that we have unrealistically high standards for everything we do. It's all or nothing with us. If we don't know it all, we know nothing. If it's not perfect, it's a disaster; if we're not the best we're useless.

I am hopeful that, now I'm in my sixties, I'm finally beginning to get the better of my imposter tendencies. A fortnight ago I completed the degree in Arts and Humanties I've been studying for part time at Birkbeck College, University of London, the one I embarked on to make up for the one I failed to complete in my teens. And I got a First.

Instead of thinking "surely some mistake", I examined my record and was forced to recognise that no one else wrote those essays or took those exams for me. The achievement was real. And I did it on my own.

Every time I feel myself slipping I will try and take heart from Bertrand Russell who said: "The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt."

And from Sheryl Sandberg who has said: "There are still days I wake up feeling like a fraud, not sure I should be where I am." If the likes of Emma Watson and Sandberg can feel frauds and yet achieve what they have, maybe there are worse things than sometimes thinking you're an imposter.

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