According to a Sutton Trust report, extroverts are more likely to be successful than introverts - success being defined as earning more than £40,000 per year. While we can take issue with that as a definition of achievement in life, teachers can usefully reflect on how they might support their pupils in becoming more extrovert and thus, according to the evidence, increase their earning power.

I’m interested in leadership and so, when I see a group of pupils in a school corridor or several people walking together along a street, I often play the guessing game of “Who is the group leader?” Sometimes the answer may be more than one person, but there is often one who stands out from the rest. I have never been able to isolate the factors that single out the leader - it can be the way they walk, the way they talk to the others, or the way the others look at them. I have no way of knowing whether my conclusion is the correct one, which makes the game particularly unsatisfying!

Similarly with politicians: which prime ministers would you consider to have been the most natural leaders - David Cameron, Gordon Brown, Tony Blair, John Major, Margaret Thatcher? What about Jeremy Corbyn and Nicola Sturgeon? Which of these have the magic ingredient - and which don’t?

Which teachers do you know who appear to be natural leaders?

If you are interviewing for a new teacher, or especially a new school leader at any level, you will be looking for people who show leadership attributes. How much credit do you give to people who appear to be more extroverted?

For many years I was a maths teacher and you may know that the answer to the question “What is the difference between an extrovert maths teacher and an introvert maths teacher?” is that the extrovert maths teacher looks at the other person’s shoes. But you can have good introvert maths teachers, too. And leadership isn’t much more than appearance and first impression.

So it’s not all about being extrovert. In any leadership role, however - and all teaching jobs are leadership roles - you need to have personality and be able to project it.

In the Sutton Trust research, being an extrovert is defined as being assertive, talkative and enthusiastic, and it is important to recognise the study’s conclusion that extroverted people are less likely to come from poor backgrounds. These people are more likely to display openness, imagination and intellectual curiosity, and to have higher aspirations. Social skills, the researchers point out, are increasingly important in the labour market and this puts more deprived young people at a disadvantage in the competition for jobs, as well as for places at universities that use interviews for selection.    

So education secretary Nicky Morgan has a point when she says that schools should develop character in young people, an aspect of the curriculum that has been championed by Whole Education and other bodies for some years. A knowledge-based curriculum is important, but it must be balanced by the planned development of skills and personal attributes that helps to make young people the fully rounded citizens that parents want their children to grow into and employers want to take on to their workforce. Now we have the evidence from the Sutton Trust that this approach increases the earning, as well as their learning, power of young people. 

This is particularly important for less advantaged young people, who do not get as many opportunities outside school to develop skills and personal attributes - to become more self-confident and extroverted, for example - as their more fortunate peers. A very important part of closing the gap is giving young people these opportunities, as well as the high-quality teaching that should be at the top of every school’s list of closing-the-gap aims.

Disadvantaged young people need a both/and curriculum, just as much as the David Camerons of this world, for whom being extroverted and high-earning was seemingly part of their birthright and expensive education.

The Sutton Trust study concludes that schools and universities should provide students with training in employability skills and interview techniques and, like most studies, that more research is required to find out the best ways to instil positive personality traits in young people. That’s what schools in the Whole Education network are trying to do; it is why the Education Endowment Foundation is currently running six different projects to find the best ways to instil character traits like grit and self-confidence; and it is what all schools should be trying to do for all their disadvantaged young people. Then, perhaps, more disadvantaged young people will become leaders and earn over £40,000 a year - and fewer of our prime ministers will come from Eton.

John Dunford is chair of Whole Education and was formerly a secondary head, general secretary of the Association of School and College Leaders and national pupil premium champion. He tweets at @johndunford