“It’s important that, as parents and teachers, we don’t demonise being quiet,” said Carol Craig, chief executive of the Glasgow-based Centre for Confidence and Wellbeing.

Many Scots would be deemed lacking in confidence if extroversion was a barometer, since it was “well known” that about 40-45 per cent of people in the country were quiet and introverted. “There’s nothing wrong with them; they’re just quiet,” Dr Craig told the National Parent Conference in Glasgow last week.

“Confidence should be about the confidence to do specific things,” she said. Previous experience of success was best for building confidence, and the acquisition of skills was also important. “We’re in danger of playing down their importance,” she added.

Strong role models, an hour a day of exercise and outdoor learning could also help build confidence.

Handing out undiscriminating praise, however, was counter-productive. Instead, “what children will appreciate more is taking the time to be interested in what they’re doing”.

The idea that intelligence was fixed at birth was also dangerous. It undermined the importance of hard work and reduced the resilience of children who flew through the first years of school, but became distressed when their “cleverness” alone was not enough. “The worst attitude young people can have is to believe that hard work shows you’re not clever,” said Dr Craig, adding that Albert Einstein spent 15 hours a day studying to achieve success.