Many UK children have become less confident about succeeding in life by the time they leave school, a report says.
The study by think-tank Demos says some pupils feel school is just preparing them for exam success.
It urges the government to help schools and colleges explore how self-belief, perseverance and resilience can be instilled in pupils.
The government said it had allocated funds to promote character education.
The Mind Over Matter report is based on interviews with experts, a survey of 1,000 teenagers and a round-up of previous academic research.
But its own survey suggests there is a steady decline in children's self-belief between 14 and 18.
Final-year students are half as likely to feel happy (33%) as 14-year-olds (60%), it says.
These 18-year-olds are also more likely to think there is too much focus on exams rather than preparing for life in general.
The report also finds gender discrepancies, with 39% of girls reporting feeling happy compared with 50% of boys.
Learning from failure
It says there is an increasingly robust body of research detailing how "non-academic factors such as resilience, grit and empathy can have a profound impact on young people" and their ability to succeed.
It calls the adoption and practice of this approach "a growth mindset" and says the idea behind it is simple.
"If we believe our intelligence and abilities are not fixed at birth, but can be developed through effort - if we have a 'growth mindset' - then we are more likely to look for challenges to see failures and setbacks as learning opportunities, and ultimately to achieve more personally and professionally," it says.
By contrast, those with "fixed mindsets" conclude they will never be able to achieve certain things when faced with setbacks.
The research argues that more needs to be done, inside and outside school, to give youngsters this more positive mindset and the self-belief they need to be successful, confident adults.
Report author Louis Reynolds said: "Mindsets matter - they can hold us back or propel us forward to achieve more. This insight needs to be applied more systematically in our education system.
"Teachers, policymakers and education experts increasingly agree that a young person's wellbeing, success in education and overall life outcomes are affected by much more than academic grades - including their character attributes, and their social and emotional skills."
A spokesman for the Department for Education said: "We want all young people to have the opportunity to develop a wider set of skills to help them succeed at school and contribute to society.
"All schools should create a happy and supportive environment helping children develop important life skills, such as resilience to support their academic attainment and give them the qualities that employers value.
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