Pupils used to tell Pam VandenBurg that they were always being left out of playground games.
"Girls would come to me saying, 'She never lets me play,'" the special-needs co-ordinator said. "Or they say 'I'll never have any friends.' We used to spend a lot of time trying to unpick what happened and trying to be fair to everyone."
Working with Dr Kelly at University College, London, Ms VandenBurg piloted a 12-session resilience programme at Sacred Heart primary in Barnet, north London. It encourages pupils to question automatic, pessimistic thoughts. Pupils discussed how they would respond to a series of hypothetical scenarios. But they were also encouraged to talk about events in their own lives: all the pupils signed a confidentiality contract before the programme began.
The scheme, developed by Pennsylvania University, also uses cartoon characters to illustrate different ways of thinking. So Sherlock Holmes looks for evidence for his assumptions, while Chicken Little fears that the sky is falling in.
Pupil participants have learnt to question their assumptions independently. And they are able to apply this reasoning to the classroom, questioning whether they are "always bad at maths" or whether failure is a sign that they could work harder.
"It doesn't mean they're all perfectly calm little angels now," Ms VandenBurg said. "That would be unrealistic. But questioning your attitudes can affect some children quite profoundly."