Mi-Hwa Park, of Texas university, believes that children who successfully work through their disappointment in the primary classroom are better equipped to handle the frustrations of adult life.

Ms Park studied pupils at a daycare centre in south Texas, observing their immediate reaction to disappointment, as well as their reactions a day after the event.

She found that children had many coping strategies. For example, when four-year-old Sarah was unable to make a paper flower, she put her head on her desk and cried. By contrast, when Justin was prevented by his teacher from playing with a friend, he hid his emotions and obeyed instructions.

“Children who suppressed feelings of disappointment I were perceived as better self-regulators,” said Ms Park.

But in interviews the next day, the children revealed more considered responses. Having practised flower-making at home, Sarah said: “I will ask the teacher to help me. Then I will practise it over and over until I can make it by myself.”

But Justin’s disappointment had not waned. “I don’t know why we can’t play together,” he said. He added that he was too shy to ask the teacher for an explanation.

Expressing negative emotions helped children to reflect on their feelings and consider other people’s viewpoints. If disappointments went unexpressed and unexplained, children were left with a sense of powerlessness.

“Children who do not know how to express disappointment in contextually appropriate ways may have difficulty establishing and maintaining interpersonal relationships,” said Ms Park.

She said teachers are often responsible for causing disappointment, either unintentionally or because they want to help pupils acquire realistic expectations of their own abilities.

“We encounter disappointment consistently in our daily lives,” she said.

“It is important that we learn to self-regulate I as children, because the consequences of our actions then are not as severe as when we are adults.”

* mihpark@mail.utexas.edu