The study found that 15-year-olds told more coherent stories about turning points in their lives if their mothers had been taught the new conversational techniques 14 years earlier.

These adolescents also reported fewer symptoms of depression and anxiety compared to adolescents in the study whose mothers had conversed with their toddlers as usual.

Published in theJournal of Personality, the research is a follow-up of a reminiscing intervention in which 115 mothers of toddlers were assigned to either a control group or given training in elaborative reminiscing for a year. Elaborative reminiscing involves open and responsive conversations with young children about everyday past events, such as feeding ducks at the park.

Project lead Professor Elaine Reese, of the Department of Psychology, says adolescents whose mothers had participated in the earlier coaching sessions narrated difficult events from their lives -- such as parental divorce or cyber-bullying -- with more insight into how the experience had shaped them as people.

The research, initially funded by the Marsden Fund of the Royal Society Te Apārangi, is the first to show long-term benefits of mother-child reminiscing for adolescents' development.

"Our findings suggest that brief coaching sessions with parents early in children's lives can have long-lasting benefits, both for the way adolescents process and talk about difficult life events and for their well-being," Professor Reese says.

"We believe parents' elaborative reminiscing helps children develop more complete, specific, and accurate memories of their experiences, providing a richer store of memories to use when forming their identities in adolescence. Elaborative reminiscing also teaches children how to have open discussions about past feelings when they're no longer in the heat of the moment."

She hopes parents and policy makers realise the importance of early childhood as the ideal time for starting to have positive conversations with children, and to know that these conversations can make a difference as children grow older.

"The ultimate goal is to encourage parents to have more sensitive and responsive conversations about events in their children's lives."

Lead author and clinical psychologist Dr Claire Mitchell says a great deal of research now shows well-being can drop dramatically in adolescence.

"For some young people, this dip is the beginning of more severe mental health issues that can be difficult to treat. Thus, it is important to find ways to prevent mental health difficulties earlier in life if possible.

"As a parent of a toddler myself, I can confirm that these elaborative reminiscing techniques are enjoyable and easy to learn. Our study helps pave the way for future work with parents of young children to promote healthy interactions from the beginning that could have enduring benefits," she says.

The researchers intend to continue the study, following up with participants in emerging adulthood to determine any ongoing effects of their mothers' elaborative reminiscing.