The majority of participants, who used the app for three months, said that they wanted to reduce their emotional vulnerability, increase their conscientiousness or extraversion.

Those who participated in the intervention for more than three months reported greater success in achieving their change goals than the control group who took part for only two months, indicated the findings published in the journal Proceedings of the National Academy of Sciences.

"The participants and their friends alike reported that three months after the end of the intervention, the personality changes brought about by using the app had persisted," said researcher Mathias Allemand from the University of Zurich in Switzerland.

"These surprising results show that we are not just slaves to our personality, but that we can deliberately make changes to routine experience and behaviour patterns," Allemand added.

According to the study, personality traits such as conscientiousness or sociability are patterns of experience and behaviour that can change throughout our lives.

Individual changes usually take place slowly as people gradually adapt to the demands of society and their environment. However, it is unclear whether certain personality traits can also be psychologically influenced in a short-term and targeted manner.

For the study, the team included around 1,500 participants, who were provided with a specially developed smartphone app, called PEACH, for three months and the researchers then assessed whether and how their personalities had changed.

The five major personality traits of openness, conscientiousness, sociability (extraversion), considerateness (agreeableness), and emotional vulnerability (neuroticism) were examined.

The app included elements of knowledge transfer, behavioural and resource activation, self-reflection, and feedback on progress. All communication with the digital coach and companion (a chatbot) took place virtually.

Close friends and family members also observed changes in those participants who wanted to increase expression of a certain personality trait. However, for those who wanted to reduce expression of a trait, the people close to them noticed little change.

The app was developed as a research tool. In the future, however, it is thought that research apps such as PEACH will be made widely available, the researchers said.