Michael Mosley has investigated the science of personality and discovered that our outlook on life is not fixed and unchangeable.
By regularly practicing two mental exercises - mindfulness and cognitive-bias modification - and with no drugs or therapy he felt happier.
Cutting edge tests showed that within just seven weeks his brain activity became less characteristic of a pessimistic and anxious person.
Study has shown that on average, being optimistic can add more than seven years to a life - four years more than if a cure for cancer was found.
The idea behind the excerise was to train his brain to look for positive images. By regularly doing this, it is thought the brain learns to tune into positive thoughts more easily. After seven weeks, Mr Mosley felt his mood lifting, he started sleeping better and felt more optimistic. He then returned to the lab to see if his brain had in fact changed.
Mr Mosley was told the ‘asymmetrical’ levels of his brain activity had become more equalised – a strong indicator he had become more optimistic.
In addition to this, his scores when reacting to the brain training game had changed. He reacted more quickly to happy faces and more slowly to sad faces, indicating he was not seeking out negativity as much.
Dr Mosley told BBC2 programme, Horizon: The Truth about Personality: ‘I feel quite frankly astonished that you can notice that much change in just seven weeks. I set out to see if it was possible to change my mind and I think I might have done it. I am absolutely thrilled.