8:43am UK, Thursday May 19, 2005

If you want to change your life then forget about doing it on January 1, a scientist says.

Psychologist Dr Cliff Arnall says increasing sunlight, longer days and a general Spring feelgood factor means that May 18 is the perfect day to reflect on your lot and change it for the better.

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All too much? Well today's the day to change it all

Dr Arnall looked at factors that contribute to people motivating themselves to change.

He came up with the formula M x O + Bh (H+R) x S, where M is for motivation, O opportunity, Bh proximity to a Bank Holiday, H for the increasing hours of daylight, R reflection time and S is success.

Put simply, the formula means we are more likely to come up with a plan on May 18 to change our lives - and stick to it.

"By May, with more time for reflection and summer on the way, there is lots of positive energy around associated with renewal," he said.

Dr Arnall was challenged to work out the date by the Department of Education's Get On campaign.

It was Dr Arnall who earlier this year announced to the world that January 24 was the most depressing day of the year.

Again, he produced a similar formula to back up his theory based on the number of daylight hours and proximity to Christmas.