If you are a cheery soul whose glass always seems half full, you can thank your parents.
You will probably be pleased to learn some of us are born optimists who have inherited a 'happy gene'.
The finding may help to explain why some people are always miserable while others tend to look on the bright side.
Professor Elaine Fox at Essex University showed more than 100 people positive and negative pictures on a computer screen, such as growling dogs and smiling children.
Using a revolutionary computer based therapy, she was able to measure which ones they concentrated on.
Volunteers supplied a sample of their DNA and they were tested to see which version they carried of the 5-HTTLPR gene which affects levels of the 'feel-good' chemical serotonin.
We inherit either two 'short' versions, a long and a short versions or two 'long' versions of the gene.
Those with two short versions of the gene managed to focus on the positive images and avoid getting upset by the negative ones, according to the research published online in Biological Psychiatry.
Strangely this 'short' version of the gene is the same one which has been associated with making people feel anxious and depressed and it suggests these people have a'very emotional' response to their environment.
Professor Fox said: 'When times are really good, it is those with the highly reactive short genotype who really benefit.
Bron: Daily Mail online
By Tamara Cohen
Last updated at 2:41 AM on 10th September 2011