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. We inherit either; two 'short' versions, a long and a short version 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.