Those who always see the glass half full have a genetically driven tendency to do so, scientists at the University of Essex have discovered.

Research published today (25 February 2009) identifies a genetic variation which is powerfully linked to a tendency to selective avoid negative images and to pay attention to positive information. These findings represent a breakthrough in understanding why some people are highly resilient to stress, which others are susceptible to the negative impact of stressful life events.

The study of almost 100 healthy individuals showed those with a variation in the serotonin transporter gene had a clear bias towards emotionally positive images and away from negative ones. This gene is known to impact on brain levels of serotonin, a chemical which is known to affect mood and well-being. Each of us carries either two short versions of this gene (SS), two long versions (LL), or one of each (SL). Those in the LL group showed the pattern of vigilance for good things combined with avoidance of bad things.

Lead researcher Professor Elaine Fox, from the Department of Psychology, explained: 'We have shown for the first time that a genetic variation is linked with the tendency to look on the bright side of life. This is a key mechanism underlying resilience to general life stress. The absence of this protection in the other forms of this genotype is linked with heightened susceptibility to anxiety and depression.'
The study, published in Proceedings of the Royal Society B, involved a standard test of selective attention whereby participants were shown pairs of pictures, one of which was either positive or negative and the other neutral, and researchers measured where their attention was drawn. All the participants gave DNA samples which were genotyped for the three variations of the promoter region of the serotonin transporter genes.

While a smaller study has previously been conducted among psychiatric patients, this study is the first to report gene-related variation in attentional bias in the healthy population. While carriers of the LL version of the gene were vigilant for positive images and clearly avoided negative ones, this protective pattern was completely absent in carriers of the S-allele (either the SS or SL variation).
Professor Fox's team is continuing this research by investigating whether by actively modifying people's biases their resistance to negative and traumatic life events can be enhanced.
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Notes to Editors
1. The paper: Looking on the bright side: biased attention and the human serotonin transporter gene by Elaine Fox, Anna Ridgewell and Chris Ashwin is published online on 25 February by Proceedings of the Royal Society B.

 2. The Royal Society is an independent academy promoting the natural and applied sciences. Founded in 1660, the Society has three roles, as the UK academy of science, as a learned Society, and as a funding agency.

3. The University of Essex is one of the UK’s leading academic institutions, ranked ninth for the quality of its research, and the top-ranked university for social science research. It has more than 9,000 students, studying at three campuses. Around one third of the students are drawn from more than 130 different countries overseas.

4. To speak to lead author Professor Elaine Fox, please contact Jenny Grinter in the University of Essex Communications Office on 01206 872400, e-mail: comms@essex.ac.uk.