http://www.newscientist.com/Positive people may owe their optimism to a gene variant that helps them dwell on the good and ignore the bad.
That's the conclusion from a study examining people's subliminal preferences for happy, neutral, and threatening images.
Volunteers who had inherited two copies of the "long" variant of 5-HTTLPR – a gene that controls transport of the mood-affecting neurotransmitter serotonin – showed clear avoidance of negative images, such as fierce animals, and a clear preference for positive ones, such as puppies. People with this variant combination are dubbed "LL" carriers.
The effect wasn't seen in volunteers with at least one version of the "short" variant of the same gene – these people showed no strong preference whatever the content of the images.
Time lapse
In repeated tests, the 97 volunteers had less than a second to identify dots hidden in one or other of a pair of adjacent images. Each pair contained a neutral image alongside one that was either positive or negative.
In repeated tests, the 97 volunteers had less than a second to identify dots hidden in one or other of a pair of adjacent images. Each pair contained a neutral image alongside one that was either positive or negative.
The researchers found that LL volunteers took 18.3 milliseconds longer on average to spot the dots in a negative rather than neutral image, suggesting a subliminal aversion to bad images.
Conversely, they noticed the dots 23.5 milliseconds sooner in the positive images, such as cuddly puppies, than in the neutral ones, suggesting they were subliminally drawn to them. "It sounds very small, but in terms of attentional time, it's consistent," says team leader Elaine Fox of the University of Essex in Colchester, UK.
Optimistic streak
Fox and her colleagues conclude that the LL volunteers may be primed to seek out positive events and ignore negative events.
Earlier studies had revealed a tendency for negativity and anxiety among individuals with at least one short variant of the gene, but the study is the first to reveal an optimistic streak in LL individuals.
"A number of mechanisms may contribute to this difference, and the authors have provided good evidence that attentional bias in the processing of emotional stimuli may be one of those mechanisms," says Turhan Canli, who has studied the same phenomenon at Stony Brook University in New York.
Journal reference: Proceedings of the Royal Society B (DOI: 10.1098/rspb.2008.1788)
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