Professor Rebecca Todd, from the University of British Columbia, who led the research, said it supported the idea that 'people experience emotional aspects of the world partly through gene-coloured glasses - and that biological variations at the genetic level can play a significant role in individual differences in perception'.
The researchers showed 207 healthy college-aged volunteers a series of positive, negative or neutral words in rapid succession. Study participants were asked to type words that they remembered onto a computer.
Participants who carried the ADRA2b deletion - a genetic variant known to be linked with susceptibility to intrusive traumatic memories - were more likely to recall negative words than others. This association remained after researchers controlled for sex, working memory, anxiety, depression and history of childhood abuse.
The ADRA2B gene influences the hormone and neurotransmitter noradrenaline. The deletion variant - present in around half of the study participants - is found in over half of caucasians but is significantly less prevalent in other ethnicities.
Professor Todd commented: 'These individuals may be more likely to pick out angry faces in a crowd of people. Outdoors, they might notice potential hazards - places you could trip, loose rocks that might fall - instead of seeing natural beauty'.
The researchers say their work is an attempt to unpick how genetics, combined with cultural background and life experiences, shape individual differences in emotional perception. 'For a long time we'd look at cognitive processes as if they're universal', Professor Todd told the National Post. 'Now there's a lot more data coming out saying they're influenced by many things'.
Although it is early to foresee any clinical implications of the study, the researchers say that the bias towards negative stimuli for ADRA2B deletion carriers may help predict increased vulnerability to post-traumatic stress disorder.
The study was published in the journal Psychological Science.