Some people just see the world more darkly than others.
A group of scientists says that what people observe in everyday life may depend on their genetic blueprint. A particular gene, known to play a part in emotional memories, could also influence where people tend to focus their eyes and attention.
“People think there’s a world, and our brain just tells us about it,” said study author and Cornell University psychologist Adam Anderson. “What our brain tells us is filtered, and emotions really have a powerful influence on how we see the world.”
Subjects who had a specific form of a gene in which certain amino acids are missing, found in about half of Caucasians, had a heightened awareness of negative stimuli. For instance, these people might look down a busy city street and catch the shady character hanging out by the ATM rather than the jubilant children playing in the park. Or during a nature hike, they would focus on the slippery rocks instead of the breathtaking scenery.
Typically, the more emotionally stirring an event is, the more vivid the memory — think flashbulb memories like the moment you heard about 9/11 or JFK’s assassination. These, along with other emotionally charged memories, are stamped into the brain with the help of a chemical called norepinephrine.
Individuals with the missing amino acids in the ADRA2B gene have more norepinephrine in their brains, and as a result, “experience the flash of the flashbulb memory more intensely,” said lead author and University of British Columbia psychologist Rebecca M. Todd.
The new findings hint that not only is the gene linked to more vivid emotional memories, but it may also make people more prone to noticing the negative in real time.
“People who have this gene might have more intense memories because they experience them more strongly,” Todd said.
Similar to how our genetic makeup can affect our individual taste for foods, our DNA — along with culture, experience, and environment — can influence our brain chemistry so that we observe and focus on different parts of the world than the person next to us.
“It’s all about genes contributing to ways you perceive the sensory world,” Todd said. “The idea we take away is we really do live in different worlds.”
The researchers tested more than 200 people by bombarding them with a series of words shown in quick succession. Subjects were asked to pick out two words colored in green and shown half a second apart. The first word is typically easy to notice, but the second word often whizzes right by due to a phenomenon called attentional blink.
“Instead of your eyes blinking, your mind is blinking,” said Anderson. “Once your attention grabs onto something, your brain is already working on something and there’s no resources left.”
One way to get around attentional blink is if the second word has a strong emotional overtone. For instance, people will more easily recall the word “rape” or “orgasm” than “house” or “computer.” Those with the gene variation noticed dark words much better than upbeat ones, whereas those without the variation saw both equally well.
“This is a simple experiment, but there are probably pretty profound consequences to seeing negative things more readily,” said Anderson. “You’re more likely to believe the world is a bad place.”
The study was published online Thursday in the journal Psychological Science.
Other scientists have reservations. Duke University neuroscientist Ahmad R. Hariri doubts that any one common genetic variation could have any sort of profound behavioral effect on its own, especially in something as complex as our perception of the world.
“There is no ‘negativity gene’ nor will there be one in the future,” Hariri wrote in an e-mail. “Rather hundreds and possibly thousands of genes and the variation they harbor will interact with the environment over time to gradually shape our behaviors.”
Anderson agrees that the group’s discovery should not be dubbed “the negativity gene” just yet, since it can be hard to untangle how much of the negativity bias is hard-coded or environmental.
“Instead of thinking this is a genetic sentence that you were born with this negativity gene, think of it as a gene enhancing things related to your experience,” he said.
Meeri Kim is a freelance science journalist based in Philadelphia.