In A Nutshell
The tendency to focus on the negatives rather than the positives is a genetic trait, similar to the way hair and eye color are determined by genetic variations. Some people are just born to be pessimists.
The Whole Bushel
About 32 percent of people are born with something called ADRA2B-deletion, a small genetic variation that forces them to remember negative experiences more vividly than positive ones. And as a side effect, they also have a tendency to dwell on their negative experiences. There’s not much they can do about it; it’s written into their genes. For these people, the glass is always half-empty, and probably cracked.
The ADRA2B gene is involved in a very specific function: It detects and stores chemical signals from memories that have an emotional impact. It has no effect on emotions themselves, or memory, but when the two are combined, ADRA2B jumps into action and influences the way that memory was stored—and how easily it can be recalled later. For example, if you were in a car accident as a child, ADRA2B is the reason that memory comes back with so much clarity. But when you think about what you had for breakfast two days ago, the memory isn’t nearly as clear because there wasn’t an emotional factor (unless you really love waffles).
And since ADRA2B is so strongly tied to emotion, it also determines your emotional state when recalling that memory. If the memory was a happy one, you tend to get happier thinking about it, and vice versa for sad memories. And as far as ADRA2B is concerned, there’s no gray area in between—memories are simply either positive or negative. Losing your puppy for an afternoon is the same as, say, losing your parents.
In most people, the tendency to notice something emotional is equal—they notice the good and the bad. But for people with the ADRA2B variant, their brains pick up on negative signals more easily than positive ones. When researchers at the University of British Columbia brought together 200 volunteers to test the effect, they found that people with ADRA2B-deletion consistently focused on negative stimuli.
The test was simple. Eighty-four words were flashed in front of the subjects, one at a time for a fraction of a second each. For most people, recognizing a single word a fraction of a second after another word is difficult because of a phenomenon called attentional blink. But if a word has an emotional charge to it, the brain is quicker at picking it up (for example, “death” has an emotional charge; “house” does not).
At the end of the test, the volunteers were asked to recall as many of the words as possible. The people with a normal ADRA2B gene recalled positive and negative words equally. But for the people with a genetic variant, the remembered words were overwhelmingly negative. At the speed the words were flashed, they didn’t consciously pick out the negative words—their brains are just better at noticing them. A different study showed that survivors of the Rwanda genocide were more likely to experience terrifying flashbacks if they carried the gene variation.
But there’s a bright side (although 32 percent of you might not agree): Even though the ADRA2B-deviants are more attuned to negative things, they still have better memory overall. So that’s a plus.