Negativity may be a genetically controlled characteristic, The Washington Post reports. The claim is based on a study in Psychological Science that tested 200 people by flashing a series of words in rapid succession and asking participants to recall two of the words. The theory is that once the participant devoted their attention to remembering the first word, they would have difficulty remembering the second word. This effect can be minimized by using emotionally charged second words, such as “rape.” Scientists found that individuals with the deletion variant of ADRA2B, which is associated with increased levels of norepinephrine in the brain, were more likely to remember the emotionally charged words than non-charged words, whereas those without the mutation saw both types of words equally well. The variation, thus, seems to affect how people relate to environmental stimuli, and may control intensity of memories.