Negativity bias is a form of cognitive bias which causes humans to subconsciously place more significance on negative events than positive ones, affecting behavior and cognition.
There are four demonstrated forms of negativity bias: negative potency, negative gradients, negativity dominance and negative differentiation. Negative potency gives a negative event or object more subjective weight than an equally positive event or object. For example, criticism is more likely to be remembered than praise. Negative gradients are closely related to negative potency. This aspect of the negativity bias makes negative events seem more negative as they come closer than positive events seem more positive. In other words, although positive and negative events will incite more and more emotion as they approach, this effect will be stronger with negative events than positive ones. For example, an approaching surgery will incite more and more anxiety as the date comes closer; an impending party or celebration will bring more excitement as it comes closer, but the increase in positive emotion will not be as high as the increase in negative emotion.
The next type of negativity bias, negativity dominance, makes the sum of all aspects of a situation seem more negative than positive. For example, if a person who has consistently performed well makes a mistake right before being reviewed for a promotion, they might be passed over for the promotion because the one mistake outweighs all of their previous good work. Conversely, someone who consistently performs poorly would not be awarded a promotion for doing well on one project. This type of negativity bias is especially important in product, software and website design and testing, because if a user finds something they dislike about a product they will most likely feel negatively toward the product as a whole.
Negative differentiation is a type of negativity bias which causes negative events or emotions to seem more complicated and require more cognitive attention. This is evidenced by the much higher number of words in the English language, and most other languages, describing negative emotions than positive ones.
Many psychologists agree that the negativity bias evolved as a survival technique. Assuming the worst of a situation that turns out not to be dangerous is much safer than not expecting danger that turns out to be present. The negativity bias also affects learning to promote survival: Both humans and animals have been shown to learn a behavior more quickly when exposed to negative stimuli than positive stimuli, sometimes even after being exposed to an extreme stimulus only once (such as in the case of taste aversions or phobias). This is because of the amygdala, the part of the brain most responsible for anger, fear and anxiety, sends negative information directly to long-term memory to provoke the fight-or-flight response, while positive information takes longer to reach memory.
The negativity bias has been studied extensively. The four different types of negativity bias were first described by researchers Paul Rozin and Edward Royzman in 2001. The negativity bias has also been shown to affect brain activity; more electrical activity shows up on brain scans in response to negative stimuli than positive stimuli.