Negativity bias
Bad is psychologically stronger than good.
What it means
Negativity bias is the principle that negative events, emotions, and information have a greater impact on the psyche than equally intense positive ones — they capture more attention, weigh more heavily in judgment, are processed more thoroughly, and are remembered better. The asymmetry is thought to be adaptive: across evolutionary time, failing to respond to a threat was far costlier than failing to exploit an opportunity, so a mind tuned to give bad things extra weight had a survival advantage. The effect appears across domains — first impressions are more readily damaged than burnished, losses outweigh gains (its motivational cousin, loss aversion), one criticism can drown out many compliments, and bad news dominates attention. A boundary condition is the 'positivity offset': in the absence of strong negative input, people maintain a mildly positive default that motivates exploration, and the relative weight of negative information can shift with age and context. It matters because it shapes risk perception, relationship satisfaction (where a high ratio of positive to negative interactions is needed to thrive), the appeal of alarming news, and the tone of political and media discourse.
Examples
One harsh review stings more and lingers far longer than several glowing ones, even when the praise is more numerous.
A pilot remembers for years the one flight where a warning light came on, and almost nothing about the thousand routine landings either side of it.
In a marriage, one cutting remark can undo a week of small kindnesses, which is why it takes many good exchanges to offset a single bad one.
First described in Rozin & Royzman; Baumeister et al. (2001).