By Hara Estroff Marano, published on May 1, 1999 - last reviewed on January 23, 2015
Why do political smear campaigns outpull positive ones? The
nastiness makes a bigger impact on your brain.
And that, says Ohio State University psychologist John T. Cacioppo,
Ph.D., is due to the brain's "negativity bias": it is built with a
greater sensitivity to unpleasant news. The bias is so automatic that
Cacioppo can detect it at the earliest stage of cortical information
In his studies, Cacioppo showed volunteers pictures known to amuse
positive feelings (such as a Ferrari or a pizza), negative feelings (like
a mutilated face or dead cat) or neutral feelings (a plate, a hair
dryer). Meanwhile, he recorded event-related brain potentials, or
electrical activity of the cortex that reflects the magnitude of
information processing taking place.
The brain, Cacioppo says, reacts more strongly to stimuli it deems
negative. Thus, our attitudes are more influenced by downbeat news. Our
ability to weigh negative input so heavily evolved, he explains, to keep
us out of harm's way.