Verbal insults are equivalent to receiving “mini-slaps” on the face, according to a study that examined electrical activity in the brain triggered by insults, compliments and neutral words.

The study by a team of scientists in the Netherlands has documented electroencephalography (EEG) signals that emerge 200 to 250 milliseconds after the start of the insulting words, whether the insult is directed at the listener or at another person.

This so-called P2 waveform component of the EEG was more prominent after insults than after neutral words or compliments, did not depend on who the insult was aimed at, and continued to emerge even when insults were repeated.

“The exact way in which words can deliver their offensive, emotionally negative payload at the moment when the words are being read or heard is not well understood,” Marijn Struiksma, a neuroscientist at the University of Utrecht and the study’s lead author, said in a media release.

Struiksma and her colleagues designed an experiment in which 79 university students were exposed to statements from fictitious people containing fictitious opinions with no bearing on their real lives but with insulting words, compliments or neutral words, repeated many times.

The insulting words included “evil”, “liar” and “repulsive” while the compliments included “beauty”, “brilliant” and “impressive”. The neutral words the participants heard included “Dutch”, “girl”, “participant”, “student” and “woman”.

The researchers found that verbal insults can impact people even under experimental conditions devoid of any real human interactions, with statements from fictitious people, and whether the insults were directed at the listener or to a third person.

“Our study shows that in a psycholinguistic laboratory experiment without real interactions between speakers, insults deliver lexical mini-slaps in the face,” the researchers wrote in their study, published on Monday in the journal Frontiers of Communication.

The findings show an increased sensitivity of the human brain to negative words compared with positive or neutral words. The insult immediately captures the brain’s attention -- the P2 waveform component of the EEG spiking within a quarter of a second after the start of the insulting words.

Scientists do not yet know the exact significance or source of the P2 waveform within the brain. But earlier research suggested that it emerges early in response to triggers and likely marks additional attention brought on rapidly and automatically by emotional or unexpected events.

The study’s findings, the researchers said, underline human sensitivity to undesirable social behaviour.

“For members of an ultrasocial species, that depend(s) on cooperation, reputation, respect and interpersonal trust, getting slapped in the face or seeing somebody else suffer that fate is a highly salient event regardless of the precise context,” the researchers wrote.

“It should be no surprise that the verbal equivalent is similarly evocative.”