Voice intonations are first signs of anger or joy
While sight and hearing are both critical senses, obviously, sight does not allow for all-area coverage as sound does. Therefore, researchers were interested in discovering the speed with which people respond to auditory clues to sense danger, anget, excitement, joy, and other responses.
“We are interested in how fast our attention responds to the different intonations of the voices around us and how our brain deals with potentially threatening situations,” said Nicolas Burra, researcher for the psychology section of the Faculty of Psychology and Education Sciences (FPSE) at the University of Geneva (UNIGE) in Switzerland.
To examine the brain’s response to threats in the auditory environment, the researchers presented 22 short human voice sounds (600 milliseconds) that were neutral utterances or expressed either anger or joy. Using two loudspeakers, these sounds were presented to 35 participants while an electroencephalogram (EEG) measured electrical activity in the brain down to the millisecond. Researchers focused on the electrophysiological components related to auditory attentional processing.
They found that the brain is best able to quickly differentiate a happy voice from an angry one, attributed to a marker known as N2ac. N2ac is amplified for sounds that indicate anger, but must disengage after 400 milliseconds so that a cerebral marker of auditory attention, LPCpc, can take over. LPCpc is also stronger for angry voices.
The rapid detection of the source of a potential threat in a complex environment is essential and critical in crisis situations.