Listen and learn: the hidden secret to spotting a liar

"Close your eyes. You're already twice as good as you were before. Our voices change in an instant. When you're hit by a surge of adrenaline, your fight-or-flight response triggers muscles around your larynx, making your voice high-pitched and wobbly. When you answer the phone to someone you love, your voice softens and deepens. When someone lies, the rhythm and intonation of their speech change. And, weirdly, you are almost twice as good at spotting that distortion if you only hear not see them speak."

"Our voices give away a huge amount of information with every sentence, and human beings are remarkably good at interpreting these subtleties. But what exactly are our voices revealing, and how do our brains process that information? I volunteered as a Samaritan at university. After the initial training, I spent hundreds of hours listening to callers as they talked about everything from unreciprocated crushes to financial crises to the death of someone dear. The listening role was vital Samaritans helps thousands of people a year but as I continued, I found myself getting more and more fascinated by voices and how we process the information they provide."

"For starters, human beings are brilliant at deducing information from just a few words, partly because our physique dictates many aspects of our voice. Voices are an instrument and they reflect our physical nature, says Prof Sophie Scott, the director of the Institute of Cognitive Neuroscience at University College London. If you think about a ukulele, a guitar and a violin, their sound is defined by the material they are made out of, the number of strings and how you play them. The voice is the same."

"We are good at telling height because taller people have longer vocal tracts and therefore produce lower vocal tract resonances. A man's voice is usually roughly one octave lower than a woman's. As we age, the cartilage of the larynx may harden, making a voice hoarser or weaker."

Voices change instantly with adrenaline and emotional state, affecting pitch, wobble, and softness. Lying alters speech rhythm and intonation, and hearing speech without seeing the speaker improves detection accuracy. Voices convey substantial information per sentence, and humans interpret subtle vocal cues effectively. Physical characteristics shape vocal production, so listeners can infer traits from limited speech. Taller people tend to have longer vocal tracts and different resonances, and men’s voices are often about an octave lower than women’s. Aging can harden laryngeal cartilage, leading to hoarser or weaker voices. Extensive listening experience can increase fascination with how vocal information is processed.

Read at www.theguardian.com