People who speak with a rising intonation, reduced emphasis at the beginning of each syllable, and a slower speech rate are generally perceived as dishonest, according to a new study in the journal Nature Communications. After conducting experiments on 115 listeners from various countries, the study authors concluded that people have the capacity to instantly clock a lie based on this melodic pattern, even if it is spoken in a foreign language.
The researchers set out to discover if prosody – which refers to the rise and fall of a person’s speech – can be used to determine the reliability of a speaker’s discourse. More specifically, they sought to discern if a universal prosodic signature for lying exists, and whether or not this can be detected by listeners.
To investigate, they devised four separate experiments, the first of which required French-speaking participants to listen to hundreds of nonsense words that sounded similar to French words, and rate how honest or deceitful, as well as how certain, they thought the speaker was being. Based on the results, the study authors noted that listeners consistently rated words as both more honest and more certain if they had a falling intonation, were louder at the beginning of the word, and were spoken faster.
In the second experiment, listeners were again presented with an array of spoken pseudo-words but were given some context as to the speaker’s intention. For example, in some instances, they were told that the speaker was playing poker, and had to determine whether they were lying in order to bluff their opponents.
Results were consistent with those of the first experiment, as participants judged speakers to be more honest if their voices adhered to the same falling intonation pattern, and more dishonest if their speech was slower or they put less emphasis on the middle of a word.
The researchers then recruited English and Spanish speakers and found that their responses matched those of the French participants, suggesting that speakers of different languages associate the same prosodic patterns with lying.
Finally, the study authors asked participants to try and recall some of the not-quite words that they had heard. On the whole, listeners were much better at remembering words that had been spoken with dishonest prosody, indicating that this manner of speaking somehow “pops out” against typical speech and naturally attracts more attention.
Based on these findings, the researchers say that this automatic response to prosody represents a “unique auditory adaptation that enables human listeners to quickly detect and react to unreliability during linguistic interactions.”
In other words, if you want to lie convincingly, the first thing you need to do is adjust your prosody.