Speakers unconsciously gesture with their voice, psychologists show

People unconsciously make gestures with their voices, say scientists who report the first evidence of this type of communication.

When people adjust their speech to emphasize points or communicate emotion, researchers assumed it was done intentionally.

On Friday, psychology researchersatthe University of Chicago offered the first evidence of "analogue acoustic expression" — people unconsciously modulating their voices to provide an extra channel of expression for the listener.

To find out if the vocaladjustments were produced even when they were not explicitly needed, research subjects described action they saw on the screen and also read sentences.

In the first experiment, participants looked at a video screen of animated dots and described whether the dots were going up or down.

When they watched dots go up, their pitch rose as they followed the action. When the dots went down, so did their pitch.

Pitch altered

Separately, they read the sentences, "It is going up," or "It is going down," without seeing any action. The pitch changed the same way.

"The results demonstrate that speakers naturally use analog acoustic expression when talking, even when there is no intent to dramatize a description," psychology chair Howard Nusbaum and his colleagues wrote in the August issue of the Journal of Memory and Language.

Another pair of experiments tested if people use the verbal gestures to express information not communicated in their words.

When participants described the movement of a dot from left to right, they spoke faster as the dot moved faster.

When a recording of the speech was played, listeners were able to tell which speakers were describing fast- or slow-moving dots.