We all tend to gesture when we speak. We make hand gestures whether we are explaining something to someone at home or on the phone, without anyone seeing us. We do so consciously for some pre-defined purpose, and even unconsciously.

Theoretical models for the production of speech and gestures have proposed that gestures help to plan and conceptualize what we mean, regardless of whether the listener can see us or not. But the exact relationship between speech and gesture is not yet fully known. Since gestures are so ubiquitous when we speak, what if speakers are prevented from making gestures when they speak? Does the inability to gesture affect speech in any way? Does speech become less fluent or less emphatic?

These are some of the questions that researchers at the Department of Linguistic and Literary Studies (DiSLL) of the University of Padua in Italy, together with the Prosody Study Group (GrEP) at the UPF Department of Translation and Language Sciences, led by ICREA professor Pilar Prieto have recently attempted to answer by publishing the results of the study in the journal Speech Communication.

“In our research, we were interested in studying the gesturing that accompanies speech, particularly the gestures that people make with their hands when speaking”, comments Alice Cravotta, principal investigator of the study who did part of her doctoral thesis during an Erasmus stay at the UPF laboratory. “We wanted to understand the importance of these gestures for communication and saw that they needed investigating with very important variables for the study of prosody (the branch of linguistics that analyses elements of oral expression such as pitch, tone and intonation)”.

The general belief is that gestures help us to be clearer. Cravotta gives us an example: “Imagine you have your hands tied behind your back and you have to give instructions on how to get to a place. We think it’s a little harder than explaining it with your hands free. To find out, we hypothesize that restraining people from making gestures would affect their ability to speak, to remember or retrieve the right words at the right time, to plan what they want to say, and to put the right emphasis on what they are saying”.

The researchers recruited 20 female volunteers between the ages of 20 and 30. “The reason for studying this only with women was to standardize voice study acoustic variables, but clearly the same study can be conducted with a mixed group”, Cravotta explains.

The researcher showed a comic strip to the participants and then asked them to describe it to another person. Under the control condition they were simply asked to explain the comic strips without any specific instructions on gestures and under the experimental condition they were asked to put their hands under their legs as they described it, so that they could not make hand gestures. They video-recorded all the interviews and analysed their discourse in audio, studying variables such as the number of words, the speed of speech (syllables per second), the length of each narrative (in seconds), the pauses, self-corrections, repetitions, insertions, or interruptions, and finally the tone and intensity of the voice.

“We found that restraining gestures did not affect the fluency or acoustic characteristics of speech or the production of speech, which other studies have also found”

“We found that restraining gestures did not affect the fluency or acoustic characteristics of speech or the production of speech, which other studies have also found”, Cravotta  explains. “This is surprising since some studies have shown that when the production of gestures is encouraged, however, it helps people in lots of ways such as learning, solving problems (mathematical), improving memory, and so on”.

However, when analysing the data eliminating the group of participants that least gesticulated under the control condition, the researchers found that under the experimental condition where gesture production was prevented, participants produced speech with different prosodic features from natural speech with gestures. “We saw that it can have different effects depending on the extent to which these people resort to gestures when they speak. If people gesture less under normal conditions, they need fewer gestures to communicate properly”, she adds.

The next step is to study in greater depth the individual differences in the ways people use gestures. “There is no doubt that there are cultural differences in the use of gestures, some people gesticulate more than others and even many vary depending on the attitude of the speaker and the context. Many studies agree on the key importance of gestures in general and how strong the connection is between speech and gestures both cognitively and linguistically. Studying the extent to which this applies to individuals with different dispositions and cognitive characteristics serves to better understand the underlying mechanisms and causes of this complex interaction”.

Reference article:

A. Cravotta, et al. Exploring the effects of restraining the use of gestures on narrative speech. Speech Communication 135 (2021) 25-36  https://doi.org/10.1016/j.specom.2021.09.005