The Effects of Iconic Gestures and Babble Language on Word Intelligibility in Sentence Context

This study investigated to what extent iconic co-speech gestures help word intelligibility in sentence context in two different linguistic maskers (native vs. foreign). It was hypothesized that sentence recognition improves with the presence of iconic co-speech gestures and with foreign compared to native babble.

Thirty-two native Dutch participants performed a Dutch word recognition task in context in which they were presented with videos in which an actress uttered short Dutch sentences (e.g., Ze begint te openen, "She starts to open"). Participants were presented with a total of six audiovisual conditions: no background noise (i.e., clear condition) without gesture, no background noise with gesture, French babble without gesture, French babble with gesture, Dutch babble without gesture, and Dutch babble with gesture; and they were asked to type down what was said by the Dutch actress. The accurate identification of the action verbs at the end of the target sentences was measured.

The results demonstrated that performance on the task was better in the gesture compared to the nongesture conditions (i.e., gesture enhancement effect). In addition, performance was better in French babble than in Dutch babble.

Listeners benefit from iconic co-speech gestures during communication and from foreign background speech compared to native. These insights into multimodal communication may be valuable to everyone who engages in multimodal communication and especially to a public who often works in public places where competing speech is present in the background.