  In human interaction, gestures serve various functions such as marking speech
rhythm, highlighting key elements, and supplementing information. These
gestures are also observed in explanatory contexts. However, the impact of
gestures on explanations provided by virtual agents remains underexplored. A
user study was carried out to investigate how different types of gestures
influence perceived interaction quality and listener understanding. This study
addresses the effect of gestures in explanation by developing an embodied
virtual explainer integrating both beat gestures and iconic gestures to enhance
its automatically generated verbal explanations. Our model combines beat
gestures generated by a learned speech-driven synthesis module with manually
captured iconic gestures, supporting the agent's verbal expressions about the
board game Quarto! as an explanation scenario. Findings indicate that neither
the use of iconic gestures alone nor their combination with beat gestures
outperforms the baseline or beat-only conditions in terms of understanding.
Nonetheless, compared to prior research, the embodied agent significantly
enhances understanding.
