Bigger (Gesture) Isn't Always Better

The literature suggests that familiarity and rapport are enhanced by larger, more extraverted gestures. However, the sizes of the increases in amplitude have not been reported. We sought to determine whether this relationship holds true for interaction between humans and embodied conversational agents. To this end, we conducted an experiment in which we increased gesture amplitude, with quantification of the gesture sizes. We hypothesized that rapport would be increased in the larger-gesture condition. However, our results were exactly the opposite: Rapport fell significantly in the larger-gesture condition. This means that larger may not always be better for building human-agent rapport. Our unexpected results may be because our agent’s gestures were simply too big, odd, awkward, or strange, or because of a statistical anomaly.