What is the appropriate speech rate for a communication robot?

Abstract

This study investigates the influence of a robot's speech rate. In human communication, slow speech is considered boring, speech at normal speed is perceived as credible, and fast speech is perceived as competent. To seek the appropriate speech rate for robots, we test whether these tendencies are replicated in human-robot interaction by conducting an experiment with four rates of speech: fast, normal, moderately slow, and slow. Our experimental results reveal a rather surprising trend. Participants prefer normal and moderately slow speech to fast speech. A robot that provides normal or moderately slow speech is perceived as competent. We further study how context affects this perception. In a situation where the robot and participants talk while walking, we found that slow speech was the most comprehensible. In addition, slow speech is subjectively perceived as good as moderately slow and normal speech.

A transdisciplinary review and framework of consumer interactions with embodied social robots: Design, delegate, and deploy

“…non‐native) accent evokes more positive emotions among consumers toward social robots in a healthcare context (Tamagawa et al., 2011). Furthermore, consumers prefer social robots speaking in a literal, direct language and at a moderate pace (Choi, Liu, et al., 2019; Pan et al., 2015; Shimada & Kanda, 2012). The presence of non‐verbal behavioral patterns (e.g., gestures, gaze, and changing eye color) encourages consumer interactions with social robots (van Pinxteren et al., 2019) and consumer perceptions of hedonic values (e.g., Johnson et al., 2016).…”

Examining the Effects of Communication Features of Educational Robots on Students’ Cognitive Load, Attitudes, and Learning Performance

“…Simonds et al (2006) found that teachers’ slow speech rates reduce their credibility and hinder students’ effective learning. To enable effective and efficient communication between humans and machines, Shimada and Kanda (2012) investigated the appropriate speech rate for robots when providing location information to users. Unlike human-to-human interaction, they found that participants preferred robots with normal or moderately slow speech rates, perceiving them as capable.…”