2010 年 25 巻 6 号 p. 733-741
We describe artificial subtle expressions (ASEs) as intuitive notification methodology for artificial agents especially in order to convey their internal states for users. We prepared two types of audio ASEs; one is a flat artificial sound (flat ASE), and the other is a decreasing sound (decreasing ASE). These two ASEs were played after a robot made a suggestion to the users. Specifically, we expected that the decreasing ASE will inform users of the robot's lower confidence about the suggestions. We then conducted a simple experiment to observe whether the participants accepted or rejected the robot's suggestion in terms of the ASEs. The result showed that they accepted the robot's suggestion when the flat ASE was used, while they rejected it when the decreasing ASE was used. Therefore, we found that the ASEs succeeded in conveying the robot's internal state to the users accurately and intuitively.