Time Figure 1: Robot performs conversational fillers to buy time That one! Oh, this one. OK, I'll bring it later.etto... This paper reports a study about system response time (SRT) in communication robots that utilize human-like social features, such as anthropomorphic appearance and conversation in natural language. Our research purpose established a design guideline for SRT in communication robots. The first experiment observed user preferences toward different SRTs in interaction with a robot. In other existing user interfaces, faster response is usually preferred. In contrast, our experimental result indicated that user preference for SRT in a communication robot is highest at one second, and user preference ratings level off at two seconds.However, a robot cannot always respond in such a short time as one or two seconds. Thus, the important question is "What should a robot do if it cannot respond quickly enough?" The second experiment tested the effectiveness of a conversational filler: behavior to notify listeners that the robot is going to respond. In Japanese "etto" is used to buy time to think and resembles "well..." and "uh..." In English. We used the same strategy in a communication robot to shadow system response time. Our results indicated that using a conversational filler by the robot moderated the user's impression toward a long SRT. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. This aspect contrasts with a traditional human interface, since SRTs less than a second are preferred in user interfaces [7][8] [9].

During conversations, speakers establish their and others' participant roles (who participates in the conversation and in what capacity)-or "footing" as termed by Goffman-using gaze cues. In this paper, we study how a robot can establish the participant roles of its conversational partners using these cues. We designed a set of gaze behaviors for Robovie to signal three kinds of participant roles: addressee, bystander, and overhearer. We evaluated our design in a controlled laboratory experiment with 72 subjects in 36 trials. In three conditions, the robot signaled to two subjects, only by means of gaze, the roles of (1) two addressees, (2) an addressee and a bystander, or (3) an addressee and an overhearer. Behavioral measures showed that subjects' participation behavior conformed to the roles that the robot communicated to them. In subjective evaluations, significant differences were observed in feelings of groupness between addressees and others and liking between overhearers and others. Participation in the conversation did not affect task performancemeasured by recall of information presented by the robot-but affected subjects' ratings of how much they attended to the task.While Aiko and Robovie talk about how to get to the Muji store, another shopper, Yukio, approaches Robovie's booth. Yukio wants to get a program of this month's shows at the amphitheater. When Yukio approaches the information booth, Robovie acknowledges Yukio's presence with a short glance, but turns back to Aiko, signaling to Yukio that he has to wait until its conversation with Aiko is over and to Aiko that it is attending to her.This scenario differs with the addition of a non-participant [11] into the social situation who is playing the role of a bystander [19].After Robovie's conversation with Yukio is over, a couple, Katsu and Mari, approach the booth, inquiring about Korean restaurants. Robovie asks the couple a few questions on their dining preferences and leads them to a suitable restaurant.

This paper reports a study about system response time (SRT) in communication robots that utilize human-like social features, such as anthropomorphic appearance and conversation in natural language. Our research purpose is to establish SRT design guidelines in communication robots. The first experiment observed user preferences toward different SRTs in interactions with a robot which indicated that user SRT preferences in a communication robot are peak at one-second SRT.Based on the results of the first experiment, we conducted two further SRT investigations. One is for delaying strategy and we propose conversational filler which is a behavior that notifies listeners that the robot intends to respond. The other is for habituation effect to see the trend of the first T. Shiwa ( ) · T. Kanda · M. Imai · H. Ishiguro · N. Hagita experiment's result will remain or not when using robots in daily life. In both investigations, we addressed how the delaying strategy and the habituation effect affect on SRT preferences.

This paper reports a study about system response time (SRT) in communication robots that utilize human-like social features, such as anthropomorphic appearance and conversation in natural language. Our research purpose established a design guideline for SRT in communication robots. The first experiment observed user preferences toward different SRTs in interaction with a robot. In other existing user interfaces, faster response is usually preferred. In contrast, our experimental result indicated that user preference for SRT in a communication robot is highest at one second, and user preference ratings level off at two seconds. However, a robot cannot always respond in such a short time as one or two seconds. Thus, the important question is "What should a robot do if it cannot respond quickly enough?" The second experiment tested the effectiveness of a conversational filler: behavior to notify listeners that the robot is going to respond. We used the same strategy in a communication robot to shadow system response time. Our results indicated that using a conversational filler by the robot moderated the user's impression toward a long SRT. Put it all together, we obtained a) users' impressions toward the robot are unchanged until one second SRT, b) the robot should react within two seconds SRT, and c) use of conversational fillers are effective to let the users to wait from these two experiments.