Social robots are under rapid growth. One of the important motivations to develop social robots is to assist human in daily life. Recently social robots are already employed in many public spaces for several purposes such as service, education and therapeutic activities. It is considered that multiple media or robots could extend the capabilities of a single robot and offer ways to achieve cooperative work. However, few works have paid attention to different listening styles by humans with the use of multiple robots at the same public place.

In this research, we use two different robots as shown in the above figure. We have been investigating human behaviors towards different styles of interaction by various robots. The developed twin robots, Gemini, talk about some news around the hotel area with each other while using body movement and speech. On the other hand, Palro (Fujisoft Inc.) and Nao (Aldebarran Robotics) are small humanoid robots and designed to make greetings to the hotel guest with body movement and speech. We focus on different ways of providing information via oral conversation by the robots to hotel guests. In Gemini case, the guests overhear robot conversation in a hotel elevator hall. In Parlo and Nao cases, on the other hand, the robot makes greetings to the guest and they listen to the robot’s speech when they come or go out of the hotel.

We assume that listening to the robot is preferred to just overhearing the robots’ conversation although the twin robots talk more than a single robot. We choose a specific time (Saturday late afternoon) when guests may have more time on listening to or overhearing robots during the experiments. The behavior patterns of the guests in the elevator hall are measured to verify how much they are intended to interact with the robot. The hotel has its lobby on the 6th floor. Three elevators on the left side of the lobby are used as common entrances. Another entrance is set on the right side of the lobby which connects with a shopping mall’s 6th floor. All the guests are supposed to appear in the elevators hall, using elevators to go to their rooms. This offers an opportunity to see the robot in a public space.