**7. Results**

We obtained the videos and the questionnaire results of 24 participants and analyzed the data. Although there had been 30 participants altogether, one participant could not continue a dialogue because he was not able to hear the robot's voice at all, while the other five participants had halted the dialogue owing to technical problems (e.g., network trouble, program bugs). The two-robot scenario had 13 participants, and one-robot scenario had 11 participants.

We used the Mann–Whitney U test to compare data between the scenarios, and the alpha-level set at 0.05. We used a computer software 'jamovi' [59] for this test.
