Sound as implicit influence on human-robot interactions

Dylan Moore, Stanford University


People anthropomorphize servomotor sounds [1]


"like a robot I can trust"

"like a robot I can trust"

"the machine is working very hard"

"the machine is working very hard"

"the sound of robot nightmares"

"the sound of robot nightmares"

In an online study, participants evaluated sound characteristics through pairwise comparisons. Participants anthropomorphized the recordings (below) and their comparisons produced quantitative representations of the sounds along seven subjective dimensions.

[1] Moore, D., Tennent, H., Martelaro, N., & Ju, W. (2017, March). Making Noise Intentional: A Study of Servo Sound Perception. Human Robot Interaction 2017. Vienna, Austria. [link]

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Changing motor sound quality influences the evaluation of a robot arm [2]

In an online video study, participants rated a robotic arm along several dimensions including trust and competence. Motor sounds were overlaid onto the video to match the arm’s movement. 

When the robot worked alone (functional context), high-end and low-end sounds reduced perceptions of trust and competence compared to no sound. However seeing the robot interacting with a human (social context) mitigated some of the sounds’ negative effects. 


[2] Tennent, H., Moore, D., Jung, M., & Ju, W. (2017, August). Good Vibrations: How Consequential Sounds Affect Perception of Robotic Arms. Ro-Man 2017, Lisbon, Portugal.


Changing motor sound pitch influences the perceived speed of a roboT

In another online video study, participants evaluated a small robot crossing paths with a pedestrian. Motor sounds were overlaid onto the video to match the robot’s movement. 

3rd person rising sound

1st person falling sound

Even though the robot moved at a constant speed, for about a third of participants, a falling motor pitch made the robot seem to slow down, and a rising motor pitch made the robot seem to speed up. There were no differences in evaluation of the robot’s characteristics such as likability and dominance in the interaction. 

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Future Work

Can robots communicate with pedestrians through motor sounds? 

I continue to explore how small pedestrian robots use sound (in combination with physical gestures) to communicate with pedestrians. I will apply these ndings to design interactions between pedestrians and autonomous vehicles.