Interaction Situation
Robot and user are engaged in interaction. The user provided some speech input that could not be interpreted by the robot, which is indicated by the robot.
Solution
Let the robot express that:
That the processing of the user input failed, can be best indicated through light. We recommend to use a reddish, orange or pinkish color and a relatively fast blinking light pattern. As an alternative, an appropriate sound could be used. Energetic sound compositions are especially attention grabbing.
Related patterns:
Needed by: Not understanding
Opposed patterns: Loading Animation
Examples
Rationale
Red color is commonly associated with malfunctioning technical devices. For example, machines on the shopfloor indicate critical events through a red blinking light. The color red has an demanding and stimulating effect. Blinking light is especially attention grabbing. The same design pattern is also used by other devices such as loudspeakers and music players that start blinking when the connection fails. Other devices or apps use sound for the same purpose. For example, the skype application plays a specific sound when the connection failed or the call is not answered.
References and further readings:
- Baraka, K., & Veloso, M. M. (2018). Mobile service robot state revealing through expressive lights: Formalism, design, and evaluation. International Journal of Social Robotics, 10(1), 65–92. https://doi.org/10.1007/s12369-017-0431-x
- Choi, Y., Kim, J., Pan, P., & Jeung, J. (2007, September). The considerable elements of the emotion expression using lights in apparel types. In Proceedings of the 4th international conference on mobile technology, applications, and systems and the 1st international symposium on Computer human interaction in mobile technology(pp. 662–666). https://doi.org/10.1145/1378063.1378175
- Sounds for indicating critical events: https://files.design/sounds
- Social media UI sound collections: https://uisounds.prototypr.io/