Interaction Situation
The user has carried out an action or made an input and robot has to evaluate/ judge it. The outcome of the action/ input is not as expected/ incorrect and the robot has to communicate this to the user.
Solution
Let the robot express that:
To provide feedback that something was categorized by the robot as incorrect, a widely known, unambiguous signal should be used. This can be either an expressive red light signal, an negative/ disapproving sound (descending series of tones) or – if the robot has some kind of display – a meaningful symbol (such as a cross or thumbs-down).
Related patterns:
Needed by: Empathic negative feedback, Gloating negative feedback
Opposed patterns: Indication of Correctness
Rationale
In daily life, green light signals are commonly used to communicate incorrectness, disapproval or warning. For example, traffic lights turn red when passing the street is not safe. Many technical devices show a green light when turned on and ready to use.
In human speech and sound design, disapprovement and negative feedback is often indicated by a descending series of tones. In daily life, such sounds can be found, for example, for confirming the reception of a message or correctness of an answer in quiz game applications.
References and further readings:
- Google Material Design Library: https://material.io/design/sound/sound-attributes.html#tonality
- Sounds for indicating errors: https://files.design/sounds
- Social media UI sound collections: https://uisounds.prototypr.io/