Twitter Sensory-Sensitive Earcons
Earcons can trigger sensory sensitivities with neurodivergent individuals, yet must be accessible for those who prefer to use them.
To make earcons more accessible, we designed and evaluated a set of, what we’re calling, sensory-sensitive earcons through qualitative interviews and concept testing with neurodivergent Twitter users.
By including neurodivergent representation in the design process, we designed guardrails that invited more people in. The earcons shipped in H2 2022 and the work was published at ASSETS 2022 and presented in-person in Athens, Greece.
gm to those who just discovered the new pull to refresh sound on twitter and can’t stop because it’s giving you just enough serotonin to finally start your day@arialxjade
idk about yall but the new twitter sound stimulates my brain just right@SMBKVCH
7-20% of adults identify as neurodivergent—describing those with learning, cognitive, and psychological disabilities. This can result in experiencing sensory sensitivities, which present challenges with sound, which can cause distraction, pain, or discomfort.
Earcons are a critical auditory modality for those who perceive information best through sound. Yet earcons can trigger sensory sensitivities with neurodivergent individuals, causing pain or discomfort and creating barriers to information access.
- Reduce the harm the earcons could cause with our neurodivergent customers
- Ensure that neurodivergent voices are represented throughout the design process
WCAG Criteria for Sound
To ensure sound accessibility, the Web Content Accessibility Guidelines have 3 criteria:
- 1.4.2 Audio Control: Require the ability to turn off sound longer than three seconds
- 1.3.3 Sensory Characteristics: Make sure sound is not the only output modality
- 1.4.7 Low or No Background Audio: Make sure that users can separate speech from background sounds
Earcons Are a Unique Use Case
- They’re often shorter than three seconds
- They have to work for those who require sound to perceive information and have sensory sensitivities, such as individuals with multiple disabilities
- And they’re primary sounds, not background sounds
With a neurodiverse team, I conducted a generative research study on Twitter using semi-structured interviews with 9 neurodivergent Twitter users to understand how to design sensory-sensitive earcons.
I then created codes, supported codes with data, grouped codes into themes. Each theme represented a criterion for a sensory-sensitive earcon.
I used the themes to create mapped guidelines to avoid sensory sensitivities with each theme. I then provided our sound vendor, Listen, with the guidelines generated by our study to produce sound concepts.
Working with the sound vendor, I ensured the sound design guidelines were applied correctly, while meeting Twitter brand standards. I provided detailed feedback over 4 iterations before concept testing.
Crafting Final Earcons
To further craft the concepts, I synthesized feedback from concept testing with 7 neurodivergent customers to ensure their preferences were included: 1) remove repetitive notes; 2) take intensity and frequency down to avoid high-pitched notes; 3) smooth out the shape of the sound envelope.
Through partnership with a quantitative researcher, I invited customers to vote for the final sounds used on Twitter’s consumer product, since Twitter belongs to the people who use it.
Generative Research Methods
We recruited participants with a screener survey sent to 22,439 individuals to find Twitter users between the ages of 18-65, asking them their age, gender, whether they self-identified as neurodivergent, and if they had used Twitter in the past month. We received 201 qualified responses before identifying nine Twitter users (1 nonbinary, 1 trans male, 3 female, 4 male; ages 18-35) who self-identified as neurodivergent and had experience using audio notifications on their mobile devices.
With informed consent, we conducted qualitative, semi-structured interviews via teleconferencing software. We recorded video, transcribed the audio, and stored the data on a secure cloud server. The first and second author reviewed the data and performed a thematic analysis.
- Do you keep sound notifications turned on or off? Why?
- What do you think makes a sound annoying?
- What are some types of sounds you would like to see less of in apps?
- Tell me about a time when you had a bad experience with sound notifications.
- What sound notifications do you like, or even love?
- Was there ever a sound notification that was fine at first, but increasingly bothered you over time? Can you describe that sound?
6 Key Sensory-Sensitive Earcon Themes
Many (5 participants) described challenges with duration. They told us that “ding” sounds were bothersome because they would linger, while shorter sounds were more pleasant. When asked to provide specific duration guidance, they said that shorter than one second was ideal.
6 participants reported sensory sensitivities with repetition. They told us that hearing a sound multiple times annoyed them and was unnecessary for understanding an earcon.
Almost all (8 participants) reported issues with the shape of the sound envelope. They told us that sudden earcons annoyed them, while gentler earcons were appreciated.
Intensity & Frequency
Almost all (8 participants) highlighted issues with intensity and frequency. High-pitched or loud notes caused discomfort with participants, even if they had their computing device volume settings turned down.
Most (6 participants) detailed their views with familiarity. They explained that recognizable sounds could be more clearly mapped to an action.
Most (6 participants) reported challenges with purpose. They said that excessive sound that did not identify anything specific could feel overwhelming.
Keep duration to one second or less
Minimize wavelength space between repetitive notes to avoid percussive sounds
Use a smooth sound envelope, with a slow attack and decay, and no sustain or release
Intensity & Frequency
Keep intensity mid-range (~ 40-50 dB) and the frequency close to the human voice (~ 1k Hz)
Use recognizable, skeuomorphic sounds
Only use earcons for confirming something has happened or indicating an error
My feedback for the sound vendor was to remove the series of repetitive notes during the “refresh” and to make it sound more familiar and skeuomorphic.
My feedback was to reduce the intensity and frequency to avoid high-pitched notes and to smooth out the sound envelope so it was less tactile and jarring sounding.
My feedback was to reduce the intensity and frequency and to soften the shape of the sharp sound envelope to avoid discomfort.
Crafting Final Earcons
Sound Envelope Shape
We surveyed over 2,700 Twitter customers, who were both neurodivergent and neurotypical. I asked respondents to vote between two options for pull-to-refresh, notification, and send tweet.
Curb Cut Effect
Neurodivergent and neurotypical customers all voted for the exact same sounds in every category, producing the Curb Cut Effect. The Curb Cut Effect is rooted in the disability justice movement, when advocates requested ramps on the corners of sidewalks for wheelchair users. But then everyone started using them: people with strollers, skateboards, and rolling suitcases.