How the “Leaf Blower Problem” highlights the importance of helping our users find common ground in hybrid work
By Brent Hecht (opens in new tab), Jaime Teevan (opens in new tab), and Abi Sellen (opens in new tab)
In the past year, leaf blowers, barking dogs, and fussy children have all become staples of our online meetings. This is a case where technology has seemed to come to the rescue, and one of the more impressive AI features in Teams and online meeting software is background noise reduction (opens in new tab). Noise reduction capabilities, however, have become so good that they have introduced a new issue, which we call the “Leaf Blower Problem.” And the Leaf Blower Problem is about more than just leaf blowers (or dogs or children): it highlights the importance of designing for “common ground”, one of the more critical design challenges in developing technologies for remote and hybrid work.
Put simply, the Leaf Blower Problem occurs during online meetings when there is a very loud background noise for one participant and a background noise reduction system successfully eliminates that noise for the other participants. Problem solved, right? Nope! While the noise reduction minimizes distraction for other participants, it does not do so for the person collocated with loud noise. This creates a gap in the shared experience of the participants. The people who can’t hear the noise may wonder why the person who can is distracted or not paying attention. And the person who can hear the noise may not know that the noise has been eliminated for the others, causing that person to apologize into the silence for “All that noise that’s coming through!”
The Leaf Blower Problem is a new manifestation of an old problem in human-centered AI and UX design. Specifically, the problem is a version of a grounding error, a well-known issue among the class of those in human-centered AI and UX trained in psycholinguistics. Grounding errors get in the way of a key requirement for effective conversations: common ground.
Prof. Darren Gergle at Northwestern University and his colleagues provide a good summary of the role of common ground in communication.
“Successful communication relies on a foundation of mutual knowledge or common ground. Conversational grounding is the process of establishing that common ground. Speakers form utterances based on an expectation of what a listener is likely to know and then monitor that the utterances are understood, whereas listeners have a responsibility to demonstrate their level of understanding.” (Gergle et al. 2013 (opens in new tab))
Through the lens of Gergle’s description, we can understand a ground error as something that prevents all the people in a conversation from having the same understanding of what’s going on, and – critically – knowing that they all have that same understanding. In other words, a grounding error is something that negatively affects a group’s ability to achieve common ground. Without common ground, significant miscommunications, team-wide failures, and even serious conflict can occur, in addition to other problems like the actor-observer effect (opens in new tab).
Some examples are illustrative. If Maria, a programmer, uses an acronym like “RESTful” with Nell, who is not a programmer, and Nell doesn’t ask for clarification, a grounding error has occurred. Maria and Nell don’t have the same understanding of the key entity being discussed, and they don’t know they don’t have that same understanding. The conversation may be derailed until common ground around the entity Maria is talking about can be established. A related example comes from AI systems that translate between languages: if Maria says the word “red”, but an AI system translates that to “purple” in Chinese, it will be very difficult for all participants in the conversation to have the same understanding of what’s being discussed and know that each is having the same understanding. The conversation will be disrupted until all participants are able to reestablish a common ground around the color that Maria is discussing.
The exact same dynamic occurs in the Leaf Blower Problem. Maria might hear a horrendously loud noise, but Maria doesn’t know if the others in the meeting hear that noise as well. In other words, Maria doesn’t know if the noise is common ground. Similarly, if the noise is not audible to Maria’s colleagues, Maria’s colleagues do not know why Maria might be acting distracted; the reason Maria is acting distracted is another piece of information that is not the common ground of the meeting. The desire to re-establish common ground in any conversation is the reason why Maria feels the urge to explain that she can hear a leaf blower (or crying baby, or vacuum cleaner…) and to tell folks that is why she is feeling distracted.
Grounding errors that are caused by technology can usually be mitigated or addressed with better technology design that prioritizes common ground. How can meeting software support the participants in a call in achieving common ground in the presence of background noise reduction? One approach might be to use an icon similar to the mute indicator to let others on a call know that one person is experiencing significant background noise, and thus may be distracted. Another design might detect whether a loud background sound is present on the other ends of a call and provide a pop-up notifying the person who is experiencing the background sound, e.g., “Noise reduction successfully eliminated the background noise you are experiencing” (or the inverse). This could appear in a banner at the top of the screen similar to recording notifications.
More generally, as we increasingly build systems for hybrid settings, we have to ensure that we minimize the amount of time it takes for all participants to successfully achieve common ground. This means either designing common ground into meeting software (by making sure, for example, visual and auditory experiences are shared). When that is not possible – e.g., when there is a leaf blower present – every effort should be made to scaffold the grounding process so that each participant is aware of the other’s situation.
People will have many other grounding challenges as we enter a world of hybrid work. Some examples include:
- We already see people wanting to know if others can see a shared document after they’ve shared it. The common “Can you see my screen?” utterance emerges out of the desire to ensure common ground in a conversation.
- Common ground is undermined in the default “Brady Bunch” video call layout because the layout is different for each person. An obvious manifestation of this occurs when we “go around the table” to introduce people and there is no shared ordering to allow us all to know who should go next. Likewise, pointing or head turning towards someone doesn’t work (unlike in the opening credits of the Brady Bunch) due to the lack of this mutually shared frame of reference. This is one reason why Together Mode in Teams has benefits: everyone knows that everyone else see the same view.
- When a person sends an emoji on Teams or Slack in Windows and it shows up on Teams or Slack in iOS, the emoji will be rendered differently (i.e. using Apple emoji instead of Microsoft emoji). This can create grounding challenges similar to the machine translation example above (see Miller et al. 2016).
- In hybrid settings, collocated meeting participants will struggle to know if remote participants have heard side conversations, and the inverse is true with parallel chat. This also extends to shared artifacts: remote people will often not see or understand how in-room participants are viewing shared whiteboards, documents, or other objects, including gestures around them.
- Grounding is a key reason why self-view has become a mandatory feature for video calls. People want to see what others see when they look at their box. In hybrid work, this will be more difficult for collocated participants.
Grounding covers a huge range of issues from “in-the-moment” shared understanding, through to shared history and knowledge, to shared culture. All of this is fundamental to our ability to communicate and collaborate together. Those who are particularly interested in learning more about grounding in communication can read Prof. Herb Clark’s foundational book (opens in new tab) on the topic. If you’d like a quicker summary, Gergle and colleagues’ 2013 paper on grounding in video calls (opens in new tab) (read to the end of Section 2) and Miller et al.’s 2017 paper on grounding and emoji (opens in new tab) (read to the end of the introduction) are great places to start.