Regarding backchannels, this point is not up for debate:
Over the last twenty years, Meyer and a host of other researchers have proved again and again that multitasking, at least as our culture has come to know and love and institutionalize it, is a myth. When you think you’re doing two things at once, you’re almost always just switching rapidly between them, leaking a little mental efficiency with every switch. Meyer says that this is because, to put it simply, the brain processes different kinds of information on a variety of separate “channels”—a language channel, a visual channel, an auditory channel, and so on—each of which can process only one stream of information at a time. If you overburden a channel, the brain becomes inefficient and mistake-prone.
I appreciate that people like being able to talk with their neighbors and experience collaborative learning moments whenever they wish, but I appreciate creating the environment necessary for maximum retention and learning more than giving the opportunity for a freedom that, when used without knowledge of cognitive processing, can do more harm than good.
If one person is talking into your left ear while you carry on a different conversation - even if it on the same topic - to someone on your right, you stumble and are a less ineffective communicator. The same is true for reading or typing and listening to someone speak at the same same time. If the human brain (not just "some people") attempts to focus on multiple language sources at the same time, it fails, and it loses nuance and meaning from both point sources that are disseminating the content. And if either of the sources are delivering complex information, forget it, it gets worse. Brains must tune into one language channel at a time, or they are forced to toggle, bleeding a bit of comprehension with every jump. Try listening to two audio recorded lectures of university professors at the same time and you will hear what I mean.
In some circumstances, backchannel discussion can gash the body of the outcome the presenter is working to create. To achieve their outcomes, presenters rely on thousands of purposeful words, gestures, postures, volumes, tones, and visuals that work in sync with each other. Personally, in a presentation where I am there to create understanding on specific content within a short time (like a keynote), it is out of my integrity to create a back channel. Not out of opinion, but rather based on how humans are able to use language.
I am not saying that backchannel conversations cannot be useful or that people cannot learn anything from them. I am saying that when they are used simultaneously while a presenter is delivering, the presenter is being listened to and understood less. (Yes, I know sometimes this can be a good thing.)
Giving opportunities for people to have conversations both short and long, verbally and typed, written and drawn, one-to-one and in small groups, is really valuable for learning. It's just solid collaborative learning theory. But when we put complex and shifting dialogue on screen while someone is presenting complex information we are ignoring the capacity of possible attention in our brain.
If participants want to create a back channel within a presentation on their own, they should feel free. If they do this, it is a signal that one or more of several things are happening:
- The presenter is boring and the audience would rather engage with each other more
- The presenter's specific content is boring and they would rather go parallel on it or talk about something else
- The back channel people need to chat online to get their information load fix
- The back channel people are rude
Point number three is interesting to me right now, because online chat is a cultural phenomenon that has developed only in recent times. When I present in technologically undeveloped areas or with audiences who would rather not be on a backchannel, the audiences are often engaged at a higher level with my specific content.
I know there are presenters who have opposing experiences and will disagree with this. It is just that when I am presenting and ask a question or when someone in the audience makes a comment out loud and there is no backchannel pulling attention away from the conversation I am having in live air, everybody hears it and the response rate is usually higher.
The presenter is a channel. You get more viewers on a channel when you show better content, yes, and also when the other options are fewer. There can be value in limiting options. You can't eat all the food in your refrigerator before some starts to go bad. (Hungry.)
I have seen some presenters use back channels because they love technology so much that they can't see the forest for the luminous screens. They nobly want their audiences to be engaged, so they bring a backchannel into their presentations. But the forest the presenter is missing is an understanding of the brain's capcity to receive and comprehend information. Brains ability to give full attention is a limited bandwidth, not infinite. This is backed up by plenty of recent research on multitasking and processing channels (if you care to search).
Some presenters use back channels as a crutch in the same way that other presenters use their slides as more of a focal point than themselves. In these cases, why not just email the audience the PDFs and save everyone the tedium of your delivery?
Again, before all the All Backchannel All The Time people get defensive, please understand what I am saying: I like online conversations and I like groups of people to have them for learning. But there needs to be discernment in how and when to use them. This discernment comes from understanding how brains process information and what presentation means best support the dynamic's learning outcomes.
We can cry "Times are changing!" but it does not mean that all change is good (or that it just "is"). Some changes can and should be dissected and explored more deeply before jumping on the bandwagon.
We all carry our own belief systems around that make sense to us, and one recent push in the live speaker scenario is that the use of backchannels is modern and about being "with it" technologically. Before blindly accepting this, I encourage all presenters to learn more about how the brain receives and comprehends information and how people learn best in different dynamics. There are times when backchannels can be useful and times when they can hurt the learning process.
In many cases I do use backchannels myself and love or hate them depnding on how and when they are used.