Information Theory Applied (Loosely) to Cell Phones, Ham Radio and General Aviation


If talking on the cellphone in the car is so bad, why are ham radio operators exempt and what about pilots?


There’s an article in the current MIT Technology Review, called “The Paradox of Wearable Technologies,” written by Don Norman. He describes himself as, “a cognitive science professor (UC San Diego, Northwestern) turned executive (Apple vice president) turned designer (IDEO Fellow), and author of 20 books, including Living with Complexity and The Design of Everyday Things.”  The article was triggered by Google Glass, and it’s about staying alive (or not) while you’re distracted by your personal technology.

All of us have different capabilities for functioning in the presence of distractions. At one end of the spectrum is the classic being “unable to walk and chew gum simultaneously.” The other is well represented by Norman’s friend and associate, Thad Starner, who was a technical advisor to Google Glass.

Starner confessed to Norman that he was “very bad at multitasking.” But he said that what he does when he attends a lecture with Google Glass is to, “put the physical focus of the display at the depth of the blackboard.”  Then since he has a special keyboard he keeps in his pocket, he could, “both pay attention and take good notes.” This was, Norman says, “far better than with paper and pencil, when his attention had to shift from notebook to blackboard.

“The result is that during any interaction, he is far more focused and attentive than many of my non-computer-wearing colleagues: the act of taking notes forces him to concentrate upon the content of the interaction. Moreover, he has records of his interactions, allowing him to review what took place.”


Distractions and Concentration

The article made me think about human communication in the face of distractions.  Even if I had a one-handed keyboard that I could type on in my pocket, I doubt whether it would work for me. I get distracted easily.  In fact, when I interview somebody at a tech company about a new product or technology, I need all my wits just to come up with follow-up questions. (What I do, is, I either rely on memory, nudged by the guy’s Power-Point foils, or, if I’m talking to a CTO or other exec I need to quote accurately, I record the session on my iPad and send the audio file to an outfit in India that transcribes it.) 

But getting back to everyday life, what this leads up to is the broad question of the distractions we create for ourselves with mobile technology.  Politicians and the news media these days tend to focus on cell phone use and texting in cars.  Both are acknowledged as bad, and a lot of people, myself included, would say that even hands-free phone conversations are too distracting for people driving in traffic.

My dilemma is, how do I reconcile that attitude with two of my hobbies: ham radio and flying?  Here in California, talking on a cell phone in any mode except hands-free (actually, touching it at all) is grounds for a big fine . . . but amateur radio operators using their two-way radio gear, are explicitly exempt.  And general-aviation pilots (like me before my FAA medical went away) couldn’t fly in most populated areas without a two-way radio.  What’s with that?  Are hams and pilots more mentally adept than the rest of humanity?

Not that I’ve noticed, so let me propose an alternative idea.  Let me call it the Shannon Effect, after the father of Information Theory:  The lower the information content, the less distracting the communication.

Take ham radio communications.  Unless you’re passing information in a disaster (or operating in a contest), one ham QSO is remarkably like every other QSO. You don’t need to take notes.  In fact, the next time you talk to this guy or that woman, the content of the conversation is going to be remarkably like the last time. The reason the legislature gave hams the exemption is because of the potential need for hams in emergencies, and you know what? We practice emergency drills just so that, in a disaster, the information we pass along is going to seem just as routine as possible.

Something similar happens in aviation. The information content of the messages is kept very low through the use of common phraseology.

“San Carlos Tower, Piper 9749Whiskey, Crystal Springs, with Juliet.”

“49Whiskey, cross mid-field at or above 1200, enter right traffic for three-zero.”

I repeat the instruction. Everybody on the frequency knows where I am and what I’m going to do.

Contrast that with cellular calls.  Every one is different.  You’ve got two people going back and forth, arguing their way through all possible options for something that’s got to happen just so, at some specific time, that involves countless decisions to be offered and rejected or accepted.  The information content is enormous and volatile. Do you really want somebody merging onto a freeway when their brain cells are that preoccupied?

Discuss this Blog Entry 22

on Jul 27, 2013

congratulations, Don, you have self-invented upon well-known principles of human attention. At low levels of activity, people can multi-task quite well. The problems occur when resource limits are reached. Both driving and flying have long periods of remarkably low information requirements. One of my friends studied drivers on a highway forced to wear occluding goggles: they could drive on straight highways with only a brief glance every 5 or so seconds. On turns, they had to sample more frequently. With traffic -- well, he didn't test in traffic for obvious reasons. But in busy situations, information requirements can be high: That is why the FAA requires a "clean cockpit" environment for commercial aviation at takeoff and landing. That is why checklists are good ideas: errors frequently occur after an interruption.

(See my website at or my book Design of Everyday Things ofr more. )

Your comment reminded me that we now have a zillion highly specialized fields, so that people with expertise in one seldom even know about the existence of the others: too bad -- if we could share the knowledge better, we could make better progress.

Don Norman

on Jul 31, 2013

An additional reason why ham radio puts lower demands on our ability to multitask than cell phones is that it is half duplex. Only one person can talk at a time.

on Aug 4, 2013

Not to be unduly argumentative, but in my experience, cellphone communications have always been half duplex. That, along with the latency inherent in the technology, makes it practically unbearable for me to use. I have given up my cell phone entirely. And I suspect that these factors are also at least partially responsible for text communications becoming so popular

And for what it's worth, it is possible to have full duplex ham radio communications.

on Aug 2, 2013

"At low levels of activity, people can multi-task quite well" well said! Applies to computers too :-) The scheduling theory says so!

on Aug 5, 2013

Haha, with Shannon's Law, information capacity was the dependent variable. Now, with Shannon's effect, it is the independent variable directly proportional to the degree of how distracting the communications medium is.
Blinding/blocking one side of your vision leaves you with a large blind spot that can be a magnet for accident. One time I had my left eye closed and suddenly a speeding taxi swooshed right in front of me from the left and I didn't even see it coming.

on Aug 5, 2013

I read a while back that one other aspect of "mobile" communication vs. in-person communication is that when you have a conversation with a person who is physically present in a vehicle, they are aware of your status as a driver and can compensate by not talking, or at least beaing aware of situations that require more attention on your part. "Remote" listeners don't have that situational awareness and may add to the driver's stress by asking questions like, "How come you stopped talking? Is everything OK? You are just like your father - always clamming up when things get serious, blah, blah, blah..." when, in fact, a car has just had a flat tire in front of you and is swerving all over the road, and your attention is focused on avoiding an accident.
I have found that even in-person conversations can be very distracting when driving in city traffic - on the freeway is much easier, regardless of the communications mode. Also, I am also a ham, and find that trying to use an HT is generally too distracting while driving, unless the information content is low, as you suggest.

on Aug 5, 2013

Anyone that thinks a cell phone is full-duplex either isn't listening very carefully ... or doesn't know what the term means. I'm with HamGuy, they drive me nuts! I feel like saying "over" after every utterance. I'll hold onto my copper land-line as long as possible for the same reason (and also not wanting to put all my communication "eggs" in one basket). Seems to me, with increasing bandwidth available to cell phones, that someone would actually work towards full-duplex. But I guess the public, young ones specifically, have been "dumbed down" to think that half-duplex is "normal" ... as normal as texting between folks at the same table and MP3 files being "CD quality"!! Ah, technology ... as for "multi-tasking", I think a better term would be "attention multiplexing" (time sharing). As shown by Myth Busters and others, just carrying on a conversation (never mind what you're holding, pressing, or staring at) is just as debilitating to driving alertness as having a few drinks. If we let them, handheld devices will become the downfall not only of real social interaction but public safety as well. Personally, I actually ENJOY periods when I'm "disconnected".

on Aug 5, 2013

Very interesting and useful point. However, as noted at the beginning, there is a lot of variation in people. Some people absolutely have no business driving and talking (on anything) at the same time. Others can manage their focus quite well. I have no fears about talking and driving, but will defer the conversation or pull off the road if the information density gets too high Fortunately, Colorado has chosen a less rigid approach. It is clearly necessary to keep dangerous situations off the road, but it is a challenge to balance that with allowing people to do what they can do safely. Add to the fact that the cell phone is so ubiqutous. It increases the number of people involved who don't know their own capabilty and make bad judgement calls. It is also possible that there is a correlation between technical expertise and ability to make good judgements. It is possible that ham radio operators (of which I am also one) are safer with a microphone than the general population. Same may go for pilots (which I am not)--not just anyone can enter either of those fields.

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