I was recently taking the Amtrak down from Vermont to New York City when I noticed an interesting contrast, pointed out to me by a chatty fellow passenger.
I generally favor trains over planes when it comes to travel: trains have a drastically smaller carbon footprint, are more reliable, and allow more legroom. But one really annoying strike against trains is that unless they are headed through some pretty rural areas, they don’t filter out cell phone signals. As a person who tries to get as much work done as possible whilst in the captive space of the train, there’s nothing more disruptive to my work process than a person gabbing away on the cell phone.
And so it was that there was this cell phone man, loudly talking to someone else about who knows what. Although it is possible to pull your attention from these kinds of distractions, it takes a lot of effort to put them into the background of your consciousness. I pulled out my trusty earplugs, immersed myself in work, and eventually managed to put his conversation out of my head so I could focus on the article I was reading. Eventually he ended his conversation. At this point he was, in my head, the “obnoxious cell phone man”.
I kept on plugging away and slowly began to realize that this same man’s voice was still there. But this time it was not bothering me at all. In fact, as I worked on trying to decipher a difficult reading passage, the presence of this man’s voice in the background was actually soothing rather than disruptive. The difference? This time, he was talking to another passenger.
Of course this wasn’t the only difference: he was probably speaking in a more harsh manner on the phone as he tried to get his voice heard by a shaky cell signal, and there’s no doubt that face-to-face conversation has a more gentle sound than one end of a phone conversation. The topic might have also had an influence, but I can recall so little of the content of either conversation that I doubt that this really made much difference. No, I think the difference had to do with the nature of the conversation: the incomplete conversation involving a cell phone was much more distracting than the complete conversation involving another passenger.
I have noticed this paradox before: we certainly don’t hush people speaking to each other in public places, but it has become acceptable, sometimes even institutional policy, to hush people on cell phones. Why is this? What makes cell phone conversations different? Shouldn’t a cell phone conversation, which includes only half the conversation and therefore half as many words, be half as annoying? Clearly the answer is “no”, but why?
I believe that the answer lies in the way that our brain works, in particular its ability and propensity to make coherent sense out of incomplete or inscrutable sensory data. This feature of the brain is sometimes called “patternicity”, after our cognitive instinct to form sensory data into meaningful patterns (Michael Shermer is one of my favorite ambassadors for the idea of “patternicity”, which he writes about frequently in Scientific American articles like this one). In this case, it is patternicity that causes cell phone conversations to be more distracting.
When another person is having a cell phone conversation within earshot, your brain tries to make sense out of this conversation. The problem is that you only have one half of the conversation, so that’s when patternicity kicks in and your imaginative brain starts to consider all of the possible things that might be said on the unheard half of the conversation that would explain the half it can hear. What’s interesting about this is that it is by no means a requirement that this be a conscious process. If anything, your brain’s pattern-forming behavior is more pronounced if you allow the cell phone conversation to linger in the background of your consciousness. Filling in this entire missing half of a conversation takes cognitive work, and makes it harder to focus on other tasks. There’s a sort of battle between the conscious desire to focus elsewhere and the unconscious desire to monitor and understand this background conversation, and often the unconscious processes succeed at distracting from conscious desires.
On the other hand, when two people are having a normal two-way conversation in the background, it doesn’t take much work to figure out what is going on. During my train ride the presence of a rather casual conversation behind me actually was soothing. I was half-aware of what was being said, but drifting in and out of conscious recognition of the conversation was actually helpful in maintaining my focus on what I was reading, in the same way that doodling helps one to maintain focus on a lecture.
There are good evolutionary explanations for our pattern-forming cognitive tendencies. After all, every bit of sensory data is in some way an incomplete representation of the world, and our conscious experience of the world is nothing more than a highly-sophisticated simulation of what might be out there based on whatever signals we can gather from what actually is out there. In order to survive, our ancestors had to make life-or-death decisions based on incomplete sensory data. Being able to process distant sounds into comprehensible words or to form an identifying image of a distant but hazy object would have had direct fitness advantages. Trapped in the modern world filled with incomplete sensory data, we just need to teach our brains how to turn the pattern-forming off sometimes.A Major Post, Consciousness, Evolution, Evolutionary Psychology, Human Evolution, Psychological Adaptation