Split Attention

One of the key principles of instruction is that human brains have limited processing power. If the cognitive load is too high–that is, if we are trying to process multiple sources of information at once–processing is impaired. This principle has implications not only for instruction, but lots of areas in our lives.

Driving is a big one. Lots of people talk on cell phones while driving without incident. This is possible because for experienced drivers, the act of driving is automated. We do it without thinking about it. That leaves lots of cognitive processing power left for engaging in conversation.

Of course, driving is only automatic when it is routine. When something unexpected happens, the act of driving suddenly requires lots of cognitive resources.

Talking on a cell phone is not the same thing as having a conversation with someone in the passenger seat. It requires more concentration. If nothing else, the quality of cell phones is not great, so simply understanding the words and verbal cues takes effort. Thus at the moment of a driving crisis, there are fewer cognitive resources available to deal with the emergency.

That’s not to say I’d outlaw cell phone calls in cars. But it is a trade-off. The more we talk on cell phones the less safe we and the drivers around us are. On the other hand, we’re social and being able to communicate while we drive is useful. Whether the trade-off is acceptable is a philosophical question.

Looking down at the phone to text or otherwise interacting with a screen is just wrong, though. That’s not a cognitive load issue; it’s just a simple question of reaction times.

Anyway, instructional designers tend to be drawn to data collection. I work downtown so the bus is a convenient way to get to work. I started noticing that the number of drivers on the freeway engaged with a screen seemed alarmingly high. I was curious what percentage of drivers were actively engaged with a screen. So I collected data* for a week**.

In reality, the percentage of screen-gazing drivers was much lower than I thought. By the end of the week I had observed 101 drivers on the short stretch of freeway my bus covers on the way to work. Of the drivers, I only saw one actively engaged with a screen, and three who were talking while holding a cell phone to the side of their heads. It was difficult to tell how many drivers were using hands-free devices so I didn’t track that.

My data didn’t support my hypothesis that the early morning is littered with screenward-eyed drivers. Well, perhaps even one percent should be alarming, given the stakes, but it was lower than I was expecting, suggesting I fell victim to confirmation bias. Any drivers I saw looking at cell phones confirmed my perception about the proliferation of screen-encumbered drivers while I ignored the (literally) 99% of drivers work their eyes rooted to the road in front of them.

* Using a nice little app called Counter.
** I hereby cheerfully admit that the flaws in my data collection methodology were both numerous and serious.


3 thoughts on “Split Attention

  1. Ellen

    I recently took the driver refresher training course that folks 55 and over can take (and get 10% off their car insurance for three years). Someting new this time was a video created here in MN about distracted driving. I think it was done by a local TV station, it’s probably available online somewhere. “Ordinary people” drove on a closed course up near St. Cloud, and while they drove they had to meet certain challenges based on their own habits. I guy who says he often writes notes while driving had to listen to and write down a grocery list, for example. Very graphic examples of the results, including the destruction of a cardboard deer.

  2. Pingback: Retraction | Engaged

  3. Pingback: Retraction: Is Cell-Phone Encumbered Driving More Dangerous? | Engaged

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