Your brain is busiest while driving

Saturday, April 11, 2015 | 2 a.m.

The process of driving requires your brain to perform many tasks simultaneously: operating the vehicle; judging spatial relationships; deciding when to brake, accelerate or change lanes; paying attention, scanning the roadway and anticipating the actions of other drivers, just to name a few.

With practice, most of us get comfortable performing these tasks, often failing to realize that what has come to feel like “second nature” still requires a lot of complex processing within the brain. That’s where the problem arises: We don’t perceive the cognitive demands of driving and start introducing other tasks into the equation. One of the most common, and most dangerous, is cell phone use.

Your brain can’t really multitask

Whether you consider yourself a good multitasker or a bad multitasker, the truth is the brain doesn’t truly multitask at all. When we take on multiple activities at once, the brain slyly switches its focus back and forth between one task and the other. This happens so rapidly, it’s easy to think you’re multitasking, when in reality, your brain is performing the tasks sequentially, one at a time.

As the brain flip-flops its point of focus, details of each task get lost in the shuffle. Often, you don’t even realize what details are lost, because within your consciousness, they never existed at all. Some lost details may not be consequential, but when driving is involved, missing a detail could be the difference between getting home safely or causing a life-altering crash.

Demanding that your brain switch its focus back and forth between the road and your phone can slow reaction time drastically. As your brain is flooded with alternating signals, you’re unable to react quickly to unexpected hazards. Switching your attention may require only a fraction of a second, but that’s a fraction you cannot spare while driving. When a driver needs to react immediately, a fraction of a second could cause a crash.

How distracting are Handheld devices, hands-free devices and conversations with passengers?

Most states have laws banning handheld phones and texting, while hands-free phone devices are a legal alternative. However, hands-free devices are not safe. While they alleviate manual and visual distraction risks, they still involve a harmful cognitive distraction. There is little evidence to indicate hands-free phones produce quantifiably safer driving outcomes. Talking on a phone by any method is dangerous.

Some studies have shown that having any kind of conversation while driving, including talking to passengers, is dangerous because the conversation itself prevents a range of cognitive processing to take place.

There are other studies that assert cell phone conversations are more dangerous than conversations with passengers. While on the phone, you may feel more pressure to respond immediately, even when driving in a challenging environment, because the person you’re talking to is unaware of the attention-demanding conditions. A passenger, however, often will scan and monitor the driving environment and know to suppress conversation when needed.

Distractions can narrow your range of vision

Cognitive distractions such as talking on a cellphone can withdraw our visual attentiveness because it overloads the brain’s attention capacity. Studies show that cell phone use causes “inattention blindness,” meaning people distracted by phone conversations are unable to see and process the same number of visual cues they could without the distraction.

In fact, your complete range of vision may narrow while on the phone. The landscape you’re able to see under normal circumstances shrinks to a small window of what’s directly in front of you when you’re talking on a phone. When you fail to see important details and are unable to process what’s happening across the entire road environment, you’re unable to respond quickly to a potentially dangerous situations.