What listening to someone speak does to your brain while you?re driving


In my lab?s studies of multitasking at Carnegie Mellon, we found that the brain activity associated with driving (using a simulator) decreased by 39% when the driver was also listening to someone speak. (Our participants steer a car along a winding road in a simulator inside an MRI brain scanner). Of course, the driving performance deteriorated (poorer lane maintenance, hitting the berm) when listening to someone speak, as David Strayer?s studies and others? have shown. So even though we might feel that talking on a cell phone is okay because ?we?re not doing anything anyway? while driving, the fact is that normal driving performance requires a certain amount of brain work, and listening to someone speak very substantially decreases the amount of brain resources available for driving.

This study was done with participants in their early 20?s. This effect of distraction is very likely larger for older people.

It is interesting that you can?t will yourself not to process what someone is saying to you. When we asked our participants to ignore what was being said to them, the outcome was that they were completely incapable of ?blocking out? spoken language. Understanding spoken language (in a language in which one is fluent) is so automatic that it is literally unstoppable. We can see the brain activity that the spoken language generates in the brains of people who are trying to block it out. So if you are on cell phone and your conversation partner keeps talking as you enter a demanding driving situation (an intersection, a school zone, a jaywalker, sudden braking by the car in front), you are out of luck.

Other research has clearly established that using a cell phone while driving significantly increases the risk of an accident. Our contribution is to show that the constraint comes from the limitations of the human brain, limitations that apply to all of us.

Here is the link to our published article: http://www…ations.htm

Just, M. A., Keller, T. A., & Cynkar, J. A. (2008). A decrease in brain activation associated with driving when listening to someone speak. Brain Research, 1205, 70-80.

Here is a picture of the brain activity, averaged over our participants:


Once you’re married for a few years, blocking out another’s conversation is easy. At least that’s what the missus tells me.

Ed B.


Let Me See If I’ve Got This Right. Using MRI And Simulators In A Study, It Was Determined That Distractions In One’s Vehicle While Driving Are Distracting To The Driver ?

Who’d have thought that distractions in a vehicle would negatively impact a driver’s concentration and ability to operate a motor vehicle ? That sounds dangerous. Thanks for the enlightenment.



Throw a stick of gum in the mix and you probably will not even get the permit to continue with the testing.What is your personal experience with driving and talking at the same time, not really an issue is it?


Just to play devil’s advocate, studies have shown that the brain isn’t fully mature until the person is well into his 20’s. Extrapolating that “This effect of distraction is very likely larger for older (than early 20’s) people” seems to be a supposition without fact. I’d be interested to see you test this hypothesis.

Now here’s where I think you went wrong in your procedure and your conclusion:

You presented the test subjects with a “Driving” simulation which consisted of steering a car at a constant and non-controllable speed (43mph) along a road with no obstacles, and only the occasional splash of scenery (hills and water). All they could do was steer, and they didn’t even have a steering wheel to do it with - instead they used mice and trackballs which require minimal movement and are, especially to people in their 20’s who grew up on first-person-shooter video games, second nature to use.

To an experienced driver, giving them a curving road with no cars or other hazards, and not even making them handle all the controls they would need to handle in a real car, this simulation could be done with one lobe tied behind their back.

Then you told them not to think about the conversation, which as I’m sure you know from reading Schneider and Wegner’s 2003 “White Bear” paper, virtually guaranteed that they focused on the conversation.

In short, you bored them to death, and then acted surprised when they focused on actual stimuli after having been psychologically set up to focus on that very stimuli.

I’d be more interested if you did a study in which you simulated driving in traffic, with subject-controlled steering, acceleration, and braking, and while presenting them with typical driving hazards (being cut off, tailgating, confusing exit signs), and you avoided stacking the deck by refraining from telling them what not to think about while driving. I’d wager that at least some of your subjects would lose focus on the conversation when things requiring more attention occur in the simulation.


[~ This post was not in the least flaggable ! ~ But I took out the stuff that probably made some twit flag it - even though none of it was actually flaggable. (Oh but I guess I said that already).]

Sorry but you guys give serious research a bad name.

First, what the heck does this have to do - specifically - with cell phones? Answer - obviously not a thing. Would everyone please get over it. People have been talking in cars since there have been cars. It sounds like you have a piece of research that you want to use to say how bad cell phones in cars are. All it says is that any sound equipment and other passengers in cars are bad.

Second, anyone who would say that it is impossible for a human to block out & not process spoken language is someone who is too impressed by their overly expensive laboratory equipment.

So all you do with this drivel is indicate that many people who do research in laboratories know how to operate lab equipment and process statistical models, but still can’t think their way out of a paper bag. It gives serious research a bad name.

Edit from the original flagged post: my post could be read as “even if your results are any good…” shadowfax gives good reason to think that you guys aren’t even that good in a laboratory.


I was a government employee with a hand held or a car 2-way radio, and U just learn to ‘filter’. I don’t believe the average person is motivated to do this.
Even listening to “tunes”, I can snap out of it and react, because I just don’t let the radio rule me too much. Eyes can be sentinels, we are not merely spectators in our cars.

What gets me is people who have to turn their head towards their passenger in order to talk…Dumb.


I personally don’t doubt the OP’s postulates. I find it difficult to really concentrate, as in when I’m trying to navigate my way through Boston traffic, and conduct a conversation with a passenger. And I find it easier to concentrate on the traffic when there’s no passenger at all.

In most driving circumstances, and with 40+ years of daily practice, it relaly isn;t a problem, but under high traffic urban conditions it is.


Aside from the poor methodology of the OP’s experiment, my objection is the implied “and therefore even hands-free cell phones should be outlawed” statement.

I’m certain that you do not instruct your passengers to sit quietly and not say anything outside of an emergency until you reach your destination. I’m equally certain that you are capable of focusing less attention on the conversation when circumstances dictate. So am I. I can easily talk to someone while driving down a lightly-trafficked road, but when things start to require more concentration, the conversation takes a back seat.

The problem with cell phones is not that cell phones have some magical property that makes it impossible for us to focus on driving. It is that some drivers make the choice to prioritize cell phones above driving in their attention hierarchy.

If we are to make the argument that cell phones should be banned because some drivers use them inappropriately, then we must by extension make that choice with all other distractions, including the radio.

Oh, and some drivers don’t turn on their lights at night, and so we should ban night driving as well.

Point being, penalize those who use them improperly rather than lumping all of us in the same category as the morons. I’d fully support extra charges against someone if it can be shown that they caused a wreck that should have been avoidable and that they were on the phone when they caused it. I’d also support extending DUI laws to cell phone users if they are caught driving erratically while dialing or texting. Such laws would target the actual problem element rather than mindlessly blanketing all of us with restrictions that we don’t need.


I won?t comment on the methodology used in the experiment, but based on personal experience I agree with the conclusion. The study doesn?t differentiate between the types and degree of distraction and its impact on driving safely. This I think is the source of most of the negative comments.

In roughly increasing order of distraction I offer the following observations.
Listening to the radio, especially talk radio, even if you are inclined to talk back to the radio isn?t that distracting. It is essentially a one way ?conversation?. No response is needed or required. The driver has almost complete freedom to focus on driving. This might also be said of future ex-wives and mothers- in law. But, did you ever miss the punch line to a good joke because some moron on a cell phone wandered into your lane?

Two way radio
Conversations over two way radios are essentially single duplex. Both parties are aware the conversation is constrained to one talking and one listening. Both have control over when they talk and when they listen. Unusual pauses and ?say again? are common. This is a little but not much more distracting than listening to the radio.

Passengers and drivers share the same environment. There are visual and physical queues to direct the conversation. The conversation tends to ebb and flow based on what is happening in front of the car. Smooth empty highway, no problem. Wheeling through NYC traffic passengers are usually too afraid to talk. But, when my passenger starts hitting the passenger brake pedal or grabbing for the door I know it?s time to switch attention back to driving. I find conversations with passengers in the back to be more distracting, particularly when then yell out OMG look at that. They don?t share my environment. They are looking out a side window watching some house burn down a quarter of a mile away.

Auto cell phone users
Cell phone calls demand to be answered regardless of the driving conditions. After all, if you are going to let it roll to voice mail why have it on in the first place. The caller doesn?t know and usually doesn?t care if you are driving at high speeds in bumper to bumper traffic. The conversation is fully two way and if your boss, significant other, or important account is on the line won?t be ignored. The caller requires your immediate attention. When I see a car changing speeds, wandering across the lanes, stopped at green lights, rolling through red lights or incapable of negotiating a turn I used to know the driver was drunk. Now, if it is during the day, I know they are on talking on a cell phone. Sometimes I?m wrong. Just the other day a car exhibited all of the signs of a cell phone distracted driver. It turned out a father was teaching his teenage daughter to drive. The BMW 335 fooled me.

The problem with drivers impaired by alcohol or cell phones is that only think they are driving OK.


I’ll comment on yours: Using limited personal observations to make generalizations about the entire population is poor science, and therefore the conclusions must be dismissed.

I agree that drivers on cell phones often drive like idiots. I won’t agree that it’s a given that they will. If drivers prioritize driving above everything else, they’ll do fine. The trouble is that many drivers don’t. They eat. They read. They watch TV. They text. They have sex (I’ve actually seen this). And yes, they talk on the phone. And even drivers who apparently have no distraction can often be observed driving like morons.

The trouble isn’t cell phones, and banning cell phones while driving won’t solve anything. The trouble is that we have a whole nation full of crappy drivers who don’t care about learning to drive properly, don’t care about learning how the car will behave in various situations, don’t care about safety, and many of whom also think the interstate is actually a race track. You can ban anything you want but until you start insisting on higher-level driver training and tougher penalties for stupid driving, the problem won’t go away.

But cell phones sure are a convenient scapegoat.


The conclusion of the study supported my personal observations. It wasn?t science. It was an opinion.

Distracted behavior on our highways for many reasons is deplorable. Cell phone use while driving as scapegoat for all distracted driving? Hardly. In my State drivers using cell phones became enough of a problem to provoke a public debate and resulted in a ban on the hand held use of cell phones. An individual?s ability, or lack of, is irrelevant. It was the irresponsible behavior of many than led to the ban. It is the same reason we have DUI laws, speed limits, vehicle inspections, building codes and FAA inspection of homebuilt aircraft.

I would like to see better driving training and tougher penalties for stupid driving, but defining stupid is a legal impossibility.
Don?t shoot the messenger.


My wife tells me the same thing, several times a day. I generally answer with a yes dear at several minuets intervals.