Distracting car passengers

How distracting are you as a car passenger? The answer could lie in your own driving skills....
20 January 2019

Interview with 

Duncan Astle, Cambridge University; Helen Keyes, Anglia Ruskin University




Joining Katie Haylor to cast their eyes over the latest neuroscience papers were cognitive neuroscientist Duncan Astle from Cambridge University and perceptual psychologist Helen Keyes from Anglia Ruskin University. First up, Helen came across news of research that could put a few passengers in a spin!

Helen - They wanted to address the idea that we know that in-car conversations are less distracting than conversations that happened, for example, on the phone for drivers, probably because passengers tend to modulate their conversation. So if a risky driving scenario arises a passenger will generally be quiet and stop the conversation, so they wanted to address this: would experienced passengers modulate their conversation more than a novice passenger? So a novice passenger might be aware of the driving danger that's happening.

Katie - So is this along the lines of if you are an experienced driver you can appreciate that roundabouts take, for example, quite a lot of concentration, so I'm going to hush up, be quiet and let them get on with it?

Helen -  Absolutely, we call it situational awareness and we're wondering whether the passenger situational awareness would help the driver to also increase their situational awareness and not get distracted.

Katie - OK, so how did they study this then?

Helen - So they had forty, two person driving teams in a lab on a driving simulator and the teams would be watching driving scenarios that would include some hazards, and they were chatting. What was really happening was that they were having a word association task game, where the passenger would say a word such as yellow and the driver would say an associated word such as lemon, and then they would measure two things. They'd measure conversational modulation, in other words the length of time between the words. A bigger gap would mean you're taking into account the driving scene, and they also measured your situational awareness following each clip. So you'd be asked questions such as what color was the car behind you? Did you notice any traffic signals? Things like that to see what the drivers awareness was of the situation.

Katie - So, what did they find out?

Helen - They found that having a novice passenger led to less conversation modulation. In other words, novice passengers didn't stop talking when a dangerous situation arose, and interestingly having a novice passenger significantly reduced the drivers situational awareness. There wasn't any conversational modulation, therefore novice passengers are very distracting and therefore the driver situational awareness was worse.

Katie - This sounds quite significant, certainly not something that I had really appreciated before. How common is this knowledge?

Helen - We know that for example, when you're a learner driver you're only allowed to have somebody in the car with you that is an experienced driver with more than three years. So there is some awareness of this, and we are thinking about bringing in graduated drivers licenses. In fact, they are almost certainly going to come into the UK and they're already in existence in other countries and a graduated driver's license you would have for maybe two years after you pass your test. It might do things like limit the number of passengers in your car, restrict the hours that you are allowed to travel at, and the speeds you are allowed to go at. But studies like this are kind of showing that maybe we should have more of a focus on passenger experience, not just number of passengers.

Katie - And what about age? What about kids, for instance, screaming in the back of the car. Surely that's distracting for drivers?

Helen - Yes it's a big frustration. A kid screaming in the background is one of the most distracting effects you can have, particularly if they are your own children. So in this study when we're talking about novice or young people being quite distracting, we tend to be talking about young adults. But there's a whole separate category for children that's definitely distracting influence, which is going to be quite tricky to make laws about how distracting your own children are.

Katie - Okay. So bottom line, what should someone take away from this study?

Helen -  If I were a novice driver and I'd just learned to drive, just passed my driving test, I think I would have a stern word with anybody I was going to be sharing a driving situation with as a passenger to either not speak with me, which is a good idea, or else I'd be aware myself not to have some novice passengers in the car with me.

Katie - Wow, so I can legitimately tell my friends to shut-up because I just passed my driving test?

Helen - You have my blessing, yes.

Katie - Duncan, do you have any thoughts or comments you'd like to add?

Duncan - It’s very interesting because it implies that even when we're not driving but we're just in the car, on some kind of almost subconscious or implicit level, we're appraising the situation and moderating our conversation, our behaviour accordingly. And that to me is very interesting, because as someone who drives a lot but also as a passenger quite a lot in the car, I'm totally unaware. But, on some level I must be doing it, right? If I'm an expert driver and I'm moderating my conversation.

Helen - I love that you describe yourself as an expert driver! Congratulations, but secondly yes, expert driver, I'm sure you are modulating your conversation. Absolutely, and the fact that you're not aware of it means you probably are an expert driver, but you're just doing it subconsciously.

Next up, Duncan Astle took Katie Haylor through a paper that's rather close to home!

Duncan - So this is slightly self-indulgent as this is one of our own papers. How do we study the human brain? And one of the main ways is we take a cognitive skill or behavior that we're interested in and we group everybody together that has that cognitive skill or cognitive impairment or behavior, and then we compare them to a control group and we put both groups in the brain scanner and whatever difference we find is the neural correlate or the brain correlate at that particular aspect of behavior, and almost everything we know about brain behavior relationships in human beings is derived using that kind of logic.

But there's a really important problem with it. Even though we've grouped people according to our behavior or cognitive skills, it doesn't mean that has arisen for the same reason in every individual in that group. There might be multiple different pathways that lead toward that particular behavior and by putting them all together in one big group, we're actually really muddying the waters and maybe not really getting to the underlying root cause of why that behavior might occur in the first place and so that's the problem that we were trying to address.

Katie - So you’ve turned brain science on its head then?

Duncan - In a way. Yes we use three large samples of individuals, one from New York, two from here in Cambridge, and rather than trying to group them using cognition or behavior we put the brain data itself into a machine learning algorithm. So, just like the country's road network is organized around some really big motorways, there are some really big pathways in the brain. They're made of white matter and they are really designed for the smooth, efficient transfer of information over really quite large distances within the brain and so we extracted information about the quality of those pathways in all of our subjects and we submitted those to a machine learning algorithm. What it was trying to do was to see whether it could group individuals because they have very similar brains to one another, those tracks or those motorways, and that they're different from people in another group rather than grouping according to cognition or behavior.

Katie - OK, so how successful was it? What did you find?

Duncan - And so we found that we could group them. One of the interesting things we found was that there was one particular set of pathways called the cingulum, right at the front of the brain, part of the brain called the cingulate cortex, all the way to the back and then around and underneath, and these tracts seem to be really important for determining which group subjects went into. We then had some functional brain imaging data looking at brain metabolism and we found that actually the areas that this tract connects were also different across the groups, and then we looked at the cognitive skills and we found that they were also really very very different. So grouping on the basis of subject’s brains unlocked a way of looking at behavior that we otherwise wouldn't have learnt about.

Katie - Is this study one that's more for the scientists?

Duncan - Well I think it's for anyone who's interested in the brain and how the brain, our brains, might relate to our behaviour. So the way that we traditionally think about it is that we, let's say, we group everyone that has long term memory problems and then we think - “what's the brain cause of that”? But actually, maybe there are multiple different brain causes that can give rise to a problem with long term memory. it's very hard for us to know that unless we start to group people by the underlying brain physiology, and this paper is important I think because it's the first demonstration that that can be done.


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