Hot off the press
Cognitive neuroscientist Duncan Astle from Cambridge University and perceptual psychologist Helen Keyes from Anglia Ruskin University told Katie Haylor about the neuroscience papers that caught thier eyes this month. But first, Katie asked Helen what being a psychologist is all about...
Helen - Well for me I’m a perceptual psychologist so I look at the way the brain perceives and interprets visual and auditory information. So for me it involves a lot of experiments, a lot of computer experiments and driving simulators and things like that.
Katie - Now as a humble radio producer who is going to take her third driving test in a couple of weeks. Do you have any advice to help me actually pass?
Helen - Well very embarrassingly I only passed my driving test last year with professional driving researcher. So I think I almost failed the driving test but I was telling my driving person that I was a driving researcher and he was so impressed that he was like “well she must know what she’s doing!”. So I have no advice but you could lie and say that you're a driving researcher.
Katie - Okay thanks very much! Now in a moment you're going to tell us about what's caught your eye neuroscience wise this month. What are you going to talk about?
Helen - How cognitive distraction can affect your movements and driving behavior.
Katie - Very relevant to everyone, including me! We’ll come back to that. Duncan Astle is a cognitive neuroscientist from Cambridge University. What do cognitive neuroscientists get up to?
Duncan - Well all sorts of things. In my case we study cognitive processes like attention and memory. We study them in children in our lab, we study why they vary so markedly across different kids and the underlying brain hazards and brain physiology that gives rise to those differences.
Katie - And what paper are you going to be talking about? Is it learning related?
Duncan - It is a little bit true to form. I've chosen a paper that's looking at the development of the hippocampus in childhood and what might influence it.
Katie - The hippocampus being a part of the brain?
Duncan - Yes.
Katie - Okay. So let's start off back at Helen. Helen, can you give us a brief rundown of your paper, what the team was setting out to do, what they did, what they found and why it's important?
Helen - It's all about when you see a visual sign, for example of visual roadsign, you actually say the words, so if you see a picture of a person with a shovel you say “roadworks” you say it internally you articulate it and that articulatory rehearsal is quite important for remembering and storing that information temporarily. So you see a visual sign, you need to rehearse it using an articulatory mechanism in order to keep processing it.
So this paper is looking at people driving on a track and whether if they interfered, if they suppressed, your ability to rehearse something - your articulatory rehearsal mechanism - if they suppress that by getting you to count from one to 30 or even more complexly to count down from 50 down to one. If they suppressed your ability to see a road sign and kind of rehearse it, would it affect your driving behaviour and would it affect your gaze? So that they were tracking the participants while they're driving.
Katie - Okay. And did it?
Helen - It did. I'm not sure if the paper was quite successful. So the paper found that if you had a complex articulatory suppression so if you had to count downwards, backwards from 50 when you're looking at a road sign you had fewer gazes at the relevant visual information, you dwelled on things for less time, which says you were paying it less visual attention and also you made more driver errors.
So that's quite interesting but it only happened for that complex suppression so counting for 50 down to one. It didn't happen for simple suppression counting one up to 30 which suggests to me that it's more of an attentional effect than just suppressing your articulatory rehearsal because when you’re counting 1 to 30 you're suppressing your ability to articulatory rehearse something. So it should really have a similar effect if that was really what was driving this. But it looks like it's just a straightforward effect of if you're doing a complex cognitive task while driving, you’re gazing at things in a less relevant way and your driver behaviour suffers.
Katie - So I'm guessing we knew this sort of thing before right, similar to not being in a mobile phone because that's cognitively distracting, maybe even talking to other people or shouting to your kids in the back of a car, that sort of thing?
Helen - Absolutely and we know a few things about distraction. So we know usually that visual things distract you more on a visual task like driving. So the worst type of radio you could listen to would be listening to a football match being played when you're using your visual imagination. It really takes your visual attention away from the road but this is kind of suggesting that, yes, when you're distracted by hearing things it's also going to affect your driving performance. We know that when you're talking on the phone what's really distracting is the attentional capacity that’s used so if you’re addressing a question or if you're really engaged rather than sitting beside a passenger and talking at a more relaxed rate, that's not such a big issue. So mobile phone use is a problem.
So it's not adding a massive amount of new things but it is quite interesting just showing us directly that if you have an auditory cognitive task when you're articulating something in your head, even just thinking, that it's going to take from your visual attention so thinking of cognitive tasks when driving, complex cognitive tasks, is going to have a pretty big effect on your driving.
So don’t try to do complicated maths problems whilst you’re trying to drive up a motorway?
Helen - How else would you get your kicks out of life?
Katie - Any questions? Duncan -
Duncan - So if people’s sub-vocal rehearsal mechanisms are important for how they process and maintain street sign information, we know there’s a large degree of variability in how good people are at that. Does that mean that there’s lots of variability in how good people are taking on board and remembering road signs?
Helen - I'm really glad you asked that because there is some really neat studies showing that a person's working memory capacity is directly related to the amount of driving errors they make. So that's exactly right. It just seems like your working memory capacity if it's quite small it's going to get used up quite quickly and you're not going to be able to process those signs or respond appropriately to your road environment.
Katie - So Duncan we're learning and memory now, so can you just remind us what your paper is about?
Duncan - So my paper is about the development of a particular brain structure called the hippocampus in children aged four to seven. So we've known for some time that a child's early environment can shape all sorts of aspects of their development and can lay the foundations for lots of really important things. For instance long term mental health those kinds of things. So people have been really interested in what the mechanisms might be, but it's really hard to study it because of course it takes a long time for people to develop. And so as a scientist it's really hard to study because you have to wait an awful long time to get your data. So one thing people have done is use different kinds of models like they study them in mice and rats and that kind of thing, who grow up a lot more quickly. So we know something about the mechanisms that might be important for how an early environment can shape things like memory over time.
But what this group did which was really really nice is that they collected fMRI data and structural MRI data of the brain when children were four years old. They also collected lots of other things, questionnaires about home life and about their parents and their parenting style. They then saw everybody again three years later and one additional test that they did was a stress reactivity test. So they gave the children these very demanding tasks and they actually adjusted the amount of time the kids had to perform them to the point that it became impossible. That becomes quite stressful and there's a hormone produced that you can measure in saliva called cortisol which gives you a measure of how responsive people are to stress.
So they have this really nice data set where over time they can explore how things like parenting change, how things like the hippocampal change which we know is really important and memory and how things like stress reactivity change and what they demonstrated really nicely was that early environmental influences in particular early parental behaviours had a really strong impact on the growth of the hippocampus and that it's much more reduced if parents have a very negative parenting style and that the children are much more reactive to stress and stressful situations, who have grown up in those environments. And that's a really hard study to run and a really valuable dataset collect and it's really nice because it actually ties back to lots of other biological work that was done in things like rats and mice. But it's one of the very first neat demonstrations of it in human children.
Katie - Okay so what can parents take away from this study?
Duncan - So what are known as harsh parenting styles, so a particular approach to discipline for example and rules, if it's extremely harsh then that can actually have a negative impact on child development.
Katie - How harsh are we talking about? Telling people off, or are we talking about being aggressive?
Duncan - Usually aggressive. So by and large boundaries and so on have been shown to be a very good parenting strategy in combination with a kind of warm and loving approach. But if parents show signs of aggression and aren’t able to control their own tempers then that can be seen as a harsh parenting style and that can be shown to have a negative impact on kind of long term healthy development.
Katie - Okay. Questions or comments?
Helen - How can we tell the direction of the effect? So if you have a child of difficult behaviour may be due to a small hippocampus, perhaps they you know induce more aggressive behaviours in their parents?
Duncan - Absolutely right. So it's very hard to disentangle these things. You can have a go at seeing what came first. In their data the sample size isn't massive, but it suggested it's the parenting styles that come first. But your question leads to a wider debate about kind of chicken and egg and these are kind of dynamic situations and it's very hard to disentangle them. So even though in their data it looks cleaner, I suspect in a larger sample you would see that there are much more subtle interactions between different factors.