See bike say bike

Have you ever had a SMIDSY? Looking at a common type of road accident...
01 October 2019

Interview with 

Peter Chapman, University of Nottingham


Motorbike in traffic


Have you ever had a SMIDSY, or even a near-SMIDSY? To explain, Chris Smith spoke to Peter Chapman, from the University of Nottingham, who has been looking at the cause of one of the commonest types of road accident...

Peter - One of the nastiest types of crash on the road, is when you're driving up to a junction in a car, you look right, look left, look ahead, pull out, and then smack, you're hit by a vehicle from the side that you hadn't seen. Typically it's a motorbike that hits you. And they were just driving along minding their own business and you'd pulled out in front of them. This happens so often that motorcyclists have a special name for them. SMIDSY crashes; “Sorry mate I didn't see you.” Which is what the driver says iIf they've got someone to talk to, very often the motorcyclist doesn't survive that kind of crash. About 90 motorcyclists in the UK die in that kind of crash every year. But it's also a real psychological mystery what's gone on here.

Chris - Indeed, why has the driver, despite looking right and left, by and large missed them? How did you try and get underneath why this is happening?

Peter - Well we started using a high resolution driving simulator, where we could really put people in just the right sort of situation, and we recorded their eye movements, so we could see exactly where they were looking around as they came up to junctions, and we got people driving through hundreds of junctions, looking around, making decisions as when it's safe to go. And then every now and again, we just stopped the simulator, just as they pulled out and we asked them, “what's around you, describe the vehicles.” But a weird thing that happened is quite often, there'd be two vehicles coming, one from the left, one from the right, and the person would say, “I remember a car on the left it was a blue car it was about there.” Then we’d say, “anything else.” No, they'd say. That was weird because we used the eye tracker. We could see them, just four or five seconds earlier looking straight at a motorbike coming from the other direction but they'd forgotten it.

Chris - Now we know there is this phenomenon of inattentional blindness. People do various demonstrations of this, where they ask you to count someone bouncing a ball and in the background there's a gorilla skipping through the picture, and they don't even notice it. Is it just a manifestation of that that's going on? The motorbike is quite small, there's lots of other distractions, so they just ignore it?

Peter - We're very used to that kind of explanation, that you haven't taken in the motorbike. But the surprise for us is, when we looked at what predicts whether you do remember the motorbike, it's not whether you looked at it, or how long you looked at it for, it's what you do afterwards. So the more things you look at after the motorbike, the more likely you are to forget it. Now that looks like forgetting, not a failure to attend to it in the first place.

Chris - Does this mean then, that when people say there's too much roadside furniture, too many distractions, too many things to look at, actually they've got a point? We are potentially making the roads more dangerous by cautioning people about everything.

Peter - Well the issue there is how selective the driver is. If the driver looks at the right things, and attends to the right things, then there isn't a problem. If however, you make the junction so complex that they need to look at lots and lots of different things, that is going to be more than they can remember.

Chris - Does the research highlight any interventions that we could meaningfully make though? Because when you're with your driving instructor, they dutifully say to you, “mirror, signal, manoeuvre.” Should that be, “mirror, signal, motorbike, manoeuvre”, or something like that? Is there any kind of thing we can drill into people that would reduce the likelihood of this sort of accident happening?

Peter - Well I do have one suggestion. So it looks as though this error is a limitation in short term memory. Now what we do know about short term memory, and we've known since the 1960s, is that you've got two types of short term memory that are essentially independent systems. You've got visuospatial working memory, for the things you look at and you've got phonological short term memory. That's a verbal form of store for things you say. The two are separate. So I've suggested that if you're at a junction and you see a motorbike or a pedal cycle coming, you just say aloud or under your breath, “bike”, that will automatically encode it in phonological working memory. That gives you extra capacity, essentially doubling the amount of stuff you can remember. See bike, say bike could be a simple intervention that might make a big difference.

Chris - So the bottom line then would be; motorcyclists should do their best to be as obvious and eye catching as possible, which most of them do, don't they? Drivers should be drilled to not just say, “I'm approaching a junction”, but to call out, “I've seen a bike”, and remind themselves they've seen a bike, and perhaps also not just look right and look left, but do it again.

Peter - The key thing I think drivers have to realise, is that their short term memory isn't as good as they think. We all have the idea that we can remember everything around us, but you only have to trust your memory for something you're not looking directly at to realise that you don't actually have that memory. And that's what's going on at junctions. People assume that they would have remembered something if it were there. So they pull out. I think drivers need to realise that actually, it's harder than that. If you want to remember something you've got to work at it, and saying bike is a good way of working at it, that guarantees you will remember it.


Add a comment