Crowd Control, Football Hooligans and Singing Mosquitoes

30 July 2006
Presented by Chris Smith, Kat Arney


I predict a riot... or not. This week we're joined by crowd control experts Dr Clifford Stott, from Liverpool University, and Dr John Drury, from Sussex University, who'll be discussing why violence kicks off at football matches, how to spot a spat and the science of mass evacuation. Taking us on a flight of fancy, Dr Gay Gibson, from the University of Greenwich, who describes her research into the harmonious music of mosquitoes, and in Kitchen Science, Derek Thorne bangs out a tune from an oven shelf...

In this episode

See the Attachment... Ooops I Forgot.

How many times have you done that - sent an email and forgotten to add the attachment? Well now help is at hand in the form of  a system being developed by Fernando Pereira and colleagues at the University of Pennsylvania. An article in this week's New  Scientist describes how the team are developing software that can scan an email for clues hinting at a missing attachment, and  then pop up a reminder before you hit send. To develop the new tool the researchers used 8000 publicly-available emails from a  US company and taught the software to pick up the patterns of words and phrases associated with the presence of attachments.  Then, to test it, they ran it through a batch of fresh emails from which it correctly predicted, in 85% of cases, those that contained an attachment.

Operation Concealed Swab

Doctors now have a clever way to make sure that patients aren't stitched up by shoddy surgeons leaving pieces of operating equipment inside their bodies. Writing in the journal Archives of Surgery, anaesthetist Alex Macario, from Stanford University  in California, has come up with the idea of using the same RF-tags that help to deter shoplifters to label operative equipment. This way a wave of a detector wand over a wound before it is closed can be used to confirm that no stowaway scissors, scalpels or swabs are left behind inside the patient. In an initial trial, tagged items were concealed inside wounds before closure and a surgeon, who id not know where or how many items were left, was asked to locate and remove them, which took an average of 3 seconds and there were no false positives. US company ClearCount Medical is now working on ways to miniaturise the tags, which are about the size of a small coin. As this is larger than some operative equipment, there's some way to go. Also, although incidences of items being left behind inside patients are rare at 1 case in 10,000, the consequences for an individual patient can be devastating which is why such a simple and low cost approach like this could make a huge difference.

Using Bacteria to Mine for Precious Metals
with Dr Anna-Louise Reysenbach, Portland State University

Chris - Here's a discovery that could quite literally be worth its weight in gold. A US researcher called Anna-Louise Reysenbach from Portland State University has found a class of extreme bacteria that can thrive in acid and near-boiling water. These are so-called thermoacidophiles and they've been found in hydrothermal vents on the ocean floor and they might be able to help above ground. This is because they could help in the extraction of precious metals from the debris that's left over in mines.

Anna - Louise: At deep sea hydrothermal vents where the hydrothermal fluid, that very high temperature hot fluid that comes from deep within the Earth's crust, that fluid which has pH of about 3.5, when it mixes with the cold seawater it makes these beautiful chimneys, these chimney structures, these porous rocks, and it's been predicted that in those chimneys there are areas where there's low pH, and so you'd expect that there would be microbes that would live at these low pH environments, and yet nobody has every discovered a thermoacidophile, which is an organism that grows at low pH and at high temperature from deep sea vents.

Chris - Well, you've obviously succeeded, so how did you manage to recover these particular organisms and then culture them?

Anna - Louise: First of all the one thing I knew based on some molecular signal that a relative of one of these thermoacidophiles actually lived at these deep sea vents, and because of some geochemical modelling predicting that there were areas in these hydrothermal chimneys where there was low pH I decided that we should really try and look for microbes that can actually grow at these low pH's, and so we just tried to grow them under those conditions and voila, we got them.

Chris - How did you actually recover these ones?

Anna - Louise: Basically we used remotely operated vehicle called Jason II which is a little vehicle that's tethered to a ship and we can send it down, we have pilots that manipulate these hydraulic arms that then take samples for us at the bottom of the ocean, and then once in the lab, we just ground up the rocks, kept the rocks anaerobic, because this organism because this organism's anaerobic, it doesn't like oxygen, and we then inoculated bits of that rock into our acid media and then managed to get this little bug to grow.

Chris - What do you think the applications of them might be, because the mind boggles, you've got something which grows under extremely severe conditions?

Anna - Louise: One of the applications would be in bio-mining, where the mine tailings are often very acidic and there are organisms, thermoacidophiles actually from terrestrial hot springs that are used to remove some of the last bits of the precious metals, so this organism could potentially also be used for such an application.

Chris - And what are you going to do next? Will you be sending Jason back for some more samples or will you be focussing your attention on the one bug you have got so far?

Anna - Louise: I think we're going to focus, for the moment, on looking at the distribution of this organism at other deep sea vents, so we have some samples from many different deep sea vent environments and so we've been trying to isolate it from some of the other places around the world, for example the Indian Ocean, the Pacific Ocean, the East Pacific Ocean, this one came from the South West Pacific, so we're trying to look at the distribution and see if its relatives are similar, if they share the same characteristics of being acid loving, heat loving deep sea vent microbes.

Chris - Anna-Louise Reysenbach from Portland State University who's managed to recover the world's first example of a thermoacidophile from a deep-sea vent.

- Crowd Control at Football Matches

Clifford Scott is researching hooliganism, and how to deal with them

Crowd Control at Football Matches
with Dr Clifford Stott, University of Liverpool

Chris - Could you just give us a gentle introduction to your work?

Clifford - A gentle introduction; I'm not sure if that's easy. I suppose in a sense what I've been working on with John as well is basically a theoretical model of what makes collective behaviour in crowd events possible from a psychological point of view. So it's the psychology of crowd behaviour. From that theoretical model we've been able to start asking important, difficult but practically important questions about how we manage crowds in society; particularly at the critical times of violence at political demonstrations and in football crowds and at various other events like that.

Chris - You went out to join the World Cup but not to watch the game but to watch the people.

Clifford - Yes, it's one of the difficulties I have. I'm always working and I can't switch off. If I go to a football match I spend most of my time looking at the crowd and not the game but I'm starting to come to terms with that. I go along and take a group of researchers with me and we spend lots of time in crowd events just making systematic observations and looking at events. In particular we focus on interactions. The particularly important interactions we look at are between the police and football fans. What we've found is that those interactions are critically important in determining how people behave in a crowd event, particularly as this relates to the emergence of widespread rioting.

Chris - So what do you do? Do you look for hot spots in the crowd where you think trouble is about to break out and then watch that dynamic going on or do you just chance it and hope that some trouble will break out near you, in which case I don't want to come to a football match with you?!

Clifford - We're pretty good at our jobs so we do end up quite often being in the right place at the right time. But it is particularly opportunistic and in part that's why we study football crowds. We always know where football crowds are going to be, we know that it's highly likely that there will be problems around a football match, and we know that the police are almost invariably going to be there. So it makes that opportunistic kind of approach to studying crowds a lot more fruitful because we tend to see a lot more going on in crowd events at the football. From that we can learn so much more about how crowds work.

Chris - So what's the recipe that turns a crowd of people that's just there to support something they view as fun into something in which they become quite aggressive and sometimes murderous?

Clifford - I think there's quite a lot of misunderstanding about how crowds work. One of the things we've begun to understand is that crowd behaviour is the result of particular forms of interaction. The way groups interact during a crowd event, and you must remember that the police are a group during a crowd event, have a fantastic impact on how crowds behave and on their psychology. In particular, it affects people's sense of what's right and proper behaviour and also what it's possible for people to do collectively. That dynamic of what we call legitimacy and power really functions to make particular forms of group behaviour possible. What we find id that where to police act against the crowd in ways that the crowd see as wrong, and when the police are particularly indiscriminate in the way that they treat crowd members, those are the kinds of situations in which riots tend to develop.

Kat - So if they see the police beating up a woman or picking on someone when they shouldn't be?

Clifford - Yes, that kind of sense of the police doing something wrong. We must remember here that what we're talking about is a psychological dynamic. It doesn't really matter if the police are doing that or not. What matters is that there's this emergent perception in the crowd, and it's really that objectivity which drives collective action. If they feel that the police are doing something wrong, then they feel that by acting against the police that they're doing something right.

Kat - So it has a sense of group injustice about it.

Clifford - Exactly.

Kat - What causes a football riot to kick off or any sort of big event like this? What nucleates it?

Clifford - Well it's very very complex. If we had an answer to that question right now I don't think I'd have a job. What we're looking at is to try and change people's views about why crowd violence happens in the context of football. Overwhelmingly people have an opinion about this and people think generally that it's caused by football hooligans. But what we're beginning to find is that that's not a very good way of looking scientifically at the problem. Science is all about bringing to bear scientific knowledge and data about a particular issue and what we find is that this whole idea about hooliganism is completely useless when it comes to understanding these riots.

Chris - Are police anywhere else in the world doing it any better than we are here?

Clifford - There's good practice and there's bad practice all over the world. What we do is to look at the dynamic as a social conflict. I think that the kinds of dynamics that we expose in our study of football violence have a great deal of applicability and I think that they can make sense of the escalation of violence, for example, in the Lebanon at the moment. So I think that these are general processes of the psychology and the social dynamics of social conflict and there's a great deal of generality there about how we understand it.

- Don't Panic, the Science of Mass Evacuation

How do people behave in a crisis? John Drury is studying how to evacuate people quickly.

Don't Panic, the Science of Mass Evacuation
with Dr John Drury, University of Sussex

Kat - Anyone who was in London about this time last year was shocked to the core by the London bombings. How do you start evacuating people from a situation like that?

John - I think we want to step back for a moment there and consider the concept of crowd control. There's a kind of hidden assumption there that the crowd is the problem and it's down to the authorities to deal with the problem of the crowd. The problems of the crowd are defined as its reduced intelligence, its irrationality, its over-emotional behaviour, and its inability to control itself. This goes back over 100 years to when crowd science first emerged and you see them in the ideas of the police and also in many procedures for evacuating crowds.

Kat - So how instead should we look at crowds?

John - The first thing to point out is that it's in common sense discourse that when there's an emergency, people will panic. When we say panic, what we mean is that people will over-react, they will become selfish, individualised and ultimately ineffective in their attempts to escape because they keep getting in each other's way.

Kat - And how should we get people out of those situations in the most calm way possible? Is there any way to stop people panicking?

John - Well the point I'm trying to make is that panic is a myth. 50 years of research into disasters and emergencies have shown no evidence at all of panic behaviour. What is more common is people obviously feeling fear but evacuating in a relatively orderly way. Helping is very common and deaths are due not so much to people panicking but people often trying to stay behind to help people to get out. They are often in small groups of people and they're trying to help people less able than themselves.

Kat - So people don't run around like headless chickens like you might imagine.

John - Yes, it's a myth. Everyone commented that after the bombings last year, all the accounts mention how calm everybody was and how much helping there was. It was characterised by something about London, or British identity or London identity. But in fact it's a universal phenomenon. Help and co-ordination and co-operation is a universal phenomenon in emergencies.

Chris - It's interesting John because we've had a call in from John in Colchester who's asked whether pheromones or chemicals be used to control riots and crowds? And I know that in the United States, a lot of research has been sunk into microwave guns that can blast plasma at people and give them a little bit of pain if they step into the beam of it. This is a good way of pushing people into submission. Also, there was a group in Washington who was working on the world's worst smell, so that you would release this smell on people and it reduces them to a quivering heap on the ground as you try and hold down the contents of your stomach because it's so unpleasant.

John - Yes and this goes back to my earlier point: where crowd science arose from was the perception by those in power that the crowd was the problem, and so how do we deal with the crowd. Turn it round, and the crowd is actually the solution. Social change comes about through crowds. Progressive social change comes about through crowds. The most uplifting, most constructive and most empowering events in terms of emergencies are due to processes within the crowd itself. The concept called resilience used by the government and used by sociologists looking at disasters refers to a natural quality of people to respond in a constructive and humane way and to co-ordinate through their own natural resources.

Kat - I was reading the paper this morning and one of the classic problems with large groups of people trying to do stuff is getting on an aeroplane. There are various models people are trying to look at to see which is the best way to get people onto a plane. They were saying that people do tend to get in each other's way in that situation. You should put people into the window seats first. Where you have a lot of people trying to go to the same place at once, is there a best way for doing this?

John - I haven't really got a solution for that question but I have a comparison which sheds some light on the issue. Think of a crowd of commuters on the central line and the way they behave and how they feel. They're packed close together, they're uncomfortable, they don't meet each other's eyes and they find physical proximity unpleasant. They are a physical crowd crowded together where they don't see themselves as a crowd or as part of a whole. Take the same situation, yet this crowd is a crowd of football supporters that's just seen their team have a victory. They are singing together and the physical proximity there is an enjoyable thing. So there's something about being a psychological crowd or seeing yourself as a crowd that makes people put other people first, be self-sacrificial, co-ordinate and communicate. Whereas in a physical crowd, the crowd of individuals or consumers competing for space, have a lack of unity. The lack of unity stems from the lack of shared identity, so those people have no shared interest.

- Mosquito Music

If you are a Mosquito, how do you find a mate? Dr Gibson is looking at the mosquito version of a nightclub

Mosquito Music
with Dr Gay Gibson, University of Greenwich

Chris - Now you work on mosquitoes and you published a paper the other day that everyone was buzzing about, you might say, about how they tell males from females. I'd never really considered before that that might be a problem.

Gay - It's not so far off the topic that the other people have been talking about because when mosquitoes get together, they usually do so in a crowd of males. They all gather in the same place at the same time.

Kat - A bit like a mosquito night club.

Gay - That's right.

Chris - But why do they do that? Why do all the males get together?

Gay - Well the males really have nothing else to do in life except hang about and mate. It's the females that go about biting people and drinking blood but the males really don't have anything much else to do.

Chris - The males just drink sugary solution don't they?

Gay - Yes that's right.

Chris - The reason females drink the blood is because it's rich in protein.

Gay - Yes and they need that protein to help make the next generation.

Chris - So you've got a big flock of males hanging about. How does an interaction between a male and female mosquito happen then?

Gay - Well the first problem is that all these males are swirling around each other and they've got to not waste too much time chasing each other because that would lead to nothing. And that's really where the problem started for me. I wondered about how they save their energy for actually chasing the right female when she comes along. It's taken a long and hard think about things. Mosquitoes have very specialised antennae and males have very elaborate ones. We already know something about this, and when you hum at a group of males, they will come right into your face. So don't sing because they'll go right into your mouth if you do that! Those males are coming at your face because they think you might be a female.

Chris - How are they sensing that?

Gay - It's the vibration of the wing beats of an actual female or the vibration of your hum. It stimulates their antennae and that signal goes to the mosquito's brain and it transforms that into a change in its wing beats moving towards the sound it heard.

Chris - So could you use that as a way of baiting a trap for mosquitoes then? Could you have something that releases a rather aggravating sound that then sucks all the males in, leaving nothing to mate with the females and the population would plummet?

Gay - Yes this is exactly the idea that had come to several scientists a few decades ago and you can build huge loudspeakers and you can pull in millions of males that way. The problem is that it doesn't take many males to be left behind to do the job for the rest of the females.

Chris - But what about the females? Do they not respond in the same way?

Gay - No-one really knew what behaviour there was with females because if you play a sound to them, they don't really change the way that they fly. But it bothered me because we hadn't investigated females very deeply. So I went to see a colleague of mine at the University of Sussex and said 'hey you know about sound, and do you think that it's possible that these two might be able to hear each other?' We did a series of experiments to try and investigate what kind of behaviour the females might have. And indeed we uncovered a lovely duet.

Chris - So you've given me the sound samples. Anyone who is mosquito-phobic or who doesn't like the sound of things that resemble dental drills, you might want to cover your ears. Gay, talk us through this and tell us what they are.

Gay - The first thing to do is to see what two males sound like. So you've got this cloud of swarming males and two males close to each other. That's what we did in our experiment: we tethered two mosquitoes close to each other and we let them listen to each other and recorded what the effect was. So this is what it sounded like when you put two males together.

Chris - So first you hear the first one and then you hear the other one coming in subsequently. Ok here we go.

Gay - That's the first one coming in... and the second one. Now if that doesn't grate upon your ears, nothing will!

Chris - So basically there's just two pairs of wings flapping away there.

Gay - That's right and it's a really discordant sound and it doesn't have anything attractive about it. Now let's do something else this time. Let's start off with the male and then a female comes along. Let's see what that sounds like. Here's the male... and then here's the female.

Chris - So actually they synchronise their wing beats.

Gay - They do. They move towards each other. It's a little hard unless we listen to it again more carefully, but they both move a little bit towards each other and they overshoot and it's a little bit all over the place, but if you give them enough time they get right into the same register.

Chris - So by synchronising their wing beats, one is telling the other that I'm male, and the other is saying that they're female, and they both know that they should pair off. So does then vision take over? Do they get close enough so they can then see each other and then they know who they're dealing with?

Gay - Their vision is not good enough for that. They've got very poor resolution in terms of vision. What I mentioned earlier is that males move towards that source of sound and when their wing beats are flapping at around the same speed, they get in gear and the male catches up and grabs the female. Once this has happened, contact senses take over.

Chris - People probably don't realise quite how hard it is to do and record two individual mosquitoes in an apparatus. How did you do that?

Gay - Well we needed lots of the fine engineering from the University of Sussex Neurobiology department. They have the kind of recording equipment and tiny little microphones that just pick up the sound near where the wing beats are. Then you put a little drop of beeswax on the back of each mosquito.

Chris - It sounds easy but how big is that?

Kat - You're lassoing mosquitoes!

Gay - Yes indeed.

Chris - So the obvious spin off of this as we've already explored, is that it's possible to lure mosquitoes into traps and things. But does this add any additional details that we might be able to exploit in control of diseases like malaria and things like that?

Gay - There's a misconception that you can affect female behaviour with a sound. There are these repellent buzzers that are meant to repel female mosquitoes. We've tested them scientifically and there really isn't much evidence that these work. It's really the upside down version of the story. Males are attracted to females; females aren't really repelled or move about. So this is one kind of product that is slightly misguided in its premise. But the more important thing I was trying to understand is why these mosquitoes can establish themselves in an environment where there are only a few of them left, such as at the end of the season. I wouldn't day there was a good practical outcome to come out of this immediately from sound and mating behaviour, but of course that's only one part into my research into mosquito behaviour, and those are far more applied.

- Could a planet support life without a star?

Life on Earth uses energy either directly or indirectly from the sun. However there are deep sea organisms that live off the energy that ...

Could a planet support life without a star?

People were quite interested in a couple of moons around other planets, for instance, Titan. This is because it has a very large store of organic molecules. Because it's near Saturn, which has a very strong magnetic field, it has the ability to bend and stretch Titan. The strong compression and expansion creates a lot of heat and people think that this might be sufficient to cause water to exist in liquid form in those liquid worlds and they therefore might be a good spawning ground for life. The thing about the hydrothermal vents on Earth is that the life you find there all evolved originally from bacteria that depended on the sun's energy. They then became specialised, rather than being a brand new form of life that just appeared there, which is ever so subtly different. It's perfectly plausible that it might happen on another planet though.

- Does police aggression cause crowd violence?

It's been suggested that the police can trigger a public reaction by being heavy handed. We know that the police tend to be more heavy ha...

Does police aggression cause crowd violence?

That's very much the kind of process that we focus in on. We call it a self-fulfilling prophecy; it's the expectation that a large crowd of supporters is going to cause a problem and then what you do is throw resources at it because you feel you need to control it. The idea is very traditional that the crowd is very irrational and it needs to be controlled. Resources are thrown at it and the expectation of trouble means that the officers are stressed and wearing protective equipment. They're much more likely to lash out and then if a small incident occurs in that crowd, then what we see is what people call a heavy handed reaction, which is basically a large number of officers driving forcefully into the crowd. That crowd contains people that haven't done anything wrong and didn't intend to be involved in violence. They find themselves being physically assaulted and it makes them wonder why they are being treated in that way. This draws people in the crowd into violence when they had no intention prior to police intervention of engaging in violence.


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