Now, we have seen that the public does not always follow the advice that is communicated by experts during a disease epidemic. Now, one reason for this is that differences in perceptions of risk can exist, and do exist, between the public and experts. And this is true, not only in the area of health, but in all areas of modern life. Now, the photograph you are looking at is of the Yucca Mountains in Nevada in the United States. Now this area, beautiful, but desolate was meant to be a site where nuclear waste was going to be stored long term. Now, you know one of the problems with nuclear energy is that it does generate waste, which needs to be securely stored to protect people against long term radioactivity. Now, the experts thought that this site here in the mountains would be ideal. It was isolated. They could bury the waste several hundred feet below the ground and people, they thought, would be really safe against the effects of any residual effects of radioactivity from this waste. However, the people in the state of Nevada wanted nothing to do with this nuclear waste repository. And as far as they were concerned, we don't care what the experts say, but this is not safe, and we don't want it. So, that's an example of an issue where technical experts feel that something is safe, but members of the public say no. We're not having any of this. Let me give you another example. Now, this is a clip from the BBC of the H7N9 bird flu. And, which experts feel to be potentially a serious threat, and something that both governments and the public need to do something about. However, it's really hard to get either governmental, or public action long term to do something about H7N9, and why is that? Because here, the experts may feel that the risk is high, but as far as the public is concerned, they feel, no, this is something we can live with, and this is not that urgent an issue. So once again, you see a difference of opinion between experts and the public on what a risk is, how big it is. So, why do these differences in perception exist? Is it because the public does not have the knowledge that experts have? Lots of people think this, but I'm not quite sure that that is true. If you think about it, in our day to day life, we perform actions even when we know that they increase our risk. People smoke even though they know it increases the risk of cancer. We all eat food that tastes delicious, but it's probably not very good for us, and increases our long term risk of obesity, blood pressure, diabetes, and all these other things, but we still do it. And think of another issue, people take risks and smuggle themselves across national borders even though they know they risk death, imprisonment, but they still do it because of the promise that they might be able to lead a better life. All of us, each one of us, we face risks every day in our daily lives, and we negotiate our way around them. We balance these risks, right? There's a difference in the way that technical experts access risk, and the way, so called laypeople, and here it is useful understand that all of us, even though we may be experts in one or two areas, we are laypeople in every other area. So, what is the difference between a scientific assessment of risk and a so-called layperson's assessment of risk? Now, scientific, or expert, or technical assessments of risk have certain characteristics. On the one hand, they're supposed to be scientific based on science, they're probabilistic, they're based on assessments of the magnitude of the severity of the risk, how bad is it going to be, and, the likelihood of this thing actually happening. How likely is it going to be? Experts also talk in terms of comparative risk. Is this risk greater than the other risk? And, if so, is this risk worth taking in order to avoid the other risk? They also talk in terms of population averages, in terms of risk. They talk about risk in terms of one person per hundred thousand. This may be a big risk or a small risk, but these are the kind of figures and concepts that technical expert assessment of risk involves. How do laypeople look at risks? On the one hand, their understanding of risk is intuitive. Just imagine, we're at a road, and we're at a traffic intersection, and there's a little red man blinking away. We look left. We look right; we don't see any traffic, and we scamper across the road, even though the light is red. Why? Because we have made an intuitive assessment that this is a risk that we can take. While expert assessments are probabilistic, laypeople don't have a problem with it. They say, is it going to happen? Or, is this not going to happen? That's what we want to know. Experts may talk about comparative risk, but laypeople are much more interested in things like safety, right? Okay, that may be a comparative risk, but how safe is this for me? Similarly, experts talk about population, the consequences of a risk at the level of the population, laypeople look at it at the level of the individual. How safe is this for me? How safe is this for my family? There are differences in the way that we assess risk. Okay, let's take an example. Let me ask you, what is the risk of a meltdown in a nuclear power plant? Now, if I were to ask a technical expert this, a nuclear engineer, somebody who has a lot of experience in safety regulations, and so on, they might answer something along these lines: They would say, a fuel meltdown might occur once in every 20,000 years of reactor operation. That would be their assessment of risk. But what you and I as laypeople want to know is, hey, tell me how safe, or how risky is it to live near a nuclear power plant? And the answer that you have given me, this expert answer, doesn't really help me to understand anything. This is where we come to the idea of the communication of risk. And, I'd like to introduce you to the idea that risk communication is actually a bridge between these two very different ways of looking at the world that we have seen. On the one hand, the scientific evaluation of risk, a technical evaluation, if you will. And on the other hand, our intuitive understanding of risk. These are different ways of looking at the risk, and we need something to be able to bridge these two ways, and risk communication is that bridge. So, here's what we need to do, here's the next step in a way. Now, if we are to communicate risk, and to act as a bridge between expert assessment, and public perceptions, then we need to understand perceptions of risk.
