The pain of the headache. How common is cynthia. And what's the prevalence in the population. Do we know. Well yes so. This is something. I've spent the last twenty years looking into first estimates for communists were based on awesome citizens to come forward so there was a very nice study by simon baron cohen and his colleagues nine hundred ninety six and they placed an advert in the newspaper in cambridge. Uk and it describes sinister. You added all syntheses to come forward. And he found that the prevalence of this season was one in two thousand from that study now of cools. Unfortunately and of course. They knew this they would be radically underestimating because they were relying on citizens to read the newspaper that day to to read the article to come forward with your lots of things that filter out people through that process so in two thousand and In nearly two. Thousands a michalik jamie ward and i decided to instead of relying on sinister come forward. We started to go out into the gym reputation. We would gather large groups of people together and screen every single one of them on. This gave us a better estimate. Really of the prevalence of citizens asia and since then. I've individually screened. Almost twenty thousand people facilities your and from that. We have a quite a good idea. Bats is at least four point four percent in the population so at least one in twenty three people have sinister in that study. We were looking at around one hundred forty different types of citizens but we had missed out some quite crucial types so we also know independently. This around ten percent of people see time or numbers or letters out in space. Now that would add another ten percent to that figure that i gave earlier. We also know that at least one to two percent of the population have personalities full lettuce numbers days of the week of the year. So we would have to ask data owners well siree but it does really come down to what you think. Steve is if you think these numbers are getting quite high they are but you might want to question where the numbers mapped out in space. Where the time. Touting spice is ministy asia because ten percent of the population experiencing that makes start to well. Is this really sinister Toll but a very simple answer is at least or percent of the population. Now that's an interesting prevalence not feel small. Four point four percent field small but it's actually equivalent entire population of the united states in the world. So if you were to gather sixties together that would be three hundred seven million sinister worldwide. Which is you know similar plating. Usa population service of rare condition but not insignificant. And do you know. Is it more common in men or women or is it equally distributed. Do not so very nice question again. Because it speaks to methodologies so this early study of prevalence could hit by placing advert in the newspaper and asking sinister to come forward. Gave the very very strong impression that it was a female trait. Because i think something like eight times as many females indices found as miles so it put across the message Who was a was a female trae to not stayed with us for about decade however it turns out that that was a trick of the methodology found in the methodology because in fact we know from many other studies that women with unusual conditions are simply more likely to come forward so what we actually have is a condition which is balanced across the sentences. When you go out and screen people through allowed cooperation you find the same numbers might same number of male and female sinister but when you ask them to come forward. The men hold back in the women reach out to scientists. I i mentioned in the introduction than in the past couple of decades scientists have begun using brain scanned understand. What's happening in the brains of people with cynthia. What have they found the brains of people with cynicism look different or function differently from the brains of people who don't have it. yeah. I think brian imaging Has been the most important scientific step forward in two hundred years. I remember giving sesia lectures Talks before the advent of these brain imaging findings and i would spent the entire tool trying to persuade people. Decision was real now somewhere around two thousand five. We got a sudden proliferation of imaging studies and that was wonderful because now when i give sinister tools the first thing i do is show the brain of sinister in an image for example and the brain of control. And they're so very different. That i no longer have to struggle to persuade people on genuineness. So what do they show these. These brain imaging studies show very nicely that the brains of cynicism different to those of people without sinister asia. The different functionalities ephemera. We can see that collective regions or regions close to Areas in the visual cortex will help in response to reading black and white numbers facilities when obviously foot controls. They've same legions would only tell if they were exposed to color in the real world and also some very nice Data from our dutch colleagues showed that have different structural qualities in a brian so differences in that white mataco hurons in different parts of the brain. So right to white matter. Connectivity nikola selective regions for example also interesting differences differences in frontal areas different parietal areas that might be linked to a Binding said finding is where we bring together different features of the world so for example. If i look at a green apple the greenest is in one part of my brain. The shape of the apple is in another part of my brain. The binding region helps to bring those pieces of information together and syntheses have differences in parietal areas that deal with binding almost as if ova binding features that no tiny binding the colors of apples to the shapes of apple. Step finding the color letters and numbers and.