字幕表 動画を再生する 英語字幕をプリント Hi, I'm John Green, and this is Crash Course: Navigating Digital Information. When you were a kid, did you ever hear the phrase “Because I said so”? Like, I most often say that after my kids ask why they can't have m&Ms for dinner. The answer to which, of course, is “you will get scurvy if you eat that way.” But that just leads to more questions about scurvy, and them begging to take a multivitamin so they can eat M&Ms--It's because I said so! I say this because it gets results. You listen to your parents because, you know, they're your parents. And also because they can take your phone away. But as you grow older, “because I said so” no longer cuts it. If you told your boss you deserve a raise “because I said so” you're liable to get fired. Also, I can't afford raises, Stan. Do you think my fleet of lamborghinis pays for itself? I've said it before and I'll say it again, if you want a raise, you need to learn how to change the oil in a lamborghini. NO! You need to provide evidence that you deserve the raise, and that evidence needs to be convincing. And that's how online information works, too. Not only should you look for reliable sources of information, but they should provide convincing evidence for their claims. Solid evidence, ideally. And often, they don't. So today we're going to focus on how to tell good evidence from bad evidence, and maybe importantly, how to identify “Fine but that doesn't actually prove your point” evidence. The stuff that the internet is built on. INTRO In the past few weeks, we've learned how to ask and answer the questions “Who said that and why?” when we encounter new online information. But those two questions alone aren't enough to properly evaluate information. We need to add another question to our repertoire: “What is the evidence?” Why do we need evidence? Can't we just find a trustworthy source and believe whatever they say? Wouldn't that just be, you know, easier? Well, yes, and it's important to find and trust reliable sources of information, the credibility of their claims depends on the evidence provided to back them up. Evidence could be anything, really -- text, photos, videos, data -- as long as it supports a claim and gives you a good reason to believe it's true. If someone is making a factual claim -- and not just voicing a subjective opinion -- then they need to provide proof in order for us to believe it. This classic tweet by comedian Nathan Fielder explains it all. In the photo you see Nathan laughing, looking off camera. The tweet reads “Out on the town having the time of my life with a bunch of friends. They're all just out of frame, laughing too.” To ruin the joke by explaining it, Nathan probably isn't out on the town with friends, otherwise, he would show them laughing instead of this lonely selfie. It's funny because the evidence doesn't back up the claim. But often, when the evidence does not back up the claim, it's not funny. It's just misinformation. Or disinformation. As you probably know from just existing on the internet, it is really easy to hop online and make any claim you want. Like, I know this is going to sound wild, but you can literally type anything you want into this box and click tweet, and share it with the world. Like, the only thing this box will not publish to the public is a thought longer than 280 characters. What a system! But the same is true across social media: Politicians claim their opponents are bad choices for government on facebook. Conspiracy theorists take to YouTube to falsely claim the Earth is flat. Celebrities use Instagram to claim they lost weight using lollipops. And of course, on Tumblr everyone is claiming that your fave could never, and/or is problematic. If a source provides no evidence at all to back up its claims, we should be suspicious immediately. I mean, without evidence, we have no way to know if its claims are true -- and thus no reason to believe that they are. For instance, take a look at this Facebook post that went viral in the summer of 2018. It was shared 1.5 million times. It says, “New Deadly Spider Spreads Across USA The Spider From Hell. Five people have died this week due to the bite of this deadly spider. This spider was first seen in South Carolina in July. Since then it has caused deaths in West Virginia, Tennessee and Mississippi. One bite from this spider is deadly. U.S. Government working on a[n] anti-venom. At this time please make your family and friends aware.” The source is a seemingly random Facebook user you don't know. Although many posts you'll encounter on Facebook are from friends or friends of friends, you'll also find posts from strangers. And if they're not public figures, you may not be able to verify their identity outside of Facebook. So, to determine if their information is trustworthy, we need to look at the evidence. The post features photos of an admittedly terrifying-looking spider. But it doesn't include any other evidence. It doesn't say what type of spider this is, where it typically lives, or how it traveled from South Carolina to West Virginia without visiting Virginia. Wait! Maybe it's a flying spider. Stan, are we sure that this deadly flying spider isn't real? There are also, tellingly, no links to the news stories about the deaths that this spider supposedly caused, because you know, there weren't any. Also, there is nothing to suggest the government is studying an antidote. Or for that matter, A antidote. Now, fact-checking site Snopes.com debunked this all pretty easily. They searched reputable sources for deaths attributed to this spider and found nothing. They also found the person who initially posted this hoax has started other hoaxes in the past. In this case, the lack of evidence was reason to be very suspicious. We didn't necessarily need Snopes to tell us there's no deadly spider taking over the American south, but it is nice to be able to confirm our suspicions with another party. But of course, the mere existence of evidence is not enough to verify a claim, though. For instance, Oklahoma Senator James Inhofe once brought a snowball onto the Senate floor in order to disprove global warming. It was February 2015 and he said that scientists had claimed 2014 was the warmest year on record. Then he pulled a snowball out of a plastic bag and threw it on the ground. Inside the Senate. He was trying to use the snowball as evidence that the planet was not getting warmer because it was cold in Washington, DC -- because you know, it was winter. But we know, thanks to science, that winter continues to exist in many parts of the world, but at the same time, the planet as a whole is also warming. A snowball does not disprove climate change any more than a heat wave proves it, because weather is what happens every day in the atmosphere, and climate is what's happening overall. And what's happening overall is that things are getting hotter. For another example, in 2017 a conspiracy theory cropped up on anonymous Internet message boards claiming the United States Department of Justice was secretly investigating a global pedophile ring. The so-called evidence for this included pictures of Hillary Clinton, her daughter Chelsea Clinton and Sen. John McCain wearing boots for foot injuries at different times. The boots were supposedly covering up ankle monitors tracking them all during the investigation. But, of course, all those photos actually prove is that feet are kind of easy to injure. And get easier to injure as you age. All of which brings me to perhaps the most important lesson of this episode: Not all evidence is created equal. The evidence a source provides should come from another reliable source. And if you find yourself starting to believe complicated conspiracy theories, which, by the way, I think we all do on the internet in 2018, you need to ask yourself, “does this information really make sense, or am I just making it make sense in my brain?” And two, perhaps more importantly, 'does this information confirm my pre-existing world view which makes me pre-disposed to believing it?' Take this Axios report with the headline “Climate change may boost pests, stress food supplies.” It says the global climate change could make millions food insecure in the future. The article goes on to cite the findings of a new study from researchers at the University of Washington, Stanford University, University of Vermont, and University of Colorado. That study was published in Science, which some quick lateral reading can tell you, is a well-respected peer reviewed journal, god I love lateral reading. But they didn't just cite that one study. Axios also provided context in the form of a Harvard study published in a different peer-reviewed journal and comments from a scientist not involved in either study. In other words, they showed their receipts. So really, a search for reliable information online is a search for reliable evidence. Let's take a closer look in the Thought Bubble. OK. Imagine this post pops into your news feed: I can't believe the mainstream media is hiding this story. The moon landing was fake this whole time. It's accompanied by an image from the 1969 moon landing and includes a link to a video called: Were the moon landings faked? At face value, this post is claiming that the U.S. government never actually sent astronauts to the moon in 1969. The evidence provided is a video purporting to explain how they deceived the public. But the presence of evidence, here in the form of a video link, does not guarantee the claim's validity. If you follow the link, you'll find the video in question belongs to a channel called “Alltime Conspiracies.” It's a channel is filled with videos about conspiracy theories and supposed cover-ups, like “10 real life vampires.” Not exactly a trustworthy source. There have only been 4 vampires in real history. The video itself points out both what conspiracy theorists have said about the moon landing and what official sources have said. But the video is structured to make you think some questions have been left unanswered. YouTube has also added an information panel to the video that points to the Encyclopedia Britannica article on the Apollo Space Program. Because YouTube wants you to look for information from other sources, especially around topics that are prone to misinformation. But let's be clear: the moon landing definitely happened. And for it not to have happened, a conspiracy would have needed to involve thousands of people. Thousands of people never conspire to do anything secretly. The video may have looked interesting, but if you check the evidence, you will see how clearly wrong the post is. Thanks, Thought Bubble. So sometimes, the source of evidence for a claim will be reliable, it just won't exactly be relevant to the argument. Like, say you read a story online about how e-cigarette companies are marketing their products to be attractive to teens. Someone has commented on it, saying “It's totally safe for kids. After all, they help people stop smoking, don't they?” But wait a minute. What does smoking cessation have to do with kids using e-cigarettes? Nothing. This is a classic case of utilizing evidence that may be relevant to the broader topic of conversation -- in this case, e-cigarettes -- but doesn't actually have any bearing on the claim at hand -- that e-cigarettes are safe for kids. And the use of irrelevant evidence like this can be a big obstacle when evaluating online information. Because not only must you determine whether a source sharing information is credible, you also have to determine whether they've provided evidence and whether that evidence is credible. And this irrelevant evidence or evidence that doesn't quite make the right point is all around us online. One very popular form of irrelevant evidence is the spurious correlation. A spurious correlation is the implied causal relationship between events that are coincidentally linked. And this happens constantly with data. For instance, there's a strong correlation between the number of people who drown by falling into a pool every year and the number of films that Nicolas Cage appears in that year. But Nicolas Cage movies do not, like, throw people into pools, because CORRELATION IS NOT CAUSATION. For instance, plenty of blog posts and misleading news articles have incorrectly implied a connection between the rate of vaccines given to children and the rate of autism diagnoses. In the past few decades, the number of vaccines recommended for kids has gone up as new medical discoveries have been made. The prevalence of autism spectrum disorder has also increased over the past few decades. Despite bountiful scientific evidence showing there is no link between these two facts, many continue to believe and use the web to spread the idea that vaccines “cause” autism. In fact, they've been so successful in spreading this spurious correlation that a drop in vaccination rates and an outbreak of measles swept through Europe in 2018. So this is not only about spiders that don't exist. This is, in some cases, a true matter of life and death. Interrogating the evidence our online sources provide us is incredibly important. We need to ask whether that evidence is reliable and whether it actually backs up the claim being made. The quality of our evidence, like the quality of our information, effects the quality of our decisions. And also the prevalence of measles. We'll dig even deeper into evidence next week. I'll see you then.