Jelte, welcome! To this last week of our MOOC Solid Science Research Methods. You have the honor of closing the course down. >> Maybe it's a good idea if you introduce yourself to students first. >> Yes. I'm Jelte Wicherts. I'm a associates professor in methodology and statistics at Tilburg University. I did my PHD at the University of Amsterdam in 2007, where I defended my thesis on group differences in intelligence test performance which is a highly contested topic. Because it, it relates to something most people value in Western culture, how well we do on IQ tests. >> Yeah. >> So, people have a lot of well, views on what it means that some people may score lower than others, or some groups may score differently. And this, this was a fascinating topic to study if only because many people have these views. So it's, these are very controversial issues. >> Right. >> And this is a good test in my view on, of how we should operate as scientists, how we should not be quick when we decide what things mean, that we should really be critical of our own ideas. And critical of how we behave as scientists, how we deal with the data. >> Mm-hm. >> How we try to translate ideas to testable hypotheses. And so, I think it's very, it was, this may have something to do with the fact that now I study mostly how researchers behave. So, I shifted by gears somewhat although I do still do intelligence research. >> Uh-huh. >> But I shifted my, my focus towards what we now call human factors in science. Which is basically how scientists behave. How they should behave. And this is something we. >> And how they practice. >> And how they do behave in, in practice. And, and these are not the same. That's that's a clear thing. >> Yes, exactly. >> That the work shows. So, let's start off with an easy example of how researchers should behave. >> Yeah. >> In the first couple of videos, I talk about the importance of recording your data, and the analysis that you perform, and the steps that you take, and the selections that you make. >> Yeah. >> Can you explain why this is important, and, what can go wrong if people don't? >> Yeah, now well of course it starts with, that's part of the course, I guess. With the whole notion of what scientific method is. And it is a very systematic way of trying to test these ideas and a systematic thing is not, it's something we do, because if we don't you can ea, easily fool yourself. So, it starts with the idea that you want to learn from the data. And if you want to learn from the data, you have to make experiments or studies in which you may be proven wrong. This is the ideal world. This is not something we particularly like. If I have an idea so, this is very well it's it's a bit weird that you test your theories by trying to prove yourself wrong, but this is actually how you do it and it's how you should do it. And it's a very important aspect of that endeavor is that you deal with the things that you do in a very systematic way. So, when you collect data. You have to make sure that you as a researcher, or any other thing do not interfere in such a way that you will always be right. So if I, if I have some hypothesis that, that children will behave very badly. After eating ice cream. >> [LAUGH] >> Let's say. and, and I collect data. I start doing a study so I go to the ice saloon or some ice cream shop and I observe the children after eating ice. that's very simple. If you didn't see children acting very badly misbehaving if you will it is very simple then to, to conclude that you're right. That ice cream eating makes children to become very bad ill tempered little person. >> Yeah. >> Now this is a problem if you don't look at it systematically you will easily forget that you don't have a control group. You have to have a control group. You have to, also collect data on children who do not get ice cream. >> Right. >> And you also have to make sure that those who do eat ice cream and those who don't eat ice cream that they are no different a priori. >> Yeah. >> So this is, there, this is where it starts. You have to collect data systematically. This is the data, the core of our endeavour. And we need to make sure that they're there. Not only to prove yourself wrong, but also because you're testing the theories to, to show what you have found to others. You, in a way, try to convince others. And this is what I like about science, you, you not only try to convince yourself, and you're probably already convinced, but you try as I see to, to, to convince your most ardent opponent. >> Right. >> With the data. And you have to then envision and experiment, and do your work in such a way that, even the person who's, completely believes you're crazy and your ideas are absolutely wrong, will if reasonable enough be convinced of what is going on. And you use. >> And you use the data to do that. >> And you use the data. You, you slap them with the data I always say. >> You slap them with the data. >> You slap them that's what we do in science. You present the data and if you slap them with the data in such a way that you well misrepresent the data or that you, you leave out some data. Or you, you analyze the data in 20 ways, and you present only the best result. >> Right. >> And your, your opponent will just laugh you away, and rightly so. He or she will say, well, I don't, I'm not convinced at all, because you've analyzed the data such and such a way. [SOUND]. >> Why don't you do it like this? >> But that requires that the data is available right? >> Absolutely. >> It has to, it has to be kept somewhere. >> It has to be kept and it has to be available for anyone to see. And this is this is the core of science. It has to be open. If I then have to study of the effect of ice cream on children's misbehaviours I have to keep the data and have to open it up. I'm not going to convince any of my opponents if, if I don't, if they keep the data hidden. I mean then it will become a magic show. >> Right. >> That's basically the same. I, I if I do a trick. And pulled the rabbit out of the hats. And then you probably be very skeptical. And if you're not, they're not allowed to, to look into the hat- >> Yes. >> Or behind the curtains there's no way that they will ever be able to convince you. This is not what we do in science. We show everything. We show in order to convince that we're right.