 What about intelligent design creationism? How can they be affected by confirmation bias? The strategies are a little different here, because the bias is an intentional act to conceal the shortcomings of an argument based on an ideological position, not scientific evidence. There are a couple of ways they use a selective reading of data to support their positions. One simple way is by quote mining from papers or authority figures. They take only the part of a large block of text that says something they agree with, without acknowledging that the whole statement runs counter to their argument. They're giving a distorted view of what is being said. The off-sided quote from the late-grade Stephen J. Gould about the trade secret of paleontology being the scarcity of transitional fossils seems to suggest that the number of transitional fossils is a weak point of evolution, when in fact Gould was referring to his own theory of punctuated equilibrium, in which isolated populations change morphologies relatively rapidly. Another way they use confirmation bias is what I call nitpicking arguments. In their logical arguments for intelligent design creationism, they have focused on exceptions to rules without providing the context. Their recent touting of evidence showing the Tree of Life model proposed by Charles Darwin as inadequate have focused on the failure of a prediction of the original theory, when we are in fact talking about a very minor effect known as horizontal genetic transmission, where bacteria and some other organisms swap isolated genes between species via plasmids or retroviruses. This is a case of nitpicking, and the data produced in this area, even the data they are citing, does not contradict the common origin of living things. It merely modifies the mechanism. It would seem their strategy here is to selectively reinterpret enough points while ignoring the overall evidence against them to construct a piecemeal argument that supports their ideology. For the last point about ID creationism, I'd like to work from the case of the explanatory filter proposed by philosopher and theologian Bill Dimsky. Bill is an instructor at APTIS Theological Seminary and one of the central figures in ID creationism. Much of his work concerns how we would detect design in living things by intelligent agency if it existed. He obviously has a vested interest in one outcome over the other, and is coming at the scientific process backwards by choosing a conclusion in advance and seeking evidence to support it. But his explanatory filter is an affirmative test, and because there is no way to blind the investigator, the results will always be highly affected by confirmation bias. Are living things complex? Yes, obviously. Are complex things often designed by intelligence? Yes, again, obviously. But what about the null hypothesis? Let's restate the questions for that. Are living things made according to observable natural processes? Yes. Are there any complex things that are not designed by intelligence? Yes. This is another case where he clearly isn't seeking to falsify but to support. If the design were obvious or clearly differentiated from chance occurrences, we would not need some sort of diagnostic test detected. The fact that the null hypothesis that life is not designed has more evidentiary support will automatically call into question any result produced from a biased source. On to my last example, HIV aids denialism. I find this one most disturbing because it has caused so much suffering and death. By some estimates these people have killed hundreds of thousands of people by their misinformation. For those unfamiliar with this group, they deny that HIV is the causative agent in AIDS, and their involvement in politics in South Africa led to thousands of the infected being denied basic therapy. Their arguments have been soundly rejected by the scientific community, but they thrive on the internet and represent an actual threat to public health. Please see these videos for more information about this dangerous pseudoscience movement. The AIDS denialists often use a strategy that is very prevalent in other areas of pseudoscience called the ad hoc hypothesis. Ad hoc means for the purpose. These fallacious arguments are constructed on the spot to gloss over unexpected or unwelcome observations with any explanation that avoids conceding a failure. For example, many denialists insist that AIDS is caused by chemical immunosuppression, especially by amyl nitrate or poppers. When cases are seen in normal healthy heterosexuals, they begin to invent explanations. The person was a secret homosexual or took IV drugs, or they were exposed to a chemical and didn't realize it. Anything to avoid admitting that their explanation is insufficient to explain the origin of the disease. Being confronted with your failures is enough to send some people into a deeper state of denial. This is precisely what happened in a well-documented case. The next deck was Raphael Lombardo, a man in Florida who was homosexual and HIV positive for over a decade. He was a fan of the scientific leader of the denialist movement, Peter Dusberg, a professor at UC Berkeley. Raphael wrote to Dusberg that he was healthy and drug-free, but HIV positive. He took no antivirals, had never used recreational drugs, and didn't even drink. His health was excellent. Dusberg used the content of this letter in his book, Inventing the AIDS Virus. As an example that HIV is a harmless virus, and that it was taking the therapies that caused AIDS, a position he still holds. Raphael died about a year later of AIDS-related complications. What was Dusberg's response? Did he retract his statement? No, he used an ad hoc argument. Here's a quote from a published email he wrote to a colleague. In hindsight, I think his letter was almost too good to be true. I am afraid now he described the man he wanted to be, that he did not use recreational drugs. And his Italian family expected him to be, but not the one he really was. I think he died from Kaposi's. This is such an obvious reversal of position. We begin to see how deeply the confirmation bias affects Peter Dusberg's views. This was a missed opportunity to falsify his position that only people who took drugs or antivirals developed AIDS. Instead, he discounted this evidence with an ad hoc hypothesis, thus ensuring that he never conceded his failure. He has done the same for those who were infected by transfusion, hemophiliacs, newborns, healthcare workers, and married heterosexual transmission. These types of rationalization show that he no longer understands the basic practice of science. The other ad hoc rationalization I can't ignore is the global conspiracy hypothesis. Whenever I refute some point by an althelther or AIDS denialist, I am accused of being a shill for Big Pharma. Anytime they want to discount evidence that doesn't support their view, they proclaim that it is tainted by corporate interests. How convenient this must be. Everyone against you is corrupt. All the data that falsifies your position is fraudulent. When asked why medical science is ignoring these miracle cures, most althelthers will insist that a shadowy, evil agency is preventing the free distribution of these inexpensive products because it would jeopardize their monopoly on healthcare. I'd like to conclude with a warning to those who value science and logic. I've highlighted the pseudo-scientists here, but confirmation bias cuts both ways. We must always guard ourselves from self-deception. Whenever you find yourself employing an ad hoc rationalization, a selective acceptance of evidence, or a positive test strategy, stop and think about this video. Change your thinking and change your methods. Attempt to falsify your position. Set up a null hypothesis and test it. Be honest with yourself about where the evidence seems to point. I'll end with the words of one of the founders of the scientific method, Sir Francis Bacon. The human understanding, when it has once adopted an opinion, draws all things else to support and agree with it. And though there be a greater number and weight of instances to be found on the other side, yet these it either neglects or despises, or else by some distinction sets aside or rejects. Let's endeavor to keep our eyes open. Thanks for watching.