Review Topics Last Week 1. Falsifiability – in order for a claim to be meaningful, it must be possible to prove the claim false. This is important because a claim must be falsifiable in order to test it. For example, the claim “all chairs are black” is falsifiable and can therefore be tested because we can observe many chairs and if we find one that is any other color, the claim will be proven false. However, if we do not find a single chair that is a different color than black, the claim holds. Conversely, the claim “all chairs have undetectable souls” is meaningless because it is not falsifiable and, therefore, cannot be tested. 2. Theory- a general explanation for a large number of findings in the natural world (eg: Theory of Gravity) Hypothesis- a testable prediction for a specific situation (eg: If I drop this ball, it will fall down to the ground) 3. Ruling Out Rival Hypotheses- A certain hypothesis may seem to be true (remember naïve realism?) but in fact, some other hypothesis that we failed to even consider might be a better explanation for the phenomenon under study. Thus, it is important to consider the multiple possible explanations that could cause a result and test them against one another to see which is responsible for an effect. Occam’s Razor- a helpful rule of thumb stating that if two possible explanations explain a phenomenon equally well, the simpler explanation is usually the one we should select. So the occam’s razor is just a principle that can help us rule out rival hypotheses, based on the complexity of the explanations. A good example here is that of the crop circles. Had people considered just one hypothesis: Aliens, we would never have found those human pranksters who actually made those crop circles. Once we considered the simpler alternative hypothesis: that human pranksters could have made those crop circles, we looked for them and actually found the pranksters. So now you have two competing hypotheses: 1) Human pranksters, and 2) Aliens. Which one do you choose if you don’t have anything else to go by? This is where the principle of Occam’s razor comes in. You know that 1) is the simpler explanation of the two. Occam’s razor just tells you to go for 1) because USUALLY, the simpler explanation is the better explanation. That is just how things have worked so far in the world. So it is a good principle to live by, again USUALLY. 4. If a card has a vowel on one side, then it has an odd number on its other side. Cards you can flip to check this claim: [A] [K] [2] [7] Best Choices: [A] & [2]: For the sake of argument, let us say that the hypothesis is in fact false. Let us say that the 2 card actually has a vowel “E” on the other side of it. Consider the following scenario: [A] [K] [2] [7] : The side facing you. [3] [2] [E] [L] : The other side, facing down.Flipping cards A and 2 are the best choices because the hypothesis can ONLY be proven false if you flip these cards. The reason is, if you only flip the 7 and find the consonant, the hypothesis can still be true. The hypothesis only says that for every vowel, there is an odd number on the other side. It doesn’t say that a 7 (odd number) cannot have a consonant (L) on the other side. So flipping the 7 here is basically useless for our purposes because even if the 7 has a vowel on the other side, it can only “confirm” your hypothesis. It is the same as observing one more white swan without caring to make an observation about the black swan when evaluating the hypothesis that “All swans are white”. So looking under the 7 here is like looking for more white swans. Looking on the other side of 2 is like looking for the black swan. In other words, if we miss out on flipping the 2, we are missing out on crucial information directly relevant to our hypothesis. Our hypothesis explicitly forbids an even number from appearing on the other side of a vowel. So you HAVE to flip the 2 to check because if you find a vowel on the other side, your hypothesis stands falsified. You would miss it if you do not pick the 2. Why Choice [7] is not the best: Many people would test the original claim by choosing to flip over the 7 card because of our confirmation bias (the desire to seek out information that confirms our beliefs) and hope to reveal a vowel on the other side. However, flipping over the 7 card is not the best choice because the result has no way of disproving the claim (i.e. if there is actually a consonant on the other side, the claim is not disproved because the claim only stated that there are odd numbers on the other side of vowel cards, not that there are vowels on the other side of all odd number cards). Remember, we don’t want to be looking for white swans when there is the possibility of a black swan being hidden somewhere because the black swan is the most powerful observation you can make to disprove your hypothesis. That black swan in this example is on the other side of the 2 card!Ch 2 Research Methods - Guided Notes Heuristics: mental shortcut or “rule of thumb” Representative Heuristic: also known as Base Rate: how common a characteristic is in the general population : occurs when we neglect to consider the base rate Heuristic: estimating the likelihood of an event based on the ease with which it comes to our minds Cognitive Biases: systematic errors in thinking Confirmation Bias: tendency to seek out evidence that our position Bias: tendency to think that we knew what would happen all along Overconfidence Bias: tendency to be overconfident in our ability to predict External vs. Internal Validity External Validity: ability to generalize findings to the real world Internal Validity: ability to draw cause-and-effect inferences from our findings Naturalistic Observation: watching naturally occurring behavior in its environment Advantage: High validity Disadvantage: Low validity : examine a single person or small set of persons over a long period of time Advantage: provides proofs- showing that it is