Reasoning and Decision making

• Reasoning and Decision Making wiki ch
• So, what is reasoning? 
• Differences between deductive and inductive reasoning? See table
• Deductive: going from general facts or general principles, and conclude more specifics. If the premises are true, the conclusion must be true.
• Inductive reasoning: based on observations of specific cases, and the conclusions are more general. Lead to a conclusion that is probably true (the bread and butter of science and experiments). Based on evidence instead of proved facts.
• Normative vs. descriptive approaches to reasoning.
• Normative approach is based on logic and deals with valid or invalid statements. Normative is saying how people SHOULD think. Here there is a standard of how to do syllogistic reasoning..
• Descriptive is based on how people DO think. People often don’t follow the normative standard.
• So, why do people do so badly in terms of syllogistic reasoning
• Wason Selection Task: 4 cards … following the rules and people do really badly on this task, which is similar to affirming the antecedent.
• The Florida Drinking Age problem : griggs turns that task into real world contexts, and performance is better in the case of real-world items.
• Illustrates that people are not attending to the form as much as the content. Deduction relies on the form of the argument only, not whether it is right or wrong. But, they do respond to the form of the argument when they are in real world terms.
• Perhaps based in an evolutionary preparation for certain things, or a permission schema or a cheater.
• Generally we don’t do very well with deductive reasoning.
• Inductive reasoning: quality of the evidence, number of observations, representativeness of these observations.
• These conclusions are not definitely true, but they become very likely.
• Limitations that people have in inductive reasoning tasks?
• People rely on heuristics: mental shortcut, thinking aid.
• So then there is strong focus on some parts of the evidence (such as things that can be recalled to memory easily) and ignoring others.
• Ex. People being afraid of flying after 9/11, because they could recall easily a time when people died in a plane, but it was still safer
• Representativeness: They can look at someone and ask is he more likely to be a librarian or a farmer? But they are just making their decision on their looks… relying on similarity and neglecting other pertinent information. 
• Conjunction rule: conjunction of two events is never more likely to be the case than the single events alone.
• People are not usually capable of unbiased evidence, and look for evidence of what they agreed with in the first place.
• These are especially important for decision making.
• Have many options and chose from among those options. 
• 3 major approaches: normative, descriptive, prescriptive.
• Normative approach: trying to liken the decision making to some standard or norm, or evaluate it in realation to a norm. Asking, How should they decide?
• Descriptive: how do people make decisions?
• Prescriptive: how can we help people make decisions they way thay should? To improve their decision making. 
• Satisficing: just doing things well enough. Satisfies and suffices.
• A normative approach? => an expected utility. Takes into account the value of an option and the probability of an option.
• So, you have option x y and z
• V(x) P(x), V(y) P(y), P(z) V(Z)
• You calculate based on the value and proability of an option.
• In this model, you would do it perfectly, knowing how much you need or what you want, do the computation thoroughly and see what works best.
• Claims: losses pack more punch than gains.. it effects you more quickly with less.