A rule that guarantees the right solution to a problem. Usually by using a formula. They work but are sometimes impractical.

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1 Trial and Error Characterized by repeated, varied attempts which are continued until success, or until the agent stops trying. Typically good for problems where you have multiple chances to get the correct solution. However, this is not a good technique for problems that don t give you multiple chances to find a solution. For those

2 Formal Reasoning It is the kind of thinking you find in an intelligence test. The information needed for reaching a solution is specified clearly. There is a single right or best answer. 2

3 Formal Reasoning 1-Algorithm A rule that guarantees the right solution to a problem. Usually by using a formula. They work but are sometimes impractical. Example: To solve a problem in long division you just apply a series of operations that you have learned. 3

4 Formal Reasoning 1-Algorithm Algorithms, which are very time consuming, exhaust all possibilities before arriving at a solution. Computers use algorithms. S P L O Y O C H Y G If we were to unscramble these letters to form a word using an algorithmic approach, we would face 907,208 possibilities. 4

5 Formal Reasoning 2-Logic Deductive Reasoning Drawing conclusions from a set of observations or premises. If the premises are true, the conclusion must also be true. Inductive Reasoning Draw conclusions but could be conceivably wrong. You draw specific conclusions from general premises. 5

6 Formal Reasoning 2-Logic Deductive Reasoning Inductive Reasoning Example: All human beings are mortal. I am a human being. If the premises are true Then, I am mortal. Example: Most people with season tickets must love music. John has season tickets. Then, John probably loves music. 6

7 Formal Reasoning 2- Logic Deductive Reasoning Examples: 1. All oranges are fruits 2. All fruits grow on trees 3. Therefore, all oranges grow on trees The soccer game is on either Thursday or Friday. I just found out that the game is not on Thursday, so the game must be on Friday. If the two premises really are true, then there is no possible way that the conclusion could be false. Inductive Reasoning Example: All the tigers observed in a particular region have yellow black stripes, therefore all the tigers native to this region have yellow stripes My dog has never bitten me, so dogs don t bite. Even if all the premises are true, it is still possible that the conclusion is false.

8 January has always been cold here in Siberia. Today is January 14, so it is going to be another cold day in Siberia. This argument is inductive. The premises makes the conclusion likely, but they do not guarantee that the conclusion is true. To put the point another way, it is possible that the premises of this argument could be true and the conclusion could still be false. One can, for example, imagine a freak warm day in Siberia on January 14.

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10 Informal Reasoning In informal reasoning problems, there may be no clearly correct solutions. Disagreement may exist about basic premises. Information may be incomplete. Many view points may compete. 10

11 Informal Reasoning 1-Heuristics A rule-of-thumb strategy that often allows us to make judgments and solve problems efficiently. Who would you trust to A short cut (that can be baby-sit your child? prone to errors). Examples: A doctor who wants to determine the best kind of treatment. A factory owner who wants to boost production.

12 Heuristics S P L O Y O C H Y G S P S P L Y O C H Y O C L H O G Y Put a Y at the end, and see if the word begins to make sense. 12

13 Informal Reasoning 2-Dialectical Thinking Consider thesis and antithesis simultaneously to arrive at synthesis. (most advanced critical thought process.) Example: It is what juries are supposed to do in order to arrive to a verdict. You consider argument for and against the defendant s guilt. You consider point and counter point. 13

14 Barriers to Reasoning What are some obstacles to problem solving?

15 Barriers to Reasoning 1- Availability Heuristic Exaggerating the Improbable Estimating the likelihood of events based on their availability in memory. We assume such events are common. Vivid cases in the news often cause an availability heuristic. Example: If it happened in the past, then it will happen now. I had an accident on the freeway, then I can t drive on the freeway because I will get in an accident. (The memory of the accident is the most available. ) 15

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17 Does this look good? Wait, what??? P R O T O T Y P E

18 Barriers to Reasoning 2- Representativeness Heuristic Who went to Harvard? My friend Dan is a smart dude, but did not go to Harvard (but he looks like he did). If I tell you that Sonia Dara is a Sports Illustrated swimsuit model, you would make certain quick judgments (heuristics) about her like about her interests or intelligence. She is an economics / human evolutionary biology major at Harvard University. Judging a situation based on how similar the aspects are to the prototypes the person holds in their mind. Like thinking everyone from Decatur is preppy, or someone with glasses is nerdy, or a blonde is not smart.

19 Representativeness Heuristic Linda is 31, single, outspoken and very bright. She majored in philosophy in college. As a student, she was deeply concerned with discrimination and other social issues, and she participated in antinuclear demonstrations. Which statement is more likely? a. Linda is a bank teller b. Linda is a bank teller and a feminist activist. 19

20 The Availability and Representativeness Heuristics

21 Barriers to Reasoning 3- Framing and the Tendency to Avoid Loss How an issue is framed can significantly affect decisions and judgments. Examples: If you take chemotherapy, you ll lose your hair. (People will respond cautiously) If you take the medication for high blood pressure, you ll be OK. (People will go for it) 21

22 Barriers to Reasoning 4- Confirmation Bias We are much more likely to notice information that supports our beliefs than we are to notice information that contradicts it. Examples: A reporter who is writing an article on an important issue may only interview experts that support her or his views on the issue. One who believes in astrology will believe when the horoscope is right and ignore when it is wrong. 22

23 Barriers to Reasoning 5/6- Belief Bias / Belief Perseverance Our beliefs are, once established, likely to continue. (It's hard to get people to change their minds about candidates, sports teams, musical groups, abortion, etc.) In part, belief perseverance is maintained because of confirmation bias and belief bias. Examples: You continue smoking even though research shows it is definitely connected to lung cancer. You hear that Amy Gadala is talking smack about you, so you think that Amy is a jerk. Later you find out that she wasn t talking smack about you. You may find it hard to shake your feeling that Amy is a jerk. 23

24 Belief Perseverance All Cowboy fans who still believe that things are going to get better are suffering from belief perseverance. Seriously, there are people who refuse to believe the moon landing happened, that Elvis is dead, or that the holocaust occurred. These people continue to hold on to their belief, even with mountains of evidence to the contrary. Their belief perseveres

25 Barriers to Reasoning 7- Fixation or Mental set An inability to see a problem from a fresh perspective. When a person approaches a problem one particular way, usually a way that has been successful in the past. (rigidity.) The Matchstick Problem: How would you arrange six matches to form four equilateral triangles? 25 From Problem Solving by M. Scheerer. Copyright 1963 by Scientific American, Inc. All Rights Reserved.

26 The Matchstick Problem: Solution From Problem Solving by M. Scheerer. Copyright 1963 by Scientific American, Inc. All Rights Reserved. 26

27 The Mind Can Refuse to Make Connections Q. How do you put a bear in a refrigerator? A. Open the door, put the bear in, close the door. Q. How do you put a lion in the refrigerator? A. Open the door, take out the bear, put the lion in. Q. Noah is hosting an animal conference. All animals but one attend. Which one? A. The lion who is freezing his butt off in the refrigerator Q. You want to cross a river that is inhabited by crocodiles. How do you do it? A. Swim across the crocs are at the conference.

28 Mental Set Using no more than four lines, can you connect all nine dots without lifting your pencil from the paper? 28

29 (Mental Sets Continued) Tendency to fall into established thought patterns. Most people will use solutions or past experience to try to solve new problems ( they think "what worked in the past is bound to work now"). To overcome mental sets you must think outside the box literally!