Transcript Document
Thinking, Deciding and Problem Solving
Are we good at it?
Solve it:
• A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?
• A man bought a horse for $60 and sold it for $70. Then he bought the same horse back for $80 and again sold it for $90. How much money did he make in the horse business?
Depends on….
• Type of problem – Is the problem ill defined or well defined? Leading to more or less obvious solutions.
— Is the task presented in a format that fits our strategy?
• Our cognitive resources – How much knowledge do we have, how is the knowledge organized, can we access it?
– Sometimes prior knowledge and experience helps and other times interferes.
Freqs Vs Probs
• We excel at estimating frequencies, defining categories, and making similarity judgments, but we do not make probability judgments very well.
decompressor are needed to see t his picture.
– how often things occur, not how likely – For example, “10 out of every 1,000 women actually have breast cancer.” instead of “1% of women actually have breast cancer.”
Are we THIS rationale?
QuickTime™ and a decompressor are needed to see this picture.
Focus of the class today: Common Errors in problem solving
• We often don’t have the time, energy, or resources to solve everyday problems step-by-step • Emotional information strongly influences our decision making, even when we are not aware of are needed to see this picture.
it.
• Errors in decision making often take the form of biases and heuristic reasoning.
Logic & belief bias • Argument 1: – General premise: Elephants are bigger than mice.
– Specific premise: Dogs are bigger than mice.
– Conclusion: Therefore, elephants are bigger than dogs.
• Argument 2: – General premise: Mice are bigger than dogs.
– Specific premise: Dogs are bigger than elephants.
– Conclusion: Therefore, mice are bigger than elephants
Algorithm
Algorithm
methodical, logical rule or procedure that guarantees solving a particular problem contrasts with the usually speedier –but also more error-prone--use of
heuristics
Heuristics
Heuristics
simple thinking strategy that often allows us to make judgments and solve problems efficiently usually speedier than
algorithms
more error-prone than
algorithms
Thinking
Unscramble
S P L O Y O C H Y G
Algorithm all 907,208 combinations Heuristic How did you solve it?
US?
Heuristics
• Which of the following is the more frequent cause of death in the – All accidents or Strokes? -- How sure are you?
• Which country has the highest population?
– Myanmar or Australia? -- How sure are you?
– Saudi Arabia or Morocco? -- How sure are you?
• Which city has the highest crime rate?
– Manhattan, NYC or Durham NC? -- How sure are you?
• Answers: – Per 1,000: All Accidents (35.9) vs Strokes (61.4) – Myanmar (42 million), Australia (19 million) – Saudi Arabia (23 million), Morocco (31 million) – Manhatten (184), Durham (238)
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Heuristics
– In one chapter of a best-selling novel, would you expect to find more words that end in ing ( —— ing) OR b. have n as the second to last letter ( —— -n-)?
• Availability bias – Vivid Cases are not more frequent!
– People taking advantage of welfare.
Heuristics
– In one chapter of a best-selling novel, would you expect to find more words that end in ing ( —— ing) OR b. have n as the second to last letter ( —— -n-)?
• Availability bias – Vivid Cases are not more frequent!
– People taking advantage of welfare.
Heuristics
• 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 active in the feminist movement.
Heuristics
• Conjunction fallacy –decreasing probability of all things being true of person
Representativeness
Heuristics
My cousin Rudy is a bit on the peculiar side. He has unusual tastes in movies and art, he is married to a performer. He has tattoos on various parts of his body. In his spare time Rudy takes yoga classes and likes to collect 78 rpm records. An outgoing and rather boisterous person, he has been known to act on a dare on more than one occasion. What do you think his occupation most likely is?
Farmer, Librarian, Trapeze Artist, Surgeon, or Lawyer
Representativeness Heuristics
judging the likelihood of things in terms of how well they seem to represent, or match, particular prototypes may lead one to ignore other relevant information
Framing Effects
the way an issue is posed.
If the second part of the horse buying demonstration was about firewood… Examples: What is the best way to market ground beef- as 25% fat or 75% lean? Who should be denied custody versus given?
Sunk-cost fallacy
When people make decisions about a current situation based on what they have previously invested in the situation.
1$ for $5
Confirmation Bias
Confirmation Bias tendency to search for information that confirms one’s preconceptions 2 groups: Group A “Find out if the interviewee is an introvert” -- Group B: “Find out if the interviewee is an extravert”
Other error sources
Overconfidence
tendency to be more confident than correct tendency to overestimate the accuracy of one’s beliefs and judgments
Belief Perseverance
Clinging to one’s initial conceptions after the basis on which they were formed has been discredited.
The Matchstick Problem
How would you arrange six matches to form four equilateral triangles?
Functional Fixedness
tendency to think of things only in terms of their usual functions