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Lecture 12

Cognitive Psychology – Lecture 12 - Lecture Notes.docx

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Simon Fraser University
PSYC 221
Richard Wright

PSYC 221 Fall Semester 2013 Cognitive Psychology: Lecture Twelve Problem-Solving - What is problem solving? (Or what isn’t problem solving?)  You’re not solving a problem if the answer that you are trying to find is immediately apparent  E.g. Asking: “What your mother’s first name?”  it is not really problem solving, because you can access the answer the immediately  Problem solving instead involves a series of stages of processing  When you begin the problem there isn’t a readily apparent solution  E.g. Solving a multiplication problem like 79x23 - You would be mentally carrying digits over and so on - Once you arrive at the answer, and you’re asked the same question again, the second time you answer won’t be considered problem solving, it would just be retrieving the answer from memory from the first time you solved it  Problem solving usually involves a series of intermediate stages of processing Example: “Three Men and a Rowboat” Problem (Well-Defined Problem) - 3 men want to cross a river - They find a boat, but it is a very small boat - It will only hold 200 pounds - Men are names Large, Medium and Small - Large weighs 200 pounds - Medium weighs 120 pounds - Small weighs 80 pounds - How can they all get across? - Clue: They might have to make several trips in the boat - Solution:  Small and Medium cross the river together first  Either Small or Medium return back with the boat  Large then crosses the river alone  Whoever is left over from the first trip, comes back to pick up the other guy  Then both Small and Medium cross the river together again Well-Defined Problems  Constraints are present  There are set of rules  There are conditions that influence what can happen  There are clearly defined information  Like a math problem PSYC 221 Fall Semester 2013  Cryptarithmetic Problems: Constrained by the rules of arithmetic  GERALD + DONALD = ROBERT (D = 5, T = 0, L +1 = R) Some strategies we have work well with ill-defined problems (Means-End Analysis “Reasoning”) Ill-Defined Problems  Usually take longer for us to solve compared to well-defined problems (usually 20 minutes)  Constraints are not present  Example: “When conduct experiments what’s a good variable or measure that we can use to understand problem solving?”  Reaction time (not very reliable)  Verbal Protocol Analysis (not very reliable) - Self-Report  Can’t compare 10 different subjects solving a problem and expect all of them to say the same thing  Not just how the subjects say but also what the experimenter or the tester record this self-report  Depends on interpretation of the experimenter  If you’re forcing subjects to verbalize their process, you might be making them solve the problem different way that they usually do  Cognitive processes happens so quickly that we might not even be aware of it  Not very reliable but still the best that we have, as of yet Difference Between A Well-Defined Problem and Ill-Defined Problem - With the latter we don’t really know what these rules are - We don’t know what the constraints are Part I: Mental Blocks  Sometimes when people solve problems, they are not as efficient as they should be because mental blocks trip them up  Functional Fixedness: You think of something you have as being useful only for its main function  Hints can lessen functional fixedness  If people are stuck trying to solve a problem because they are functionally fixed, this is due to them thinking that the materials they have are only focused on their original uses (a hint can lessen the function fixedness) PSYC 221 Fall Semester 2013  Negative Set: Solving a problem in a way that is less efficient, rather than solving it in a really simple way  Why do people do things in a difficult way?  Sticking to a strategy that has worked in the past but is less efficient than a simpler strategy  Usually these people whom use the negative set usually settle for a way that they first found to complete the task Example: Old Experiment “Candle Problem” (90 years old) - Task: Attach the candle to the wall - Equipment Given: Candles, match box and thumb tacks - Solution: Tack the match box to the wall and then melt the candle wax to the top of the match box and so the rest of the candle can adhere to that - Variations of the Candle Problem  Subjects in one condition were given the materials in boxes  Candles in a box, tacks in a box, matches in a box  Thought of objects in their container role (boxes in their container role “Functional Fixedness”)  Didn’t think that boxes could be used as something else other than a container  Subjects in the other condition were given the materials outside the boxes  Solved the problem faster Example: Two-String Problem (Another Example Similar to the Candle Problem) - Strings coming down from ceiling - Strings are too far apart to be tied together - However, there is other stuff - Tie pliers to one of the strings as a weight and swing the string and then get the other string and tie them together  Pliers are used as a weight rather than a grip  Get subjects to use the pliers as a weight before the task  Hint, become less functionally fixed  Or reverse, have them use the plier to grip and twist something before the task  Become more functionally fixed Example: MacGyver - Opposite of someone who is functional fixed - Always small materials he would carry (string, crocodile clips and etc) Water Jug Problem: B – A – 2C = 100 ml (Desired Quantity)  Negative Set problem PSYC 221 Fall Semester 2013  Three jugs with different capacities and want a certain desired quantity, how do you get it from these three jugs?  Jug A holds 21 ml  Jug B holds 127 ml  Jug C holds 3 ml  Solution: Fill Jug B, Take away water from Jug B by pouring water until Jug A is full and then fill up 2 Jugs C. Nine-Dot Problem:  Draw no more than 4 straight lines (without lifting the pencil from the paper) which will cross through all nine dots  Reason: People don’t solve it quickly because they assume that you’re not allowed to draw outside the perimeter of the nine dots. Matchstick Problem:  Given six matchsticks, arrange them to form four equilateral triangles with each side one stick long.  Solution: 3D Pyramid  Reason: People don’t solve it quickly because they assume that you’re not allowed to think outside the perimeter Part II: Solving Problems with Analogical Reasoning - Problems can be solved successfully with analogical reasoning - One Famous Example: Figuring out how neurotransmitters bind to receptor sites and this made sense when people started thinking about the shape of the receptor site for the neurotransmitter dopamine will be different to the receptor site of different neurotransmitters like norepinephrine or serotonin (Analogy: Lock and Key) - It helped to come up with an analogy in order to understand how this process worked - One Famous Experiment: Study carried out to see if the experimenters could get the subjects to use analogical reasoning  Problem: Tumor Radiation Question – Subjects were told that someone had a tumor in their body (stomach) that needed to be radiated (course of radiation therapy) and that they needed to radiate the area in the body where the tumor was with strong enough radiation to destroy the tumor, but at the same time not damaging the surrounding tissue  Solution: Use multiple beams of radiation aimed at different angles that intersect the tumor at a single point which has higher concentration of radiation that is strong enough to destroy the tumor  Before Task: Fortress Attack Story - Castle with a bad guy inside, good guys looking to attack the castle and defeat the bad guy - Land mines that surround the castle PSYC 221 Fall Semester 2013 - Story Number 1 (Condition 1): Attack from under ground - Story Number 2 (Condition 2): Attacking the castle from all angles - Provided useful analogy - Priming for solving the problem - When people heard Story Number 1 it did not help them come up with a solution, whereas Story Number 2 did (Priming  Reasoning of the Analogy from they use to solve the problem) - Analogical reasoning is good for solving ill-defined problems (E.g. Global Warming and Climate Change) Part III: Solving Problems with Means-End Analysis - When computer scientists wanted to see if they could figure out how to make a chest playing program and other computer algorithms that solve problems  Started talking about Means-End Analysis. - Means-End Analysis
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