C81COG: Cognitive Psychology 1

1. C81COG: Cognitive Psychology 1 THINKING AND PROBLEM SOLVINGDr. Alastair D. SmithRoom B22 – School of Psychologyalastair.smith@nottingham.ac.uk

2. Student evaluation of teaching • The forms that I have distributed are part of the University's Student Evaluation of Teaching (SET) process. They provide an opportunity for you to evaluate my teaching in this module in TODAY’S LECTURE. You can make specific suggestions and constructive criticisms in your own words in section C on the second side. Note that the forms are anonymous. • Your opinions are taken very seriously and SET results are weighed in decisions regarding the career development of academic staff. The results of Sections A and B are processed centrally and the forms are returned to teachers to consider section C comments. However, any forms containing offensive remarks are ignored and destroyed. • May I ask for a volunteer whose job will simply be to collect the completed forms, place them in this envelope and hand it in to the School Office.

3. Introduction Lecture 18: Thinking and Problem Solving Lecture 19: Deduction and Induction Lecture 20: Syllogistic Reasoning Lecture 21: Probabilistic Reasoning

4. Introductory reading • Eysenck, M.W. (1993). Principles of Cognitive Psychology. • Chapter 6 • Eysenck, M.W. (Ed.) (1998). Psychology: An Integrated Approach. • Chapter 8. • Eysenck, M.W. & Keane, M. T. (1995). Cognitive Psychology: A Student’s Handbook. • Chapters 15, 16 & 17. • Anderson, J. R. (1995). Cognitive Psychology and its Implications (4th Edition) • Chapter 8.

5. Lecture 17: Thinking & Problem Solving Aims • In this lecture I will introduce a selection of key historical experiments on problem solving Learning Objectives • After this lecture you should be able to: • Distinguish between Gestalt and Behaviourist approaches to problem solving, providing examples. • Describe Wallas’s stage theory of problem solving. • Define and describe evidence for the existence of incubation and functional fixedness in problem solving. • Contrast situations where feelings-of-knowing or feelings-of-warmth are accurate with those where they are not.

6. What is a problem? • “A problem arises when a living organism has a goal, but does not know how this goal is to be reached” (Duncker, 1945) • A problem could therefore be said to have three crucial elements: • A starting state • A goal state • A set of processes (usually called operators) that can transform one state into another • “…the psychologist must devise tests or experiments in which his subjects are required to ‘think’ and in which they can be observed and the factors involved in the situation isolated for scrutiny. This is a tall order.” (Thompson, 1959)

7. Two historical approaches • BEHAVIOURIST • The study of behaviour as objective and observable • Most appropriate unit of analysis is simple stimulus-response association • Problem solving occurs through trial and error processes • GESTALT • Problem solving is more than reproduction of learned response • Occurs through a process of restructuring and insight – Aha!

8. Thorndike (1898): The behaviourist approach • Prior to Darwin it had been thought that the minds of humans and animals were fundamentally different. • Darwin argued instead that the minds of humans and animals were (on the basis of the evolutionary chain) fundamentally similar. • Thorndike was concerned with problem solving (and other higher cognitive functions in animals).

9. Thorndike (1898): The behaviourist approach • Thorndike placed cats in a puzzle box with a clasp to hold the door shut • The door could not be opened without the cat performing a sequence of actions • Thorndike plotted the time it took for the animal to solve the problem as a function of the number of opportunities

10. Thorndike (1898): The behaviourist approach

11. Thorndike (1898): The behaviourist approach • Thorndike’s cats learn to escape from a “puzzle box’ by a process of trial and error, eventually pulling the correct string. • Although the initial escape is initially by chance behaviour. Future escapes become progressively faster as the connection between behaviour and reward is learned. • The key finding is that problem solving was incremental rather than insightful. • “The cat does not look over the situation, much less think it over, and then decide what to do. It bursts out at once into activities which instinct and experience have settled on as suitable reactions to the situation…it does not ever in the course of its success realize that such an act brings food and therefore decide to do it and thenceforth do it immediately from decision instead of impulse.” (Thorndike, 1898, p. 45)

12. Köhler (1925): The Gestalt approach • After the work of Thorndike many scientists thought that animals could only learn through trial and error. When an animal faced a problem, such as finding food, it would stumble around until it hit upon the right answer by trying different actions until it got lucky • An alternative viewpoint came from Köhler (1925), German Gestalt psychologist trapped on Tenerife during WW1. • Found a colony of chimps and passed the war studying their problem solving behaviour • He believed that animal thought, especially that of chimps, was more complex than most people imagined. Responses necessary in the puzzle box were unfamiliar, so the cat could not perceive a mechanism

13. Köhler (1925): The Gestalt approach • Of the chimps Sultan was clearly his best (or favourite) subject. • One problem was to get some bananas that were outside his cage and beyond the reach of his arms. • If Sultan was given a stick that was long enough he would immediately use it to reach the bananas. • However, if he was given two sticks, neither of which were long enough he would at first try, then give up and sulk. After a period of time he suddenly went to the poles and placed one inside the other creating a pole long enough to reach.

14. Köhler (1925): The Gestalt approach

15. Köhler (1925): The Gestalt approach • Learning seemed to be the result of a sudden insight rather than incremental trial and error • The moment the correct solution is detected performance is perfect • So why the difference? • Thorndike’s cats were hungry and distressed Köhler’s chimps were well-fed and cared for, and free to roam • We now know that Primates are closer to humans in terms of their genetic structure, social structure, and share many cognitive abilities

16. Wallas (1926): Four stages of creative thinking • Preparation: A problem is formulated and initial attempts are made to solve the problem. • Incubation: The problem is set aside and no conscious work is done on it. • Illumination: A sudden inspiration provides a new insight into the way in which the problem might be solved. • Verification: Conscious work on the problem develops and tests the inspiration to provide a full solution to the problem. • The importance of insight has been formalised into accounts of creativity :

17. Wallas (1926): Four stages of creative thinking • These stages appear to be characteristic of some scientific discoveries: • German physiologist and physicist Helmholtz described how “happy ideas come unexpectedly, without effort, like an inspiration.” • British mathematician Hadamard (best known for his proof of prime number theory) wrote “unconscious activity often plays a decisive part in discovery; that periods of ineffective effort are often followed, after intervals of rest or distraction, by moments of sudden illumination.” • …but is there really any evidence that incubation is actually useful?

18. Initial State Goal Silveira (1971): The cheap necklace problem • “You are given four separate pieces of chain that are each three links in length.  • It costs 2¢ to open a link and 3¢ to close a link.  • All links are closed at the beginning of the problem.  • Your goal is to join all 12 links of chain into a single circle at a cost of no more than 15¢.”

19. Silveira (1971): The cheap necklace problem • Control group: Worked on the problem for half an hour • 55% solved the problem • Experimental group 1: Worked for half an hour, interrupted by a half-hour break in which other activities were performed • 64% solved the problem • Experimental group 2: As 1, but with a 4 hour break • 85% solved the problem

20. Murray & Denny (1969): When is Incubation necessary? • Murray & Denny attempted to find further evidence for incubation and to explore when it is necessary for problem solving. • Subjects were divided into high and low ability groups on the basis of their performance on a ‘use of objects test’ of creativity. • Subjects were then given 20 minutes to solve a complex practical problem (moving steel balls into a metal cylinder without getting within 8 feet of the cylinder). • Half the subjects had a 5 minute break in the middle of the task, and half didn’t.

21. Murray & Denny (1969): When is Incubation necessary? • Murray & Denny suggested that incubation was only useful for problems that people find hard • For the high ability subjects for whom the problem was relatively simple the distracter task acted as a distraction from the problem at hand • The low ability subjects for whom the problem was relatively hard were aided by the distracter task – they required a period of incubation

22. Barriers to success • Functional fixedness • People fixate one a property of the problem and cannot think about it in a different way • Mental set • learn a particular way of solving a problem which often produces success, but continue to use it even when inappropriate

23. Dunker (1945): Functional fixedness • “Support the candle on the wall so that it doesn’t drip on the table below” • Subjects often tried to nail the candle to the wall or glue the candle with wax

24. Dunker (1945): Functional fixedness • “Support the candle on the wall so that it doesn’t drip on the table below” • Subjects often tried to nail the candle to the wall or glue the candle with wax • Dunker subjects are fixated on the box’s normal function of holding nails – unable to re-conceptualise it as a candle holder. • Becomes easier if the drawing pins are emptied out of the box before the subject arrives

25. Luchins (1942): Functional Fixedness & Einstellung • Another case of fixedness or problem set is found in the water-jug problem. People may become biased by experience to prefer certain approaches, which may block the solution— the einstellung effect (mechanization of thought). • Luchins’ (1942) water-jug problem. Each problem specifies the capacities of jugs A, B, and C, and a final desired quantity. The task is to use the jugs to measure out the final quantity.

27. Luchins (1942): Functional Fixedness & Einstellung • Another case of fixedness or problem set is found in the water-jug problem. People may become biased by experience to prefer certain approaches, which may block the solution— the einstellung effect (mechanization of thought). • Luchins’ (1942) water-jug problem. Each problem specifies the capacities of jugs A, B, and C, and a final desired quantity. The task is to use the jugs to measure out the final quantity. • Most problems can be solved using the same pattern, but there are more efficient solutions to problems 7 and 8.

28. Luchins (1942): Functional Fixedness & Einstellung • In one condition (SET) subjects received a set of problems with a similar hard solution method. • In another (control) subjects received a set of problems to be solved using simple but different methods. • Next, subjects were given the water jug problem. • SET subjects persistently tried to apply the hard method that they had been applying to the previous problems. They were ‘set’ on using that solution and could not see the easy one. • Control subjects readily applied the easy method.

29. Overcoming fixedness – the nine dot problem • Draw four continuous straight lines connecting all the dots without lifting your pen from the paper (Scheerer, 1963). • According to Scheerer most people cannot solve this because they assume (are fixated) in believing they must stay within the square.

30. Overcoming fixedness – the nine dot problem • However, not all insight problems are instantly solved when fixedness is overcome. In the nine dots problem many subjects require more than one hint to arrive at the solution (Weisberg & Alba, 1981) • Stress the importance of recalling past experiences of problems similar to the one trying to be solved – restructuring as one works through the problem (rather than ‘insight’) • So is there really such a thing as an ‘insight problem?’

31. Feeling of knowing • Even when we cannot solve a problem immediately, we sometimes feel closer to the solution than at other times. A classic example is the “tip-of-the-tongue phenomenon” • Brown & McNeill (1966) - what is the word for “a navigational instrument used in measuring angular distances, especially the altitude of the sun, moon and stars at sea?”. When people claim the answer is “on the tip of their tongue” they are 57% correct in identifying the first letter of the word. • But feelings of knowing the answer may not always be accurate: Metcalfe (1986) compared feelings-of-knowing for general knowledge questions, with feelings-of-warmth for insight problems. While feelings of knowing appeared to predict subsequent recognition of the answers, feelings of warmth did not predict subsequent solution.

32. Feeling of warmth Incremental - e.g. Tower of Hanoi • Feelings-of-warmth can sometimes predict how close to solution you are. This seems to be the case when incremental solutions are required rather than insight solutions (Metcalfe, 1986; Metcalfe & Wiebe, 1987). • Metcalfe’s studies allow an experimental way of measuring the phenomenon of insight. Insight - e.g. Reversing Triangle

33. Sample exam questions • Thorndike found that cats solved the problem of attempting to escape the puzzle box by: • Trial and error • Insight • Incubation • Einstellung • Wallas’s four stages of creative problem solving are: • Conception, incubation, illumination, verification • Preparation, incubation, illumination, verification • Preparation, incubation, insight, verification • Conception, incubation, insight, verification