Department

PsychologyCourse Code

PSY370H1Professor

John VervaekeLecture

2This

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Review three kinds of theories which are all inter-connected and inter-meshed

Descriptive

Does it exist? Can it be studied scientifically? What are the appropriate conceptual fameowrks

Normative

Generated by rational reflection, layout certain norms that can be used to obtaining truth

Explicit or implicit theory? Is it ecologically or externally valid?

Prescriptive

How can one design and teach?

Often a driving motivation for many psychological researches

Best methods for enhancing learning and transfer

Today

The search inference framework

Computational tradition: thinking=info processing, which is best understood as computation

Newell & Simon (1957)

Gestalt tradition: long debate w/ the search inference

Problem solving = a new search through problem space

Baron (1994) search for 3 kinds of things

1. Possibilities

2. Goals: the criteria by which you can evaluate possibilities

3. Evidence: belief or potential belief that helps you determine how well a possible X can

actually achieve a goal

Inference is the used of evidence to alter beliefs about possibility, goal, and evidence

Judgement is the evaluation of the interconnections between goals and possibility

The nature of search: they argue that problem’s formally represented by 4 kinds of elements

1. Description of initial state

2. Goal state

3. Set of operators, which are actions that can be altered

4. Path constraints, additional constraints on the solution beyond the goal (eg. Finding the

solution using the fewest steps)

A solution = a sequence of operators that can transform the initial state into the goal state while obeying

path constraints

Problem solving method = a procedure for finding a solution

FD =the search space.

F = the number of operators as any step and D = the number of steps

Combinatorial explosion

In order to solve the problem, one has to formulate the problem as such that most of the search space is

excluded

General Problem Solver (GPS)

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Try to develop a GPS that can shed light on how ppl actually solve problems

Research failed because of 2 fundamentally flawed assumptions

1. Problems are in some sense the same and form a unified category, which means that they

share a certain essential features

2. Formulating the problem is an easier job than solving the problem

Why is 1 wrong?

Often, how one solves a set of problem doesn’t transfer to how they solve other problems

Why is 2 wrong?

There are 2 kinds of problems: well-defined and ill-defined. Ill-defined problem means that the

representation of all elements (eg. Path constraints and operators) are incomplete, thus require

reformulation first

Mutilated chess board: almost everyone solves it topographically in the beginning, but once reformulated,

then the problem was solved in 3 steps

Insight: Is it a real psychological construct? Is there even a thing called insight?

The distinction between algorithm and heuristic

Algorithm:

A completely reliable routine or procedure that can be carried in a finite number of steps to solve a

problem

Heuristic:

A rule of thumb that do not guarantee a solution but often help in dealing w/ a problem

Most of our problem solving skills cannot be algorithmic (logical) in nature

Heuristic search: since heuristic doesn’t guarantee a solution, then mistakes are unavoidable

Bias is just a heuristic that showed up in the wrong context

Trial & Error: a myth, human beings don’t actually engage in trial and error

“Hill climbing” heuristic:

You have some way of knowing whether you are getting closer to the goal

(eg. Hill climbing method in dosage prescription by doctor)

Metaphor: the strategy isn’t really realistic, nor is it that powerful and useful

Means-ends analysis:

1. Comparison between current and goal state: identify salient differences between them (how to

identify salience?)

2. Select operator to reduce difference (which requires well-defined operators)

3. Apply operator if possible. If not, select a new subgoal under which the operators can be applied

However, this is recursive because of the problem of infinite regression. The number of attempts at sub-

goal is an ill-defined problem

4. Return to step 1

Productive Heuristics = heuristic procedures that can be used to resolve a problem

Provocative Heuristics = “tickling memory” or insight

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Are productive and provocative heuristics the same?

Kaplan & Simon (1990) argued that the two are the same, though slightly different processes, but “not too

different”

Week 3

Gestalt tradition

• 2 central ideas are that thinking is like perception and that the organizational structure is greater

than the sum of its parts

• the concept of restructuring is central to gestalt’s understanding of problem solving

Thorndike, Edward

• he framed and conceptualized intelligence as the ability to solve problem (which is reasonably

plausible conceptualization according to the prof)

• he tested this idea on cats initially and timed their escape time and the number of trials

• he found that the escaped time decreased with increasing number of trials, however, the graph

was jagged and gradual

• he did not find an insight or revelation where the escape time dramatically decreases in one trial

and form an S-curve

• he thus concluded that everything’s just gradual learning

However, the gestalt tradition challenged 2 things in Thorndike’s conclusion:

1. that problem solving is just bringing past experience into the present

2. that all problem solving all look like the graph Thorndike found for cats

Kohler, Wolfgang

• worked with Chimpanzee “Sultan” in an experiment structurally similar to Thorndike’s and found

that “Sultan” experiences an insight where he just gets it, much like the S-curve of learning

• however, his findings received methodological and cultural criticisms

• he introduced the idea that insight equals to a restructuring of the given material

Duncker, Karl

• coined the term “functional fixedness” in his book “On problem solving”

• in his candle problem, he showed that past experience can hinder problem solving just as easily

as it can facilitate, mainly through the mechanism of “functional fixedness”

• “functional fixedness” describes the difficulties in visual perception and in problem solving that

arise from the fact that one element of a whole situation already has a (fixed)function which has

to be changed for making the correct perception or for finding the solution to the problem

• functional fixedness is also demonstrated in Maier’s 2 string problem (1930) and Duncker’s

candle problem

• Duncker states counters Thorndike and states that functional fixedness is the blinding effect of

prior experience

• thus, problem solving requires a restructuring of problem formulation

• he suggested 2 methods of restructuring:

1. “suggestions from above”

2. “suggestions from below”

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