Thinking
Thinking is the attempt to resolve doubt about:
- Actions (decisions, options)
- Goals (values, objectives)
- Beliefs
- Diagnosis
- Hypothesis testing
- Learning
Thinking is one determinant of actions. Others are learning,
reflexes, and emotions.
Thinking = search + inference
Search for:
- possibilities
- evidence
- goals
Diagram of the search-inference framework
Types of models
- Normative
- Standard for evaluation
- What is the right answer for this task? Why?
- Descriptive
- Psychological explanation of departure from normative
- Heuristics, strategies, mathematical models, perceptual principles,
mental models
- "Bias" = systematic and non-normative
- Prescriptive
- Advice or prescription: heuristics, decision analysis
- Designed to increase evaluation by normative standard
- "Irrational" = departure from prescriptive?
Normative models of inference:
- logic
- probability theory
- utility theory
An example of a bias: Outcome bias
A fault condemned but seldom avoided is the evaluation of the
intention of an act in terms of the act's outcome. An agent who
acted as wisely as the foreseeable circumstances permitted is
censured for the ill-effects which come to pass through chance or
through malicious opposition or through unforeseeable
circumstances. Men desire to be fortunate as much as they desire
to be wise, but yet they fail to discriminate between fortune and
wisdom or between misfortune and guilt (Arnauld, 1662/1964,
p. 285)
Item used by Baron and Hershey (1988)
A 55 year old man had a heart condition. He had to stop working
because of chest pain. He enjoyed his work and did not want to
stop. His pain also interfered with other things, such as travel
and recreation.
A type of bypass operation would relieve his pain and increase
his life expectancy from age 65 to age 70. However, 8% of the
people who have this operation die from the operation
itself.
His physician decided to go ahead with the operation. The
operation succeeded.
Evaluate the physician's decision to go ahead with the
operation.
Another item
A 25-year-old man is unmarried and has a steady job. He receives
a letter inviting him to visit Quiet Pond Cottages, where he has
been considering buying some property. As a prize for visiting
the property, he is given a choice between:
Option 1. $200.
Option 2. An 80% chance of winning $300 and a 20% chance of
winning nothing.
He must mail in his decision in advance, and he will be told
the outcome of Option 2 whether he chooses it or not.`
Design issues
Normative model: what subjects think vs. independence of outcome
Within-S transparent vs. within-S hidden vs. between-S
Summary
Normative models are standards:
- Probability, statistics, utility theory
Descriptive models take several approaches:
- Heuristics, mental models, naive theories
Prescriptive models are addressed to different audiences:
- Decision makers, policy makers, teachers, programmers
Creative Thinking
Definition: NOVEL and USEFUL at the time it is created
Examples:
- The wheel
- The printing press
- Abstract expressionist paintings
- Tamiflu
- The vaccine for AIDS (TBD!)
Stages of creative thinking:
- Problem
- Search:
- Possibilities: divergent thinking
- Goals: creativity + other relevant values
- Evidence
- Inference
Example: Finding a creative solution to global warming
- Problem: the earth is getting warmer
- Possibilities
- Prohibiting the consumption of beef
- Turning gyms into energy sources
- Growing CO2-absorbing plankton in the oceans
- Building houses made of woods
- Move to Mars
- Etc.!
- Goals:
- Finding a creative solution
- Preserving life on earth
- Promoting human health
- Winning the Nobel Prize
- Evidence: More less useful solutions
- Inference
Your assignment: A creative solution to healthcare
Assignment 1
Logic: normative model
Alice is to the left of Betty.
Betty is to the left of Carol.
So, Alice is to the left of Carol.
An X can be a Y.
A Y can be a Z.
Therefore, an X can be a Z.
Are these valid?
Descriptive model: Johnson-Laird's theory
all a are b some a are b
all b are c all b are c
a = b = c a = b = c
(b)= c (a) (b)= c
(c) (c)
Conclusion:
all a are c some a are c
More mental models
no a are b some a are not b
all b are c all b are c
a a
----------- -----------
b = c (a) b = c
(c) (c)
a
a (c) a (c)
----------- -----------
b = c (a) b = c
a (c)
-----------
b = c
some c are not a no conclusion
A hard one (from Johnson-Laird)
Suppose that
only one of the following assertions is true
about a specific hand of cards:
1. There is a king in the hand or there is an ace in the hand, or
both.
2. There is a queen in the hand or there is an ace in the hand, or
both.
Which is more likely to be in the hand, the king or the ace?
The solution
There is a king in the hand or there is an ace in the hand, or
both.
There is a queen in the hand or there is an ace in the hand,
or both.
~k and
~a
OR
~q and
~a
Logical attitudes
An engineer, a physicist and a mathematician were driving in the
country when they came upon pasture after pasture with only black
cows in them. The engineer said, "There seem to be only cows
colored black in this area." The physicist said, "That doesn't
quite follow. The only cows we have seen are black." Then the
mathematician said, "I don't think you are right there. The only
cows we have seen are black on one side."
(Submitted by Ed
Howland, ehowland@cyber.net)
Theorem:
A cat has nine tails.
Proof:
No cat has eight tails.
A cat has one tail more than no cat.
Therefore, a cat has nine tails.
Wason's four-card problem (modified)
Rule to test:
If K, then 2.
Which cards must you turn over?
Multi-card task (Beattie and Baron)
Test: If A, then 2.
Which cards would you ask about to find out
whether this rules holds for all the cards?
A response to the multi-card task.
(S is asked to imagine an A on the back of the 3 in the
unnegated 4 card task.)
S: I would just think that there happened to be an A on the
other side.
(S is asked whether an A I and an A3 would be informative
in the unnegated multi-card task.)
S: No. Because... I was looking for A2 only.
E: But your goal is to find out ii the rule is true
or false. If there was A I or A3 in there, would that be
informative...?
S: No.
E: If the agent came back and said there was an A 1
and an A3 in the pouch, do you think that the rule would be true?
S: Yes.
E: You think it would?
S: Yes.
E: Even though there are As that don't have 2s on them.
S: Yes. Because.. the rule says if there is an A then there
is also a 2. It doesn't say there couldn't be an Al or an A3.
Example of Polya's heuristic methods
x
4 - 13x
2 + 36 = 0
Could you imagine a more accessible related problem?
Naive theories (Roncato & Rumiati, 1986)
Wertheimer on understanding
Transfer problems
Kye's method (Ginsberg, "Children's arithmetic")
64
-28
---
Teacher: "You can't take 8 from 4, so ..."
Kye: "Oh, yes you can. 4 minus 8 is negative 4. And 40 and
negative 4 give you 36."
64
-28
---
-4
40
---
36
Another example from Ginsberg
16 16+9=25 (counting out)
+ 9
---
15
I: So when we count we get 25 and when we do it this way
we get 15. Is that okay to get two answers or do you
think there should be only one?
S: (Shrugs his shoulders.)
I: Which one do you think is the best answer?
S: 25
I: Why?
S: I don't know.
I: If we had 16 cookies and 9 more, would we have 15 altogether?
S: No.
I: Why not?
S: Because if you counted them together you would get 25.
I: But is this (points to the answer of 15) right
sometimes? or is it always wrong?
S: It's always right.
Perkins and Baron compared
| Perkins | Baron |
| structure | possibility |
| purposes | goals |
| arguments | evidence |
Summary: Approaches to thinking errors
Insufficient search for alternative models
Heuristics
Naive theories
Failure to understand