368 • CHAPTER 13 Reasoning and Decision Making
the last chapter of the book, we are now describing a task that involves mental processes
far more complex than judging whether a light has fl ashed, but that illustrates exactly the
same principle: The workings of the mind must be inferred from behavioral observations.
We see, in this controversy over how people deal with the Wason task, how a number
of different hypotheses about what is happening in the mind can be plausibly inferred
from the same behavioral evidence. Perhaps, in the end, the actual mechanism will be
something that has yet to be proposed, or perhaps the mind, in its complexity, has a
number of different ways of approaching the Wason task, depending on the situation.- What is deductive reasoning? What does it mean to say that the conclusion to a syl-
logism is “valid”? How can a conclusion be valid but not true? True but not valid? - What is a categorical syllogism? What is the difference between validity and
truth in categorical syllogisms? - What is a conditional syllogism? Which of the four types of syllogisms
described in the chapter are valid, which are not valid, and how well can
people judge the validity of each type? - What is the Wason four-card problem? Describe the falsifi cation principle. What
do the results of experiments that have used abstract and concrete versions
of the problem indicate about the roles of (a) concreteness; (b) knowledge of
regulations; and (c) permission schemas in solving this problem? - How has the evolutionary approach to cognition been applied to the Wason
four-card problem? What can we conclude from all of the experiments on the
Wason problem?
Inductive Reasoning: Reaching Conclusions From Evidence
In deductive reasoning, premises are stated as facts, such as “All robins are birds.”
However, in inductive reasoning, premises are based on observation of one or more
specifi c cases, and we generalize from these cases to a more general conclusion.THE NATURE OF INDUCTIVE REASONING
In inductive reasoning, conclusions are suggested, with varying degrees of certainty, but
do not defi nitely follow from premises. This is illustrated by the following two induc-
tive arguments:Observation: All the crows I’ve seen in Pittsburgh are black. When I visited my
brother in Washington, DC, the crows I saw there were black too.
Conclusion: I think it is a pretty good bet that all crows are black.Observation: Here in Tucson, the sun has risen every morning.
Conclusion: The sun is going to rise in Tucson tomorrow.Notice there is a certain logic to each argument, but the second argument is more
convincing than the fi rst. In evaluating inductive arguments, we do not consider valid-
ity, as we did for deductive arguments; instead, we decide how strong the argument is.
Strong arguments result in conclusions that are more likely to be true, and weak argu-
ments result in conclusions that are not as likely to be true. Remember that inductive
arguments lead to what is probably true, not what is defi nitely true.
A number of factors can contribute to the strength of an inductive argument.
Among them are the following:- Representativeness of observations: How well do the observations about a par-
ticular category represent all of the members of that category? Clearly, the crows
TEST YOURSELF 13.1
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