128 PSYCHOLOGY
alive—are notburied. If you had any difficulty with either problem it is because of
mental sets. In Problem 1 the mental set is that this is an arithmetic problem. In
Problem 2 the mental set is that this is a problem associated with international law.
In both cases a mental set was created by implication, not by an explicit state-
ment. Consequently, a mental set that interferes with obtaining a solution contains
a false assumption,a belief that is not correct.
A mental set can be given by nature. Consider the Wright brothers attempt-
ing to invent the airplane. They had to break the mental set that wings must flap.
Birds do not have stationary wings like airplanes.(a) A mental set that interferes with obtaining a solution contains a.(b) The idea that wings have to flap is an example of a mental set given by.Answers: (a) false assumption; (b) nature.Functional fixednessexists when there is a need to use a tool or familiar
object in a novel way and one can’t perceive the novel way. Let’s say that a car-
penter needs a plumb line in order to erect a perpendicular two-by-four piece of
wood. He or she can’t find the line in the tool box. Carpenter A might leave the
job and drive somewhere to obtain a plumb line. Carpenter B might improvise a
plumb line by tying a pair of pliers to the end of a string. Carpenter A, who has
both string and a pair of pliers, is displaying functional fixedness because he or she
can only think of using the pliers for gripping, not as a weight.
Functional fixedness is really a special case of mental set. There is often a men-
tal set that a tool is designed for one and only one purpose. And this fixes the
user’s attention on that and only that particular function of the tool.exists when there is a need to use a tool in a novel way and one can’t perceive
the novel way.Answer: Functional fixedness.Logical Thinking: How We Reason
In order to think effectively, it is necessary to think in a logical manner. Logical
thinkingis thinking that employs valid reasoning to reach a correct conclusion.
Logical thinking is the foundation ofrational thought,thought that fits the real
world and allows us to function well in it. There are two basic kinds of reasoning
involved in logical thinking: inductive reasoning and deductive reasoning.
Inductive reasoningis characterized by making observations and gathering
information until a general conclusion is reached. It is the basic method of sci-
ence. About 500 years ago the astronomer Nicholas Copernicus made observa-