and even casual observation reveal (see Wolfram, Adger, & Christian, 1999).
To influence speech, instruction would have to focus on speech. Grammar
instruction doesn’t.
Grammar and Logical Thinking. A similar situation exists with regard
to the second assumption. Some people believe that certain logical mental op-
erations are innate. For example, if someone tells us that a friend fell into a pool
of water, we seem to understand intuitively that the friend will be wet. We do
not have to see the person to reach this logical conclusion. But scholars who
study logical mental operations, such as Johnson-Laird (1983, 2001), have sug-
gested that logic is based on experience. In other words, we can logically con-
clude that the person who fell into the water got wet because we have
experience with water and its properties.
Johnson-Laird’s (1983) investigations into our ability to process and com-
prehend logical statements led to a widely accepted model for logical reason-
ing. This model posits that our logical performance depends on a grasp of how
the words in statements relate to the world. Stated another way, our ability to
reason logically depends on our ability to develop a mental model of the rela-
tions expressed in logical statements.
On this basis, we can see why it is rather easy to process syllogisms of the
following type:
All men are mortal. (statement 1)
Socrates is a man. (statement 2)
Therefore, Socrates is mortal. (logical conclusion)We have experience with men and mortality, so we can relate these state-
ments to the world.
However, if we change the wording of a syllogism slightly, such that it is dif-
ficult to develop a mental model of the real-world relations, logical operations
become nearly impossible. Johnson-Laird (1983) found that none of the sub-
jects in his research could arrive at a valid logical conclusion for the following
two statements:
All of the students are athletes.
None of the writers is a student.Many subjects proposed “None of the athletes is a writer,” but that is incor-
rect because some of the writers could be athletes without being students.
Equally incorrect is the conclusion that “None of the writers is an athlete.” The
only valid conclusions are “Some of the writers are not athletes” and “Some of
TEACHING GRAMMAR 21