Given the high
degree of ambiguity present in language, contextual sensitivity
is critical to a full understanding of language. This
is most evident when one examines clinical populations
reported to have reduced sensitivity to context. In the
domain of cognitive neuropsychology, for example, there
are a number of reports that neurological damage to the
right cerebral hemisphere (e.g., following stroke) results
in a reduced sensitivity to contextual information in
language. Additionally, others have found that schizophrenic
patients also have reduced sensitivity to contextual information
present in language (e.g., they consistently misinterpret
double-meaning words [e.g., pen] when the surrounding
sentence context biases less frequent meanings [e.g.,
"When the farmer bought a herd of cattle, he needed a
new pen"]).
What remains
unclear in characterizing the formal properties of contextual
insensitivity in these populations, is a specification
of the component cognitive mechanisms that produce them.
In the domain of cognitive psychology and psycholinguistics,
contextual sensitivity during language processing requires
(at least) two important cognitive components: (1) An
ability to detect contextually relevant information, and
(2) an ability to inhibit contextually irrelevant information.
Contextual failures following right hemisphere damage,
and inschizophrenia, therefore, may not be due to failures
in the internal representation of context, but may be
a by-product of deficient inhibitory processing during
many different levels of cognition.
I argue that
contextual insensitivity following right hemisphere damage
have more to do with failures of detecting contextually
relevant information and less to do with failures of inhibiting
contextually-irrelevant information. In contrast, I argue
that contextual insensitivity in schizophrenia have more
to do with failures of inhibiting contextually-irrelevant
information and less to do with failure of detecting contextually-relevant
information. These claims are based on existing data from
these clinical populations regarding language processing
and inhibitory functioning.
