Figure 3.1 Some important regions of the human brain (left view of left
hemisphere)understand normal speech, comes in a great variety of forms. It is well
known that Broca’s area, a region of the brain close to the SylvianWssure in
the left hemisphere (seeWgure 3.1), seems to be important for grammatical
processing. This is an area which brain-scans show to be activated when
people are reading or listening to something in a language that they know.
Patients suVering damage in this area are liable to suVer fromBroca’s
aphasia, characteristically producing slow and ungrammatical speech. Yet
damage to an area on the other side of the SylvianWssure, Wernicke’s area
(seeWgure 3.1), can produce a completely diVerent form of aphasia in
which the patient produces speech which isXuent and grammatical but
which fails to hit appropriate words, substituting instead inappropriate
words or meaningless syllables. From this it seems that in most subjects
Wernicke’s area plays a crucial role in lexical retrieval: crudely put, while
Broca’s area is handling the syntax, Wernicke’s area is doing the semantics.
However, lexical retrieval itself is not just a package deal which one
either has or completely loses, as if the dictionary were either at one’s
Wngertips or entirely lost. There are a variety of diVerent deWcits in lexical
retrieval such as the various forms of anomia (impairments in the use of
nouns). Patients have been found with speciWcdeWcits in the naming of
living things, or abstract things, or artefacts, or colours, or bodily parts, or
people, or fruits and vegetables – in fact, just about any category of items
one can think of. These strange problems of mental functioning are far
from being fully understood. But there does at least appear to be some
60 Modularity and nativism