Models of Comprehension 587to capture the core idea—how people understand a sentence
when they are not analyzing it in all its detail. This sort of
representation is useful mainly because it allows the psychol-
ogist to count so-called idea units in the comprehension as
well as reproduction of a text. Counting words is not very
useful with texts. In a list of random words, whether a subject
recalls 12 or 15 words is a meaningful statistic. The exact
number of words someone recalls from a text, on the other
hand, is not necessarily directly related to either comprehen-
sion or memory; for most purposes, the number of ideas
matters, rather than the words expressing them. Thus, the
propositional representation of the sentence John read the old
book in the libraryis
Predicate: READ
Agent: JOHN
Object: BOOK
Modifier: OLD
Location: LIBRARYParaphrasing this sentence as The book, which was old, was
read by John in the librarydoes not change this propositional
representation. For purposes of scoring a recall protocol, one
can count either sentence as one complex proposition, or as
one core proposition, one modifier, and one location, depend-
ing on the grain of the analysis that is desired.
The W. Kintsch and van Dijk model assumes that under-
standing a text means constructing a propositional represen-
tation of the text. This representation consists of a network
of propositions. Propositions that share a common argument
are linked (in the example above, the proposition would be
linked to other propositions containing one or more of the
arguments John, book, orlibrary). However, propositions
can be linked only if they reside in the reader’s working
memory at the same time. The capacity of this working
memory is limited (estimates usually range between three to
five propositions). A spreading activation process among the
propositions in working memory determines their activation
level. As the next sentence in a text is read, working memory
is cleared: The propositions from the previous processing
cycle are added to long-term memory and the propositions
from the current sentence(s) are added to working memory.
However, to ensure continuity, the most activated proposi-
tion(s) from the last cycle is retained in a short-term buffer,
so that it can be linked with the propositions of the current
sentence. In this way, a connected textbase is gradually
constructed as the text is processed sentence by sentence.
This textbase is called the microstructureof the text. It repre-
sents the meaning of all the sentences of a text in terms of a
propositional network, as an ideal reader would construct it.
The links in this structure are determined jointly by the nature
of the text and by the capacity limits of working memory and
the short-term buffer. Furthermore, those propositions that
are most strongly interlinked in this network will gain the
greatest memory strength in the spreading activation process.
In addition, the W. Kintsch and van Dijk model also con-
structs a macrostructurerepresentation of a text. Schemas
play a role at this level: They allow the reader to identify the
structurally most important propositions in a text and their
interrelationships, thus providing a basis for the formation of
a macrostructure. Intuitively, the macrostructure represents
the gist of a text, whereas the microstructure represents all of
its detailed content.
In a large number of studies, the W. Kintsch and van Dijk
model has been shown to predict the data from psychological
experiments with texts quite well—comprehension as well as
memory (e.g., Graesser, Millis, & Zwaan, 1997; W. Kintsch,
1974; W. Kintsch & van Dijk, 1978; van Dijk & Kintsch,
1983). The model thus justified the basic premise of the psy-
chological processing approach to text comprehension: that
cognitive constraints as well as linguistic constraints must be
taken into account in modeling text comprehension.The Construction-Integration ModelThe mental representation that results from reading a text is,
however, only in part determined by the content and structure
of the text itself—the process that the van Dijk and Kintsch
(1983) model attempts to describe. The reader’s goals and
prior knowledge are equally important factors. Schema the-
ory provided the first account of how prior knowledge influ-
ences comprehension. An alternative account, which leaves
room for the top-down effects of schemas but relies more
heavily on bottom-up processes, has been developed by
W. Kintsch (1988, 1998) within the general framework of the
van Dijk and Kintsch processing model.
Consider what happens when a reader encounters a
homonym in a discourse context. Almost always, only the
context-appropriate meaning of the word comes to mind.
However, experimental studies, using both lexical decision
and eye movement methods, suggest for a very brief period
of time, about 350 ms, both meanings of a homonym are ac-
tivated under certain conditions (Rayner, Pacht, & Duffy,
1994; Swinney, 1979; also see the chapter in this volume by
Rayner, Pollatsek, Starr, & Wurm). This observation suggests
that it is not a top-down process, such as a schema, that
primes the context-appropriate meaning or filters out the in-
appropriate ones, but that all meanings are activated and that
the context then suppresses the activation of inappropriate
meanings. The construction-integration model is based on
this idea. It assumes that construction processes during