representation of input text in a conversation

[Christian J Lebiere]

If we take the theory seriously, John's solution (the sentence as
indexed list) and Niels' solution (the sentence as structured
interpretation) are not exclusive but complementary representations. 
Presumably, since words are heard one at a time, the interface (e.g.
ACT-R/PM) will record their occurrence in chunks like:

(utterance23
    isa sound
    type word
    time 123456
    content "how")

This is analogous to the list representation, and the time stamp can be
seen as a rough approximation of the indices (first, second, etc). 
However, since those words are heard with the goal of understanding the
sentence, a more abstract representation is also constructed as the
sentence is heard and becomes a declarative memory chunk when the goal
is popped:

(sentence5
    isa sentence
    type inquiry
    meaning proposition13)

or however the internal meaning of a sentence is represented.  This
sentence does not necessarily hold all (or even any of) the words, but
they can be retrieved independently (though not necessarily perfectly of
course) from their individual encoding.  Those representations are
variants of Wolfgang (b) and (a) solutions respectively, with some
differences (e.g. not necessarily all dimensions represented in (a) and
no pointer to the stimulus chunk in (b)).  Generally, this is a good
example of the origin and structure of chunks as discussed on pp. 23-24
of the ACT book (www.erlbaum.com).