[comp.ai] Assumptions in dialog

krulwich-bruce@CS.YALE.EDU (Bruce Krulwich) (05/26/88)

In article <180@proxftl.UUCP> tomh@proxftl.UUCP (Tom Holroyd) writes:
>True communication can only occur when both parties understand what all
>the symbols used to communicate mean.  This doesn't mean you have to
>explicitly define what you mean by "tree" every time you use the word
>tree, but it's a good idea to define it once, especially if it's something
>more complex than "tree" (with due respect to all sentient hardwood).

This can't be true.  True communications occurs whenever the two party's
understanding of the words used overlap in the areas in which they are in
fact being used.  Every word that a speaker uses will have a large set of
information associated with it in the speaker's mind, but only a small
subset of that information will actually be needed to understand what the
speaker is saying.  The trick is for the listener to (1) have the necessary
information as a subset of the information that he has about the word
(which is what you are considering above), and (2) correctly choose that
subset from the information he has (which is a form of the indexing problem).

>>The problem comes in deciding WHAT needs to be explicitly articulated
>>and what can be left in the "implicit background." That is a problem
>>which we, as humans, seem to deal with rather poorly, which is why
>>there is so much yeeling and hitting in the world.

Au contraire, humans do this quite well.  True, there are problems,
but most everyday communication is quite successful.  Computers at this
point can't succeed at this (the indexing problem) anywhere near as well
as people do (yet).

>Here's a simple rule: explicitly articulate everything, at least once.
>The problem, as I see it, is that there are a lot of people who, for
>one reason or another, keep some information secret (perhaps the
>information isn't known).

You are vastly underestimating the amount of knowledge you (and everybody)
have for every word, entity, and concept you know about.  More likely is
the idea that people have a pretty good idea of what other people know (see
Wilks' recent work, for example).  Again, this breaks down seemingly often,
but 99% of the time people seem to be correct.  Just because it doesn't
take any effort to understand simple sentences like "John hit Mary" doesn't
mean that there isn't alot of information selection and assumption making
going on. 


Bruce Krulwich