From: pesetsk@athena.mit.edu (David M Pesetsky)
Subject: Re: Prototypes
Organization: Massachusetts Institute of Technology
Date: Wed, 26 Aug 1992 21:44:44 GMT

In article <1992Aug26.160927.12506@ils.nwu.edu> pautler@ils.nwu.edu (David Pautler) writes:
>In article <1992Aug26.120018.9260@athena.mit.edu>, pesetsk@athena.mit.edu (David M Pesetsky) writes:
>
>You appear to be claiming that the classical view of categories allows for
>the possibility that the necessary and sufficient conditions are inaccurate.
>English is a member of the Germanic language category by the end of your
>example, isn't it?  

I wasn't clear enough in what I wrote. Let me give a clearer example
that gets even farther from Esperanto.

As you may know, the various towns of the Boston area were never
incorporated into Boston the way the various towns of the New York area
were incorporated as boroughs of the City of New York.  Brookline, for
example, flows out of adjoining neighborhoods that belong to Boston, is
served by the same mediocre public transportation system, would have the
status of a neighborhood in New York -- yet is a separate town entirely,
as are Cambridge, Somerville, Belmont, Watertown, etc.  Now if someone
asks me "Is X (who is from Brookline) from Boston?", there is a clear
correct answer: no.

Nonetheless, in the right context, under the right conditions, a person
might very well say "yes", or list a Brookline restaurant when asked for
the name of a good restaurant in Boston.  And I could very well believe
that rigorous experimentation could pick up an extra millisecond or two
in a decision task that ended up with someone claiming that, yes some
Brookline restaurant or other is in Boston.  Now there need be no
prototype here for Boston.  You are either in it or you're not, and
Brookline is not in it, period.  There are no degrees of Bostonness, no
better or worse instances of Boston, simply an attempt on a hearer's
part to evaluate what is being asked and be helpful.

So what might be going on?  Context, presumably.  A person makes
assumptions about what is being asked that expand or limit the range of
correct answers.  Since these assumptions involve communication, and
guesses about other speakers, I can easily believe that data from such
guesses will be statistical in nature.  The person who asks about
Boston can be presumed, under the right circumstances, to really be
asking about "Boston Metropolitan area" or city within driving distance
of Boston, or something of the sort.

The ostrich case can very well be an inverse instance of the same thing.
Someone who talks about birds is more likely to be talking about birds
that have the properties that most (types of?) birds share, which
includes things like neck size or flying ability that don't necessarily
enter into anyone's mental definition of "bird".  When pressed, anyone
who knows what an ostrich is can easily place it in the bird category.
But in conversation or in particular tasks one might easily assume that
the speaker who talks about birds means some smaller set, just as one
might assume that something more than Boston is intended in the first
example.

Notice, by the way, that I am not demanding that anyone's definition
coincide with a textbook or dictionary definition, as in the
parallelogram case that someone else brought up.  Maybe someone really
defines parallelogram mentally so that a diamond orientation doesn't
count.  Maybe someone really thinks ketchup is a vegetable. I am simply
showing how a non-prototype definition, combined with pragmatic
influence on categorization, can yield results that one might view as
evidence for a prototype.  I have trotted this discussion out in various
places, always waiting to be set straight about the argument or
experiments that pry these things apart, but so far no one has
volunteered anything to me.  That's why I brought it up here.

By the way, I also see nothing wrong with a third view, by which a
person entertains several simultaneous definitions for "bird", and uses
context to determine which one is intended.  Perhaps the one that is fit
more often is more salient.  Voila, it takes longer to decide the Pope
is a bachelor, because he fits only a less salient definition.  We
clearly do this sort of thing all the time, for example whenever a
common-language term has a jargon-specific meaning, and prototypes get
you nowhere.  If you're doing botany, I guess, a tomato is a fruit.  I'd
say it's not a poor fruit, just a botanist's idea of a fruit.

-David Pesetsky
Xref: sparky sci.lang:6735 sci.cognitive:375