11.4.9 Binding constraints

There are several constraints governing the resolution of pronouns to textual antecedents.

There are several constraints governing the resolution of pronouns to textual antecedents. The structure of discourse, a constraint which we implemented using the notion of accessibility, is just one of them. Let's have a look at the binding constraint, illustrated by the following sentences:

``* John_i loves him_i .''

``John_i loves himself_i .''

In the first example, the pronoun ``him'' cannot have ``John'' as antecedent. However, in the second example, the pronoun ``himself'' can only have ``John'' as antecedent. (``himself'', ``herself'', and so on, are called reflexive pronouns.)

Even though the intuitions beyond the binding constraint seem relatively easy to grasp, it is surprisingly hard to implement them. This is not only because there is an interplay between syntax and semantics, but also because there are subtle relaxations in the use of reflexive pronouns in other contexts (at least this holds for English). Consider for instance the following example, where both the use of a normal pronoun or a reflexive pronoun are felicitous:

``John_i drew a picture of him_i.''

``John_i drew a picture of himself_i.''

For these reasons, we will focus on ordinary pronouns in the scope of this chapter, and implement the binding constraint for pronouns in object position by checking the DRS for illegitimate DRS-conditions. Here the use of a simple heuristic will do: we won't allow basic DRS-conditions that have two identical arguments. This will prevent pronouns in object position of a transitive verb to refer to the subject noun phrase. The reader is asked to do the following exercise to get a full understanding of the implementation of this constraint in the DRS threading program.

Exercise 11.4

The binding constraint heuristic is implemented with the help of the predicate bindingDrs/1 in drt.pl. Check out the definition of this predicate, and find out when it is used. Think of cases where this heuristic might give the wrong predictions. Also think of ways to extend this heuristic to cover reflexive pronouns.

Aljoscha Burchardt, Stephan Walter, Alexander Koller, Michael Kohlhase, Patrick Blackburn and Johan Bos
Version 1.2.5 (20030212)