Anaphora (linguistics)

In linguistics, anaphora () is the use of an expression whose interpretation depends upon another expression in context (its antecedent or postcedent). In a narrower sense, anaphora is the use of an expression that depends specifically upon an antecedent expression and thus is contrasted with cataphora, which is the use of an expression that depends upon a postcedent expression. The anaphoric (referring) term is called an anaphor. For example, in the sentence "Sally arrived, but nobody saw her", the pronoun "her" is an anaphor, referring back to the antecedent "Sally". In the sentence "Before her arrival, nobody saw Sally", the pronoun "her" refers forward to the postcedent "Sally", so "her" is now a "cataphor" (and an anaphor in the broader, but not the narrower, sense). Usually, an anaphoric expression is a proform or some other kind of deictic (contextually-dependent) expression. Both anaphora and cataphora are species of endophora, referring to something mentioned elsewhere in a dialog or text.
Anaphora is an important concept for different reasons and on different levels: first, anaphora indicates how discourse is constructed and maintained; second, anaphora binds different syntactical elements together at the level of the sentence; third, anaphora presents a challenge to natural language processing in computational linguistics, since the identification of the reference can be difficult; and fourth, anaphora partially reveals how language is understood and processed, which is relevant to fields of linguistics interested in cognitive psychology.
Nomenclature and examples.
The term "anaphora" is actually used in two ways.
In a broad sense, it denotes the act of referring. Any time a given expression (e.g. a proform) refers to another contextual entity, anaphora is present.
In a second, narrower sense, the term "anaphora" denotes the act of referring backwards in a dialog or text, such as referring to the left when an anaphor points to its left toward its antecedent in languages that are written from left to right. Etymologically, "anaphora" derives from Ancient Greek ἀναφορά (anaphorá, "a carrying back"), from ἀνά (aná, "up") + φέρω (phérō, "I carry"). In this narrow sense, anaphora stands in contrast to cataphora, which sees the act of referring forward in a dialog or text, or pointing to the right in languages that are written from left to right: Ancient Greek καταφορά (kataphorá, "a downward motion"), from κατά (katá, "downwards") + φέρω (phérō, "I carry"). A proform is a cataphor when it points to its right toward its postcedent. Both effects together are called either anaphora (broad sense) or less ambiguously, along with self-reference they comprise the category of endophora.
Examples of anaphora (in the narrow sense) and cataphora are given next. Anaphors and cataphors appear in bold, and their antecedents and postcedents are underlined:
A further distinction is drawn between endophoric and exophoric reference. Exophoric reference occurs when an expression, an exophor, refers to something that is not directly present in the linguistic context, but is rather present in the situational context. Deictic proforms are stereotypical exophors, e.g.
Exophors cannot be anaphors as they do not substantially refer within the dialog or text, though there is a question of what portions of a conversation or document are accessed by a listener or reader with regard to whether all references to which a term points within that language stream are noticed (i.e., if you hear only a fragment of what someone says using the pronoun "her", you might never discover who "she" is, though if you heard the rest of what the speaker was saying on the same occasion, you might discover who "she" is, either by anaphoric revelation or by exophoric implication because you realize who "she" must be according to what else is said about "her" even if "her" identity is not explicitly mentioned, as in the case of homophoric reference).
A listener might, for example, realize through listening to other clauses and sentences that "she" is "a Queen" because of some of her attributes or actions mentioned. But which queen? Homophoric reference occurs when a generic phrase obtains a specific meaning through knowledge of its context. For example, the referent of the phrase "the Queen" (using an emphatic definite article, not the less specific "a Queen", but also not the more specific "Queen Elizabeth") must be determined by the context of the utterance, which would identify the identity of the queen in question. Until further revealed by additional contextual words, gestures, images or other media, a listener would not even know what monarchy or historical period is being discussed, and even after hearing "her" name is "Elizabeth" does not know, even if an English-UK Queen Elizabeth becomes indicated, if this queen means "Queen Elizabeth I" or "Queen Elizabeth II" and must await further clues in additional communications. Similarly, in discussing 'The Mayor' (of a city), the Mayor's identity must be understood broadly through the context which the speech references as general 'object' of understanding; is a particular human person meant, a current or future or past office-holder, the office in a strict legal sense, or the office in a general sense which includes activities a mayor might conduct, might even be expected to conduct, while they may not be explicitly defined for this office.
In generative grammar.
The term "anaphor" is used in a special way in the generative grammar tradition. Here it denotes what would normally be called a reflexive or reciprocal pronoun, such as "himself" or "each other" in English, and analogous forms in other languages. The use of the term "anaphor" in this narrow sense is unique to generative grammar, and in particular, to the traditional binding theory. This theory investigates the syntactic relationship that can or must hold between a given proform and its antecedent (or postcedent). In this respect, anaphors (reflexive and reciprocal pronouns) behave very differently from, for instance, personal pronouns.
Complement anaphora.
In some cases, anaphora may refer not to its usual antecedent, but to its complement set. In the following example a, the anaphoric pronoun "they" refers to the children who are eating the ice-cream. Contrastingly, example b has "they" seeming to refer to the children who are not eating ice-cream:
In its narrower definition, an anaphoric pronoun must refer to some noun (phrase) that has already been introduced into the discourse. In complement anaphora cases, however, the anaphor refers to something that is not yet present in the discourse, since the pronoun's referent has not been formerly introduced, including the case of 'everything but' what has been introduced. The set of ice-cream-eating-children in example b is introduced into the discourse, but then the pronoun "they" refers to the set of non-ice-cream-eating-children, a set which has not been explicitly mentioned.
Both semantic and pragmatics considerations attend this phenomenon, which following discourse representation theory since the early 1980s, such as work by Kamp (1981) and Heim (File Change Semantics, 1982), and generalized quantifier theory, such as work by Barwise and Cooper (1981), was studied in a series of psycholinguistic experiments in the early 1990s by Moxey and Sanford (1993) and Sanford et al. (1994). In complement anaphora as in the case of the pronoun in example b, this anaphora refers to some sort of complement set (i.e. only to the set of non-ice-cream-eating-children) or to the maximal set (i.e. to all the children, both ice-cream-eating-children and non-ice-cream-eating-children) or some hybrid or variant set, including potentially one of those noted to the right of example b. The various possible referents in complement anaphora are discussed by Corblin (1996), Kibble (1997), and Nouwen (2003). Resolving complement anaphora is of interest in shedding light on brain access to information, calculation, mental modeling, communication.
Anaphora resolution – centering theory.
There are many theories that attempt to prove how anaphors are related and trace back to their antecedents, with centering theory (Grosz, Joshi, and Weinstein 1983) being one of them. Taking the computational theory of mind view of language, centering theory gives a computational analysis of underlying antecedents. In their original theory, Grosz, Joshi, & Weinstein (1983) propose that some discourse entities in utterances are more "central" than others, and this degree of centrality imposes constraints on what can be the antecedent. 
In the theory, there are different types of centers: forward facing, backwards facing, and preferred. 
Forward facing centers.
A ranked list of discourse entities in an utterance. The ranking is debated, some focusing on theta relations (Yıldırım et al. 2004) and some providing definitive lists.
Backwards facing center.
The highest ranked discourse entity in the previous utterance.
Preferred center.
The highest ranked discourse entity in the previous utterance realised in the current utterance.