In linguistics, control is a construction where the understood subject of a given predicate is determined by some expression in context. Stereotypical instances of control involve verbs. A superordinate verb "controls" a subordinate, non-finite verb. Control was intensively studied in the Government and Binding (GB) framework in the 1980s, and much of the terminology from that era is still used today. In the days of Transformational Grammar, control phenomena were discussed in terms of Equi-NP deletion. Control is often analyzed in terms of a null pronoun called PRO. Control is also related to raising, although there are important differences between control and raising. Most if not all languages have control constructions and these constructions tend to occur frequently.
Standard instances of (obligatory) control are present in the following sentences:
- Susan promised us to help. - Subject control with the obligatory control predicate promise
- Fred stopped laughing. - Subject control with the obligatory control predicate stop
- We tried to leave. - Subject control with the obligatory control predicate try
- Sue asked Bill to stop. - Object control with the obligatory control predicate ask
- They told you to support the effort. - Object control with the obligatory control predicate tell
- Someone forced him to do it. - Object control with the obligatory control predicate force
Each of these sentences contains two verbal predicates. Each time the control verb is on the left and the controlled verb on the right. The control verb determines which expression is interpreted as the "subject" of the verb on the right. The first three sentences are examples of subject control, because the subject of the control verb is also the understood subject of the controlled verb. The second three sentences are instances of object control, because the object of the control verb is also the understood subject of the controlled verb. The argument of the matrix predicate that functions as the "subject" of the embedded predicate is the controller. The controllers are in bold in the examples.
Control verbs vs. auxiliary verbs
Control predicates have semantic content; they semantically select their arguments, that is, their appearance strongly influences the nature of the arguments they take. In this regard, they are much different from auxiliary verbs, which lack semantic content and do not semantically select arguments. Compare the following pairs of sentences:
- a. Sam will go. - will is an auxiliary verb.
- b. Sam yearns to go. - yearns is a subject control verb.
- a. Jim has to do it. - has to is a modal auxiliary verb.
- b. Jim refuses to do it. - refuses is a subject control verb.
- a. Jill would lie and cheat. - would is a modal auxiliary.
- b. Jill attempted to lie and cheat. - attempted is a subject control verb.
The a-sentences contain auxiliary verbs that do not select the subject argument. What this means is that the embedded verbs go, do, and lie and cheat are responsible for semantically selecting the subject argument. The point is that while control verbs may have the same outward appearance as auxiliary verbs, the two verb types are quite different.
Non-obligatory or optional control
Control predicates (such as promise, stop, try, ask, tell, force, yearn, refuse, attempt) obligatorily induce a control construction. That is, when control predicates appear, they inherently determine which of their arguments controls the embedded predicate. Control is hence obligatorily present with these predicates. In contrast, many predicates can be controlled even when a superordinate control predicate is absent, e.g.
- He left singing all the way. - Non-obligatory control of the present participle singing
- Understanding nothing, the class protested. - Non-obligatory control of the present participle understanding
- Holding his breath too long, Fred passed out. - Non-obligatory control of the present participle holding
In one sense, control is obligatory in these sentences because the present participles singing, understanding, and holding are clearly controlled by the matrix subjects. In another sense, however, control is non-obligatory (or optional) because there is no control predicate present that necessitates that control occur. General contextual factors are determining which expression is understood as the controller. The controller is the subject in these sentences because the subject establishes point of view.
Arbitrary control occurs when the controller is understood to be anybody in general, e.g.
- Reading the Dead Sea Scrolls is fun. - Arbitrary control of the gerund reading.
- Seeing is believing. - Arbitrary control of the gerunds seeing and believing
- Having to do something repeatedly is boring. - Arbitrary control of the gerund having
The understood subject of the gerunds in these sentence is non-discriminate; any generic person will do. In such cases, control is said to be "arbitrary". Any time the understood subject of a given predicate is not present in the linguistic or situational context, a generic subject (e.g. 'one') is understood.
Theoretical linguistics posits the existence of the null pronoun PRO as the theoretical basis for the analysis of control structures. The null pronoun PRO is an element that impacts a sentence in a similar manner to how a normal pronoun impacts a sentence, but the null pronoun is unaudible. The null PRO is added to the controlled predicate, where it occupies the position that one would typically associate with an overt subject (if one were present). The following trees illustrate PRO in both constituency-based structures of phrase structure grammars and dependency-based structures of dependency grammars:
The constituency-based trees are the a-trees on the left, and the dependency-based trees the b-trees on the right. Certainly aspects of these trees - especially of the constituency trees - can be disputed. In the current context, the trees are intended merely to suggest by way of illustration how control and PRO are conceived of. The indices are a common means of identifying the controller of PRO and the controlled predicate, and the orange arrows indicate further the control relation. In a sense, the controller assigns its index to PRO, which identifies the argument that is understood as the subject of the controlled predicate.
The details of this tree are, again, not so important. What is important is that by positing the existence of the null subject PRO, the theoretical analysis of control constructions gains a useful tool that can help uncover important traits of control constructions.
Control vs. raising
Control must be distinguished from raising, though the two can be outwardly similar. Control predicates semantically select their arguments, as stated above. Raising predicates, in contrast, do not semantically select (at least) one of their dependents. The contrast is evident with the so-called raising-to-object verbs (=ECM-verbs) such as believe, expect, want, and prove. Compare the following a- and b-sentences:
- a. Fred asked you to read it. - asked is an object control verb.
- b. Fred expects you to read it. - expects is a raising-to-object verb.
- a. Jim forced her to say it. - forced is an object control verb.
- b. Jim believed her to have said it. - believes is a raising-to-object verb.
The control predicates ask and force semantically select their object arguments, whereas the raising-to-object verbs do not. Instead, the object of the raising verb appears to have "risen" from the subject position of the embedded predicate, in this case from the embedded predicates to read and to have said. In other words, the embedded predicate is semantically selecting the argument of the matrix predicate. What this means is that while a raising-to-object verb takes an object dependent, that dependent is not a semantic argument of that raising verb. The distinction becomes apparent when one considers that a control predicate like ask requires its object to be an animate entity, whereas a raising-to-object predicate like expects places no semantic limitations on its object dependent.
The different predicate types can be identified using expletive there. Expletive there can appear as the "object" of a raising-to-object predicate, but not of a control verb, e.g.
- a. *Fred asked there to be a party. - Expletive there cannot appear as the object of a control predicate.
- b. Fred expects there to be a party. - Expletive there can appear as the object of a raising-to-object predicate.
- a. *Jim forced there to be a party. - Expletive there cannot appear as the object of a control predicate.
- b. Jim believes there to have been a party. - Expletive there can appear as the object of a raising-to-object predicate.
The control predicates cannot take expletive there because there does not fulfill the semantic requirements of the control predicates. Since the raising-to-object predicates do not select their objects, they can easily take expletive there.
- See for instance van Riemsdijk and Williams (1986:128ff.), Cowper (1992:161ff.), Borsley (1996:126-144).
- Concerning the designation Equi-NP deletion for control structures, see for instance Bach (1974:116f.), Emonds (1976:193f. note 15), Culicover (1982:250).
- Accounts of control emphasize that control predicates semantically select their dependents, as opposed to raising predicates, which do not select one of their dependents. See for instance van Riemsdijk and Williams (1986:130), Borsley (1996:133), Culicover (1997:102).
- See van Riemsdijk and Williams (1986:137) and Haegeman (1994:277) concerning non-obligatory/optional control.
- Arbitrary control is discussed for instance by van Riemsdijk and Williams (1986:137f.), Cowper 1992:162), Culicover (1997:75-76), Carnie (207:285ff.).
- For accounts of PRO, see for instance van Riemsdijk and Williams (1986:132ff.), Cowper (1992:157ff.), Haegeman (1994:257ff.), Culicover (1997:75-77), Carnie (2007:395ff.).
- The constituency trees shown here are similar to those that were widely produced in the 1970s, e.g. Bach (1974). The dependency trees here are similar to those that are produced by Osborne and Groß (2012).
- Numerous GB trees like the one here can be found in, for instance, Haegeman (1994).
- Concerning the difference between control and raising, see Bach (1974:149), Culicover (1997:102), Carnie (2007:403ff.).
- The expletive is widely employed to distinguish control from raising constructions. See for instance Grinder and Elgin (1973:142-143), Bach (1973:151), McCawley (1988:121), Borsley (1996:127), Culicover (1997:102), Saito (1999:8-9).
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