In linguistics

Linguistics

Linguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context....

, crossover effects are restrictions on possible binding

Binding (linguistics)

In linguistics, binding theory is any of a broad class of theories dealing with the distribution of pronominal and anaphoric elements. The idea that there should be a specialised, coherent theory dealing with this particular set of phenomena originated in work in transformational grammar in the 1970s...

 or coreference

Coreference

In linguistics, co-reference occurs when multiple expressions in a sentence or document refer to the same thing; or in linguistic jargon, they have the same "referent."...

 found between certain phrase

Phrase

In everyday speech, a phrase may refer to any group of words. In linguistics, a phrase is a group of words which form a constituent and so function as a single unit in the syntax of a sentence. A phrase is lower on the grammatical hierarchy than a clause....

s and pronoun

Pronoun

In linguistics and grammar, a pronoun is a pro-form that substitutes for a noun , such as, in English, the words it and he...

s. Crossover effects are divided into weak crossover or strong crossover.

Weak crossover

In syntax

Syntax

In linguistics, syntax is the study of the principles and rules for constructing phrases and sentences in natural languages....

, weak crossover (or WCO) refers to the restriction on possible binding or coreference found between certain phrases and pronouns, as the two below:

(1) ?Who_i does his_i mother love t_i?

(2) ?His_i mother loves [each boy]_i.

In (1), the object wh

Interrogative word

In linguistics, an interrogative word is a function word used for the item interrupted in an information statement. Interrogative words are sometimes called wh-words because most of English interrogative words start with wh-...

-phrase who is said to have 'crossed over' the pronoun 'his' embedded in the subject. The same set of data found with quantifiers

Quantification

Quantification has several distinct senses. In mathematics and empirical science, it is the act of counting and measuring that maps human sense observations and experiences into members of some set of numbers. Quantification in this sense is fundamental to the scientific method.In logic,...

 has often been claimed to be due to a covert movement of the quantifier phrase at a more abstract level of syntactic representation (such as Logical Form

Logical form (linguistics)

In the field of linguistics, particularly in the minimalist program, Logical Form , refers to a mental representation of a linguistic expression, derived solely from Surface Structure. In the words of Chomsky, LF captures "those aspects of semantic representation that are strictly determined by...

 (LF)).

Strong crossover

Strong crossover (SCO) refers to the restriction on possible binding or coreference found between certain phrases and pronouns, as below:

(3) *Who_i does he_i love t_i?

(4) *He_i loves each boy_i.

In (3), the object wh

Interrogative word

In linguistics, an interrogative word is a function word used for the item interrupted in an information statement. Interrogative words are sometimes called wh-words because most of English interrogative words start with wh-...

-phrase who is said to have "crossed over" the subject pronoun he; in this configuration, the individuals picked out by he cannot covary with those selected by who (that is, he cannot be bound by the quantifier associated with who). The same set of data found with quantifiers, as in (4), has often been claimed to be due to a covert movement of the quantifier phrase at a more abstract level of syntactic representation (such as Logical Form (LF)).

Crossover effects were originally discovered by Paul Postal

Paul Postal

Paul Martin Postal is an American linguist and member of the faculty of New York University.Postal received his PhD from Yale University in 1963 and taught at MIT until 1965. That year, he moved to the City University of New York...

 in 1971; the division into 'weak' and 'strong' is due to Tom Wasow

Tom Wasow

Thomas A. Wasow is an American linguist, the Clarence Irving Lewis Professor of Philosophy at Stanford University.Wasow did his undergraduate studies in mathematics at Reed College, graduating in 1967. He earned his Ph.D. in linguistics from the Massachusetts Institute of Technology in 1972, and...

, whose dissertation describes the fact that for many speakers, the restriction on binding is felt to be stronger in cases like (3) and (4) than in Weak Crossover configurations like (1) and (2).