The notion of bounding was first observed in the early generative grammar by, for instance, John R. Ross (1967). He noticed that movement is impossible out of certain phrases called Extraction islands. This evidence was further interpreted in terms of the Government and Binding Theory and Subjacency condition in the following way:
(1) whoi did [AGRP Bill think [CP ti [AGRP John saw ti ]]]
(2) *whoi did [AGRP John ask [CP whenj [AGRP ti fixed the car tj ]]]
(3) *whoi did [AGRP John believe [DP the statement [CP ti that [AGRP Bill hit ti ]]]]2
In (1) the wh-element moves out of the object position of the embedded clause via cyclic movement, crossing only one AgrP at a time. Thereby, it respects the Subjacency condition and the sentence is grammatical. The details of this movement are presented in the diagram below:
(1)
As the specifier of CP position is empty in (1), the wh-element may use it as an escape hatch before moving further. In the example (2), on the other hand, the specifier of CP position is already taken and the wh-element moves over two AgrP at a time, violating the Subjacency condition and yielding the ungrammatical sentence.
(Chomsky 1977: 73) ↩
For more examples see Cook and Newson (2007). ↩