In English, 'Does he leave?' is grammatical but '*Leaves he?' is not—even though both reorder subject and verb. Under the Head Movement Constraint, the BEST explanation is:
A'Leaves' is semantically too heavy for movement; auxiliaries are lightweight and therefore movable
B'Does' is in T (Tense head) and moves to C (Complementizer head)—one step up the tree; 'leaves' is in V and would need to skip T entirely to reach C, violating the locality requirement
CEnglish prohibits main verb movement for purely historical reasons unrelated to syntactic structure
D'Does' moves because it lacks semantic content; movement is blocked for content words with full lexical meaning
The HMC requires that a head can only move to the head of its *immediately dominating* phrase—one step at a time. 'Does' sits in T; CP immediately dominates TP, so T's head can move to C—one local step. 'Leaves' sits in V; VP is dominated by TP, which is in turn dominated by CP. To reach C, 'leaves' would need to skip TP entirely, violating the HMC. The constraint is about locality in the syntactic tree, not about semantic weight or lexical content.
Question 2 Multiple Choice
A head X must reach head position Y, which is three levels above it in the syntactic tree. According to the Head Movement Constraint, the movement must proceed:
AX cannot move at all; any movement spanning more than one level is categorically blocked
BX can move directly to Y if Y is a functional head rather than a lexical head
CX must move through each intermediate head position in a series of local steps, landing at each intermediate head before continuing upward
DX can move to Y in one step only if there are no phonologically overt heads occupying the intermediate positions
The HMC permits long-distance head movement through successive local steps—each individual movement must be from a head to the immediately dominating head. This is analogous to a series of one-step moves rather than a single long jump. French main verb movement to positions above adverbs (demonstrating V-to-T movement) is permitted because each step is local: V moves to T, and T can then move to C. What is blocked is skipping a level—not moving through multiple levels via successive local steps.
Question 3 True / False
In French, finite main verbs appear to move to positions higher in the syntactic tree than they do in English, yet this is fully consistent with the Head Movement Constraint.
TTrue
FFalse
Answer: True
True. The HMC requires that each *individual step* of head movement be local—a head can only land in the immediately dominating head position. French main verbs move from V to T overtly (as shown by their position relative to adverbs and negation), and from T they can proceed to C if needed. Each step is local, so the HMC is satisfied. The cross-linguistic variation is not about whether the HMC applies, but about whether V-to-T movement is overt (French) or covert/absent (English).
Question 4 True / False
The Head Movement Constraint allows a head to move freely to any higher head position in the tree, provided it lands in a head position rather than a specifier or adjunct position.
TTrue
FFalse
Answer: False
False. The HMC requires not just that a head land in a head position, but specifically in the head of the *immediately dominating* phrase. A head cannot skip levels even if its destination is a head position rather than a specifier or adjunct. It is the locality of the landing site—not just its categorical type—that the HMC restricts. This is the crucial point: movement must be local at every step.
Question 5 Short Answer
Why is the Head Movement Constraint considered evidence that syntactic locality is a fundamental design feature of language, rather than an arbitrary restriction on movement?
Think about your answer, then reveal below.
Model answer: The HMC shows that syntactic operations respect structural boundaries at every level—they cannot 'see past' intermediate positions to reach a distant target. This locality isn't arbitrary because it generalizes: the same constraint on ignoring intervening structure appears in wh-movement (islands), raising, and other displacement phenomena. Heads must move through intermediate positions rather than skipping them, which reveals that syntax processes structure incrementally and cannot access non-adjacent positions directly. This makes locality a general architectural principle of the grammar, not a stipulation about verbs or auxiliaries specifically.
The power of the HMC as evidence is that it explains a cross-linguistic pattern (auxiliary movement vs. full-verb movement, verb positioning relative to adverbs) without stipulating language-specific rules. The explanation falls out from a general locality principle. When a theoretical principle predicts observed variation across many languages and constructions without being stipulated for each separately, it is evidence that the principle reflects something fundamental about the grammatical system.