Questions: Harmonic Function: Tonic, Subdominant, and Dominant

Question 1

In a deceptive cadence (V–vi), the vi chord works as a surprise because it temporarily substitutes for which function?

• A. Dominant function — vi shares notes with V and can extend the tension
• B. Subdominant function — vi creates motion away from tonic just as IV does
• C. Tonic function — vi shares enough pitches with I to feel like a weakened form of rest
• D. No function — deceptive cadences break the functional system entirely

Answer: (C)

The deceptive cadence works precisely because vi can stand in for I (tonic function). In C major, the I chord contains C–E–G; the vi chord contains A–C–E — two of the three notes are shared. The listener expects I (tonic resolution) after V, and gets vi instead — a chord that still provides some sense of rest because of those shared tones, but not full resolution. Calling vi 'dominant' or 'subdominant' would mischaracterize what it does in this context.

Question 2

Why does the V chord create stronger pull toward resolution than the IV chord does?

• A. The V chord is louder by convention in tonal music
• B. The V chord contains the leading tone — the seventh scale degree, a semitone below tonic — which creates upward pressure toward resolution
• C. The V chord has more notes in common with I than IV does
• D. The V chord is always played as a dominant seventh, adding dissonance that demands resolution

Answer: (B)

The leading tone (scale degree 7, one semitone below tonic) is the acoustic engine of dominant function. Its half-step proximity to the tonic creates a strong gravitational pull upward. The V chord contains scale degrees 5, 7, and 2; the 7 is the leading tone. The IV chord (scale degrees 4, 6, 1) does not contain the leading tone, which is why it creates directed departure rather than urgent tension. Option D is partially true (V7 is common) but misses the root cause — even a plain V triad exerts dominant pull because of the leading tone.

Question 3

The subdominant chord (IV) creates strong harmonic tension that demands immediate resolution, similar to the dominant chord.

• T. True
• F. False

Answer: False

Subdominant function creates departure and directed motion — a sense of leaving home — but not the urgent tension of dominant function. IV sounds stable enough to linger on; V feels unstable and pushes for resolution. This distinction is why the classic progression I–IV–V–I works: IV takes us away from tonic gently, V creates the tension that makes the final I feel satisfying. Confusing subdominant with dominant undermines the whole three-function model.

Question 4

The ii chord can serve subdominant function in a ii–V–I progression because it shares most of its pitches with the IV chord.

• T. True
• F. False

Answer: True

In C major: IV = F–A–C; ii = D–F–A. Three of the four notes in a ii7 chord (D–F–A–C) match notes in IV or IV7 (F–A–C–E). This overlap gives ii a similar acoustic weight and directional character to IV — both create a sense of moving away from tonic toward the dominant. The ii–V–I progression is ubiquitous in jazz precisely because ii is a smooth functional substitute for IV, leading into V with particular momentum.

Question 5

Why is asking 'what is this chord doing?' a more powerful analytical question than 'what Roman numeral is this?'

Model answer: Roman numerals identify chords by their scale position, but the same chord can serve different functions depending on context. A vi chord usually provides tonic-substitute function, but the same pitches in a different harmonic context could behave differently. Functional thinking reveals the underlying drama of tonal music — departure from home (subdominant), accumulation of tension (dominant), return to rest (tonic) — which is the real engine of progression. It also explains exceptions: why a deceptive cadence works, why ii substitutes for IV, why diminished chords are so restless.

Functional analysis unlocks harmonic substitution, explains cadence types, and reveals the emotional logic behind progressions. A student who only knows Roman numerals can label chords; a student who understands function can explain why progressions move the way they do and compose convincing music. The three functions (tonic, subdominant, dominant) act as a grammar for tonal music — knowing the grammar lets you understand and generate sentences, not just label individual words.