Why Does the Leading Note Pull Towards the Tonic?

In C major, stop on B without playing C and the phrase often sounds unfinished. B is scale degree seven, only a semitone below the upper tonic, and is therefore called the leading note. Nearness alone, however, does not explain its full sense of direction. The stronger pull comes from tonal context: once the preceding harmony, bass and phrase have established C as the centre, B—especially within the dominant chord G–B–D—moves to C in a way that completes both melodic and harmonic motion.

This also explains why scale degree seven in natural minor often lacks the same urgent upward tendency, while harmonic minor commonly raises it by a semitone to create a leading note. The tonic does not physically “attract” the note. The expectation is structural, formed through recurring practices in Western tonal music. A composer may fulfil it, delay it, redirect it or deliberately deny it; a deceptive cadence works because the listener has already heard the expectation.

At the piano, it is easy to treat the leading note as merely the next key to press. What matters more is hearing where it points. If B is over-accented, C can sound struck rather than reached; if B has no direction, C becomes only the next pitch in sequence. Good touch need not exaggerate the effect. It should preserve a sense of incompletion on B so that C arrives as structural resolution, not simply as a semitone higher.

https://musictheory.pugetsound.edu/mt21c/ScaleDegreeNames.html
https://musictheory.pugetsound.edu/mt21c/HarmonicFunction.html