What is a deceptive cadence?

A deceptive cadence refers specifically to a harmonic progression that creates an expectation of resolution but instead resolves to a chord other than the tonic, often the submediant chord (the sixth scale degree). In this context, the dominant chord (the fifth scale degree) typically leads to what is anticipated to be the tonic chord, but instead, it resolves to a different harmony, creating a surprise or "deception." This technique is frequently used in music to maintain interest and prevent predictability in the harmonic structure.

In contrast, resolving back to the tonic represents a traditional cadence where the music feels complete, while a change in key signature refers to altering the tonal center, which is unrelated to this specific harmonic relationship. Additionally, while a cadence that slows down the tempo may affect the performance or interpretation of music, it does not define the structural quality of a deceptive cadence. This progression is a crucial part of tonal harmony and is often used by composers to enhance their work's emotional and dramatic qualities.