The Science of Music and Memory
How Rhyme, Rhythm, and Melody Help You Memorize — Meet Chunking
'583-927-416' and '583927416' contain the same nine digits. The first can be handled as three chunks, reducing the number of units held at once. Songs may offer similar boundaries and retrieval cues.
Your mental workbench is surprisingly small
Under many conditions, about four meaningful units is a useful estimate for what working memory can hold at once. Treating '583927416' as nine separate digits is demanding; reading '583-927-416' as three three-digit chunks may reduce the number of units in use.
Grouping information into meaningful units is called chunking. A song does not guarantee that this happens automatically, but phrase boundaries and repetition can provide a structure for building chunks.
Songs pre-slice information for you
Lyrics have phrase boundaries and repeated sections such as choruses. Aligning material with those boundaries can make it easier to handle phrase by phrase, though a poor fit between the tune and the material can also add difficulty.
Rhyme and rhythm may also cue the next phrase. That does not mean a song guarantees recall. For order-sensitive material, check whether you can reproduce the sequence accurately without the music as well.
If a skeleton can be borrowed, borrow it
Building a memory framework from scratch is hard. Borrow the skeleton of a melody you already know, and chunking, rhyme, and meter come included. Setting facts to a familiar tune has never gone out of style because it is simply rational.
The trick is to place what you want to remember at the phrase boundaries. Stuff too much into one phrase and the chunks grow too large to help. For exam prep, the highest-value use is the handful of stubborn items that refuse to stick any other way.