I successfully completed my month-long project of memorizing a poem or a poetic speech each day in April, National Poetry Month. As it was also Shakespeare's birthday month, much of what I memorized consisted of his sonnets and a few speeches. As my system was to memorize until I could perform the poem verbatim by looking directly into the my video camera, there was not enough time to get the text from working memory to long term memory. Consequently, effortless verbatim memory of the poems faded almost as soon as I put the poems aside. This made me question the value of this practice. It differs from when I am memorizing lines for a theatrical performance, either ensemble or solo. There the script is repeated daily over a period of days or, generally, weeks and then performed usually several times before a live audience. Even so, after a period of weeks, perhaps even days, large chunks or possibly most of the script fades from instant and effortless retrieval. This makes me think that the concept of short term or "working" memory is relative and that deeper "grooves" need to be "ploughed" if the material needs to live in the memory longer, such as for the run of a show. The moment other material holds one's attention in place of the memorized text, that is, once the memorized text is not continually refreshed by either rehearsal or performance, it will begin to fade.
This is not the case with material that has entered long term memory, it seems. I, along with many actors, still have large chunks of Shakespeare still pretty much word perfect in my memory despite years - more than a decade - of rehearsal or performance. How long and what process is required to transfer a text from working to long term memory I am still uncertain. Usually, I claim it a matter of being able to perform the piece "in your sleep," or otherwise without having to think about it; automatically.
I have been contemplating the classical techniques in light of my own experience and experiments. I think the places and images technique adaptable IF done with an awareness of the structures of poetry. Whereas the ancients memorized a speech by taking an imaginary walk through a building they had memorized and then mentally superimposed images on individual architectural units, I think it effective to memorize the structure of the poem and superimpose or slot words and images onto and into that structure. For example, the English sonnet consists of fourteen lines of iambic pentameter - ten (occasionally eleven) syllables and five primary stresses. The rhyme scheme for the Shakespearean sonnet is ababcdcdefefgg, while others use some variations on that. It helps me to take a mental walk across the lines of of the sonnet, line by line from left to right and down to the next line, until I perform the sonnet verbatim. Meantime, I am also seeing a sequence of images, like a mini-film, as I plough through the lines.
Performing the words aloud also helps by adding the muscle memory of articulation and pronunciation to the memory support system. Speaking the words aloud as I copy them by hand onto paper also help dig some grooves. After having memorized the poem, writing it by hand onto paper without referring to the original is a good test of accuracy.
Working on the text just before going to sleep and then immediately upon awakening also seems to help the process.
After putting as many useful schemes of memorization to work, the ultimate test of really "owning" the text is to be able to perform it with no hesitation (except deliberate ones for meaning and emotion) as if one is making up the words spontaneously.