You can’t do any real acting until you memorize your lines.

You can lay a great foundation for real acting while you’re still on book.  You can experiment with options while you’re still on book.  You can explore your character plenty.  You can pay attention to what your fellow actors are doing and try to receive it and see how what they are doing may impact your own choices.

The one thing you can’t do until you’re off book is act.

Why?  Because your subconscious is what does the acting, and it can’t function when your left brain is working on remembering lines.  When your left brain is that kind of active, you subconscious just can’t be heard.

Here are the five stages of memorizing your lines:

1. You start to know bits and pieces of the scene.  But you’ve still got big gaps of lines you can’t remember.
2. You kind of know the whole scene, but it’s work to remember it.  We can see the wheels turning every time it’s your turn to speak.
3. The wheels are no longer obvious, but you’ve got certain lines you’ve got a mental block on, and when you hit them, the wheels go into overdrive.
4. The mental blocks have disappeared.  Technically, you’ve got the scene completely memorized.  But in truth, one-quarter to one-half of your attention is focused on the lines and whether or not you remember the next one.  You remember every single one; it’s just that you are conscious of the fact that you are remembering them.   Conscious isn’t good in acting.
5. You can recite your lines without pausing.  They have become second nature, and fall out of your mouth with you having to think about them.

The gap between stages 4 and 5 is probably at least one week.  I memorize lines easily and quickly, but I can tell the difference between when I am first officially “off book” and how I can work a week later.  (So can the audience.)  Assume that you’ll have at least one week of “acclimation”.

This period of “acclimation” and the fact that you can’t do any quality acting until you are off book are my two biggest arguments for beginning to memorize your lines the day you get your script.  Before your first rehearsal, before you’ve finished blocking.  The earlier you have your lines memorized, the better your performance will be.  Guaranteed.

See Part II here.  See Word Choice, Memorization, and Script Analysis Part I here.  See Word Choice, Memorization and Script Analysis Part II here.