Should you memorize your presentation? There are two correct answers to this question:
1. No, you shouldn’t memorize your talk, but you should be familiar with the flow and have practiced enough that it sounds natural.
2. Yes, you should memorize your talk so well that it sounds natural, not robotic.

Personally, I don’t memorize wording. But I know memorizing makes certain people feel more relaxed and secure. The important thing is that you practice enough so that your talk sounds natural.

If you don’t memorize and don’t practice, your talk will be littered with “uhs” and “umms” while you try to work out what to say next. That sucks.

If you memorize, but not well enough, you’ll fall into the uncanny valley. From the TED Talks book: “[The Uncanny Valley] is a term borrowed from a phenomenon in computer animation where the technology of animating humanlike characters is super-close to seeming real but is not quite there. The effect is creepy: worse than if the animator had steered clear of realism altogether.” Speakers that try to memorize, but don’t do it well enough, fall here. Their talk will sound robotic and rehearsed. But by persisting with practice, you can fight through the uncanny valley. You need to know the talk so well that recalling it is a snap, no matter where you are interrupted. “Then you can use your conscious attention to focus on the meaning of the words once again.”

(image via Slate)

So what is the conclusion? Practice. Then practice again. By practicing and preparing, you can give a talk that values the audience’s time and wins you support.