The most likely effect of too much type on one slide during a presentation is the following: Answer A. The audience will stop listening to the presenter in order to read the slide. It's commonly know that the 70 % of the people in the world are visual learners. The auditory ability in them is about the 20 % to the 30 % of the total. If you want them to listen to you should show them just a few highlights about the theme you are talking about, just for them to focus on the subject, or you just let them read instead of continue talking otherwise you will distract them with your speech.