Change blindness is the failure to notice changes to the scene (or image) you are viewing. From Kelly: This is an interesting phenomenon and worth keeping in mind as it relates to demonstratives. It tells me that the presenter possibly needs to verbally point out the changes that occur when presenting a sequence of demonstratives [...]

A study published this summer (PDF) asserts that using animations in PowerPoint to control the rate of information on a slide may actually reduce comprehension by the audience. Even though the use of custom animation allows the introduction of new information incrementally the technique can adversely impact student learning experience when factual information is conveyed in the presentation.  Subjects shown [...]