Perhaps human being have been speaking long enough so that natural selection has improved our oral comprehension skills. We probably have not been reading long enough and we certainly have not been listening to PowerPoint presentations long enough. Audiences are not good at listening to slide presentations and it is up to the speaker to help them.
There are five listening challenges facing the audience:
1. Multi-tasking
2. Information overload
3. Slide transitions
4. iphones
5. Slide fatigue
I'll summarize these below, but earlier Tips can also help address them, see tips from December 4, September 2, and August 25.
Multi-tasking: A slide presentation asks the audience to read the slides, listen to the speaker, watch the speaker, and watch the pointer. Unless the speaker can create a synergy among these these modes there is no point in having a slide presentation.
Information Overload: The audience does not know what the next slide will contain. Each slide is a surprise. So it is very easy to overwhelm them with too much information.
Slide Transitions: Slides break up what should be a coherent narrative into micro narratives (individual slides). It is up to the speaker to provide the words that bridge one slide to the next and keep the story coherent.
iphones: The audience doesn't hear everything you say and nowadays they are texting or looking out the window. You need to have device that helps the audience "hop back on" to the talk if they have gotten lost. Think about repeated use of an outline slide with arrows showing which part of the talk is coming up.
Slide Fatigue: more on this in the next tip. Just remember that listening to a slide presentation is a passive activity and people generally don't learn well as passive listeners. This problem is unavoidable, but we can minimize it.