Years ago I heard Billy Hanks make a case for taking notes on sermons. I may not have the numbers exactly right, but I think he said that, after 48 hours, we forget around 95% of we just hear. If we hear something and write it down we retain about 50% of it after 48 hours according to what I remember about Hanks' numbers. (I did write the numbers down, but its been way more than two days ago that I heard them.)
Hanks referred to the verse in which Jesus spoke of casting pearls before swine. He said that he is convinced that if we could look with spiritual eyes around our church facilities we would see all these spiritual pearls laying about that the congregation failed to take home with them.
I am not at all comfortable with the notion that the members of the congregation are swine in the Hanks' analogy. However, his overall point is valid.
Most of my undergraduate college days were spent in the field of education and what I learned there confirms what Hanks' says. The more senses we involve in learning the better we retain the material. That's why I have have for years inserted in our church bulletins "listener guides" which include key statements from the sermon with key words left blank in each statement. As congregants listen, they fill in the blanks. Not everyone in the congregation uses the listener guides but many have told me the guides help to focus their attention and to remember what they have heard.
Almost two years ago we added a contemporary service that meets in our fellowship hall and, from day one, we used a PowerPoint presentation not only to display song lyrics but along with the sermon as well. We provide the same listener guides in this service as those used in the other services, but, in the contemporary service, the listener guide statements are projected onscreen as they come up in the sermon. I also add other PowerPoint slides with pictures along with a movie clip now and then.
In the contemporary service, then, even more senses are involved in the learning that takes place during the sermon. The congregation hears my words, sees some of them onscreen and writes some of them on paper. Now we are working on adding video capability to our sanctuary allowing us to use PowerPoint with the sermons preached in our two traditional services so that those worshippers may have enhanced opportunities to retain what they hear and see.
PowerPoint presentations do add to sermon preparation time, but I enjoy the process and I believe the slides aid learning. Hopefully hearing the message, seeing the message and writing the message combines to assist worshippers in taking a few spiritual pearls home with them.