I came across this article by Debra Dean Murphy on the use of powerpoint in worship. Some might call the first half of the article a diatribe. I think she makes some good points. I get particularly annoyed with powerpoint in sermons as it often feels more like a board presentation than an engagement with the Word of God. Having said that Hannah finds the use of visual images as helpful aid to her concentration and listening. Here's an extract from Murphy:
PowerPoint also conditions worshipers to act and react in visceral ways, so that the character of their bodily actions and emotional responses are at times downright Pavlovian. The screen, not the altar or cross, becomes the all-consuming center of attention, an object of intense fixation which triggers predictable reflexes and behaviors. When PowerPoint malfunctions, for instance, people become nervous and lost; they become conditioned to worry that it will malfunction. They find themselves thinking more about the screen and the technician at the soundboard than about the God whom they've come to worship and the larger worshiping body of which they are a part.
Indeed, PowerPoint makes worshipers less aware of the persons around them; they engage in less eye contact and other forms of human interaction for fear of missing something on the screen. (One might argue that hymnals, prayer books and bulletins potentially create the same sort of isolation or individualism in worship, and it's possible that they do. But the sheer dominating presence of a projection screen in worship works in concert with PowerPoint's client-driven bias to cater rather blatantly to the consumer/customer/individual.)
To use PowerPoint in worship is to unwittingly set up a competition between what's projected on the screen and the human voice doing the preaching, praying or singing. And it's a contest that PowerPoint always wins because, as Richard Lischer has observed, when the brain is asked to listen and watch at the same time, it always quits listening. What PowerPoint enthusiasts see as enhancing the worship experience--projecting pictures of water during a baptism or images of fire and wind on Pentecost--is instead a form of sensory overload that manipulates emotions and stifles imagination. It is difficult to cultivate an awareness and appreciation of ambiguity and mystery in worship when images are projected at strategically timed moments in the liturgy for the purpose of instructing worshipers what to think and feel.