[Air-l] Research on Effects of Power Point?

Does anyone know of research (formal or otherwise) on the effects of Power Point formatting on emerging writing styles, logical argumentation skills, or comprehension? I'd be grateful for any data for (or against) the current adage that "Power corrupts but Power Point corrupts absolutely." With thanks, Naomi Naomi S. Baron Professor of Linguistics American University Washington, DC 20016-8045