Powerpoint presentations, beloved of the business executive, are so ubiquitous that there are even PowerPoint presentations on how to do a PowerPoint presentation. Now research claims to have proved what millions of bored workers have suspected all along - they have little power and even less point. According to the report, the brain cannot cope with having too much information thrown at it at once. Having someone speak and point to a screen full of facts and figures at the same time causes it to switch off. A speech would be far less of a waste of time, the research claims. The study, at the University of New South Wales, branded PowerPoint presentations a disaster and called for them to be scrapped. Prof John Sweller said there was a scientific explanation for a room full of PowerPoint viewers yawning and looking at their watches after a couple of minutes. He said: "If you have ever wondered why your eyes start glazing over as you read those dot points on the screen, at the same time words are being spoken, it is because it is difficult to process information if it is coming in the written and spoken form at the same time." PowerPoint is a Microsoft program for PCs. It allows a presentation to be designed in a series of slides which are beamed to a wall or a big screen for the speaker to use as visual aids. But what tends to happen is that the speaker - often a nervous executive, trainer or sales boss - merely repeats the same words as contained in the slides, so the audience gets the information twice. Speakers also tend to fill the screens with pie charts, graphs, slogans and bullet points, often in capital letters for emphasis. That kind of repetition makes the brain switch off, which could explain why so many audiences end up bored out of their minds during vital but dull displays at conferences. Prof Sweller said notes should not be read aloud from a display. Doubling up does not double the chances of the message getting across. He added: "The use of the PowerPoint presentation has been a disaster. It should be ditched. It is effective to speak to a diagram, because it presents information in a different form. "But it is not effective to speak the same words that are written, because it is putting too much load on the mind and decreases your ability to understand what is being presented. "PowerPoint can backfire if the information on the screen is the same as that which is verbalised because the audience's attention will be split." Prof Sweller believes there is a limited amount of information that a person can process at once.