Why Do Presenters Look at the PowerPoint slide on the Screen?

It never ceases to amaze me how often presenters look at the PowerPoint slide projected on the screen. It happens when they put up a new slide or put new text or an object on the slide. They have the laptop screen in front of them and can see it perfectly clearly, but they feel compelled to turn their back to the audience and look at the projected image. Is it because they don't trust that what is on the laptop is really on the screen? What makes it worse is that the presenter usually starts speaking while they are facing the screen, so the audience can't hear them at usually the most critical time of any slide. Trust the technology or use your peripheral vision to see something happen on the screen and keep facing the audience. It's not about your slides, it's about the audience. It almost looks like some presenters turn around just to admire their "cool" slides in large size. Next time you present, please keep looking at the audience, glance at the laptop to check that the right slide is displayed, but don't turn around to speak to the projected image on the screen. Your audience will thank you.