Big in Japan
In Japan, the way people read is fundamentally different to how we read in the west, and it's not just the vertical orientation of the lines. You can see sense how reading is different in the design of newspapers.
The writing systems used in East Asia have turned people into expert information scanners; they can digest very dense information very quickly.
If you give a presentation in Japan, it's quite common (and expected) to put everything and the kitchen sink onto a slide (I learned this the hard way, when training designers there!). The onus is on the reader to scan and identify what's important, because that's how people are used to consuming media.
In the West, with our slower, horizontally-oriented style of reading, this doesn't work. People aren't used to scanning large amounts of information quickly. And yet... when we put a lot of information on screen, we beg them to read it all. Which stops them listening to us. Like this:
It's all about the mode
There's nothing intrinsically wrong with the above example, it just depends on what mode of communication you're going for. Slides are often prepared for two modes of communication at the same time: to send (reading) and to present (listening). When we mix these two modes up, we're either asking people not to listen to us (because they're too busy reading) or failing to give them enough detail.
Tools like Keynote and Powerpoint have done us no favours here. Imagine if they had modes of communication built in - you could switch between reading and presenting mode, and the tools would work out what level of detail was needed on screen (IA Presenter kind of encourages this...!).
Some organisations are very strict about the word count on slides. Laura Yarrow (the head of design at GDS), told me that their rules force presenters to use no more than ten words per slide (more about their approach here). Here's an example from my book that is getting there, in terms of minimalism.
In this example, I might fade-in the quote and image on the right only after I've explained the insight on the left. So I'm not too strict about how minimal we should be with words on screen; not least because you can control how much reading is going on by other means, when you need to.
Optimise for listening
So when you're presenting and you want people to pay attention to you, make sure what you're presenting isn't setup to distract them with reading. Optimise for listening. That is, unless you're in Japan. ;-)