Google "seven-minute rule" and you'll find a number of references. Not all are associated with learning or training, but a number of them are. It's amazing how this has caught on/stuck around/been discovered by others over the years. It's amazing to me, because I established the seven-minute rule for video-based education in the early 1990s. I think I was 18 at the time (Did I do that math right?).
The rule was created for use by a group of content and continuing education developers, and it went something like this:
Seven minutes is as long as you want a segment to run. Period.
It may seem like an oddly ironclad rule for a relatively arbitrary use, but it actually came from arduous research through mountains of data. Well, it wasn't exactly scientific research, and it wasn't exactly data, but there was a mountain of it and it was arduous. I was hired to produce a daily training program, delivered via satellite, that was formatted like a morning show. We had co-hosts, guests, sets with couches, and regular training segments. One of my first tasks was to wade through an enormous library of 25-minute motivational videos and turn them into short videos that could be played inside our 15-minute segments.
There were hundreds and hundreds of these videos, all by top motivational speakers of the day, from Zig Ziglar to Tony Robbins. What I found amazed me. All of these speakers, and I mean all of them, spoke in easily-editable segments of 4 to 7 minutes in length. This was not a requirement imposed on them, it was their natural flow. They would start a story or a thought, build it up, make a point, wind it down, and transition to the next thought... in 4 to 7 minutes. Every time.
So I got to thinking about that, about this natural cadence of the world's best speakers, and decided it should apply to all our other segments as well. After all, if Steven Covey and Les Brown don't drag a story out, why should we? Thus, the seven-minute rule.
I've used it ever since, in many different educational products and services, and it has held up well. And now you know (as another well-known speaker of yesteryear liked to say) ...the rest of the story.