The rule of 7 is an idea in marketing that it can take hearing a message 7 times before we might take action.

Apparently the rule is from early movie marketing and while I don't know if I'd rely on the number it certainly seems a sensible idea to keep in mind that you can't expect people to take action the first time they hear your message — if you're trying to get people to try something new be it buying food, downloading your app, watching a movie, or a choosing an electric car, it takes a while and repeated exposure before you can expect it to pay off.

I can't remember where I heard it, but some advice I keep in mind when communicating is that by the time you're tired of saying it, others are just starting to hear it. It's not a bad thing to repeat your main message.

I learned about the Rule of 7 from the recent book Human Powered by Trenton Moss.

When putting an apple in the adverts on this sketch I was reminded that so often it's the things in the supermarket that are most healthy for us that don't get anyone shouting about them at all.

The rule of 7

One of the few books I've read all in one sitting is Metaphors We Live By, by George Lakoff. It was so fascinating learning how some of the most fundamental concepts we use to govern our lives are understood through metaphor. For example, one understanding of time is through our experience of space, so it seems natural to say, the hard times are behind us, or, I'm looking forward to the future. Or that Ideas Are Objects so you can give someone an idea, or toss a few ideas around. Or that Understanding Is Grasping, so you can get the idea, or get to grips with a concept.

Primary metaphor is a theory of how these metaphorical understandings may form when we're young as we associate abstract ideas with direct experience.

So it's natural that, when we're young, important things are often big and can exert control over us, leading to Important Is Big — Tomorrow's a big day, it's just a little thing, It was a huge deal.

Or experiencing warmth when we feel affection leading to Affection Is Warmth — he greeted me warmly, she gave me the cold shoulder.

Or how sometimes to know something is to see something, such as when we find out what's in a box by seeing what's in a box, leading to Knowing Is Seeing — I see what you mean, that's clear to me know, I'm feeling in the dark on that, let's shed some light on the matter.

Other examples of primary metaphor from Philosophy in the Flesh by Lakoff and Johnson include:

More Is Up — from seeing things increase in height when there is more of them eg the prices are rising

Difficulties Are Burdens — from difficult things literally being harder to deal with eg I'm feeling a bit weighed down at the moment

States Are Locations — from associating experiences with actual places eg I'm in a rut right now, but I'll get out of it.

Bad Is Stinky — from bad things actually smelling bad eg that movie stinks

Purposes Are Destinations — from achieving goals when we get somewhere such as having a drink eg I'm going to be a star but I'm not there yet

There are many more, plus the whole world of metaphor guiding how we construct our place in the world is fascinating.

The theory of primary metaphor is from Joseph Grady.

If the gif is annoying here are individual static images (and prints) for: Primary metaphor (print), Knowing Is Seeing (print), Affection Is Warmth (print)

Primary metaphor

Sonic booms are the noise heard when an object travels at or faster than the speed of sound.

As an object travels through the air it pushes air out of the way creating a shockwave — like the wake of a boat. If you were traveling fast in a plane you can imagine that as the shockwaves move away from you at the speed of sound (around 340 m/s), because you're traveling too, the ones in front of you compressed together a little.

As you reach the speed of sound, you're now traveling as fast as the shockwaves and they all bunch up forming a strong pressure wave.

An object traveling faster than the speed of sound leaves its shockwaves behind it in a cone-shape called a Mach cone after Ernst Mach.

To an observer on the ground the sudden change in pressure as the pressure wave passes is experienced as a loud boom.

There's quite a lot of subtlety to sonic booms and we're still researching technology to reduce them to make faster than sound travel less, well, noisy.

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Sonic boom