The Spark Plug Theory of Marketing

Henry Ford was not a guitarist.

Consider that assertion for a moment. What do you suppose it means? That Ford was a pianist? That his musical tastes leaned more toward Big Band? That he was lacking in manual dexterity? Any (or all) of those explanations may be true, but in the context of the ad that my firm created for Pimentel, a small, family-owned guitar maker, it’s a poetic way of pointing out that these handcrafted instruments of beauty don’t roll off an assembly line. (You can take a look at the ad by clicking on the photo at the right of this column.)

It’s not a big leap to come to that conclusion; anybody who knows about Henry Ford and his contribution to the Industrial Revolution would likely draw it. But as simple as interpreting the headline is, it does require involvement from the reader. That’s what makes the ad work.

Voltaire once said, “The best way to be boring is to leave nothing out.” That’s one reason why ads tend to fall flat, at best, and annoy at worst—companies cram too much into them trying to make their case, or expect that they can open and close the sale in one fell swoop. But nobody wants to be told what to think. The best advertising is like a spark plug that leaves a small gap for the audience to fill in for themselves.

Start a Thought

As a marketer it can be tough to resist the temptation to complete the picture, but the most effective advertising merely starts a thought, allowing the audience to finish it. By drawing their own conclusions, they’re more likely to be convinced, and the result is more likely to stick because they invited the thought into their minds rather than raised their defenses to shut it out.

Ernest Hemingway was once challenged to tell an entire story in a mere six words. His solution, “For sale: baby shoes, never used,” is a sublime example of the spark plug principle. Hemingway leaves it to the reader to fill in the gaps—the tragedy, the sadness, the grief—of his short but compelling tale.

No two readers imagine what happened in exactly the same way, making each story, by definition, personally theirs. Since they own it, they’re likely never to forget it—and they just might share it with someone else.

Remember those connect-the-dots illustrations that delighted us as children? Simply by taking a pencil and drawing a line from one dot to the next, then to another, and another, we played a part in bringing a picture into being. As we did, we experienced the joy that comes with creation. Even though the dots were laid out by somebody else, the act of connecting them made the picture our own, and sometimes Mom even pinned the results to the refrigerator door.

Motel 6 Classic

Twenty-five years ago, in his first radio recording session for Motel 6, humorist Tom Bodett ad-libbed a line that has gone down in advertising history: “We’ll leave the light on for you.” Think about that quip from a spark plug perspective; Bodett was not simply saying that when you pull into a Motel 6 at night it won’t be dark. Those seven words encourage listeners to envision ways in which the folks at Motel 6 will welcome weary travelers, making sure the sheets are clean, rooms are safe, and whatever else they care to imagine.

Allowing listeners to finish the story involves them in the outcome and helps the commercials work more effectively for each person. That’s one reason why the campaign has received more than 150 awards and has been running for more than two decades.

As marketers, it’s our job to think ahead and set the gap in such a way as to enable our audience to complete the loop. If we don’t know (or respect) our audience well enough, we could easily miscalculate. Here’s how the real-life spark plug experts at the Green Spark Plug Co. in Cheshire, England, put it: “The gap adjustment can be fairly critical. A narrow gap may give too small and weak a spark to effectively ignite the fuel-air mixture, while a gap that is too wide might prevent a spark from firing at all.”

Minding this gap is not an easy thing, and as creators of advertising we have our work cut out for us. But it’s much more fun (and effective) to spend our energy influencing people toward the right conclusions rather than presuming we can tell them what to think. Hemingway said: “If a writer knows enough about what he is writing about, he may omit things that he knows. The dignity of movement of an iceberg is due to only one-ninth of it being above water.”

When we allow the audience to connect the dots, complete the story, and fill in the gaps, they own the outcome. It’s true in children’s art, it’s true in literature, and it’s true in advertising. All we need to make it work is imagination, respect for our audience, and the confidence that when they complete the loop it will spark them to action.

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