Latest / The Copywriting Podcast with Fexingo: Sales Letters, Headlines, and Persuasive Writing / How a Single Word Change Tripled Direct Mail Response
Transcript
- Lucas: There's a direct mail test from the late nineteen-eighties that I think about at least once a month. A financial newsletter company mailed a control package with a headline that started with the phrase 'How to' — standard stuff. Then they tested a version that replaced 'How to' with 'The secret of'. Same offer, same body copy, same envelope. The response rate nearly tripled. Luna: Tripled? That's not a tweak, that's a different league. Do you remember the exact numbers? Lucas: The control pulled about zero point eight percent. The test pulled over two point three percent. On a mailing of a hundred thousand pieces, that's the difference between a losing campaign and a very profitable one. The newsletter was called 'The Money Report' — a small operation out of Florida. The copywriter was a guy named Bob Hines, who'd been writing financial promos for about ten years at that point. Luna: And the only thing that changed was the first three words? No new promise, no different offer? Lucas: Nothing else. Same lead, same bullet points, same guarantee. Just that one phrase swap. And it's stuck with me because it's such a clean illustration of the curiosity gap — the idea that people are drawn to information they feel they're missing. 'How to' implies you're about to learn a process. That's useful. But 'The secret of' implies there's hidden knowledge, something exclusive, something few people know. That's emotionally different. Luna: It frames the reader as someone about to join an insider group rather than someone about to receive instructions. That's a status play, almost. Lucas: Exactly. And the financial newsletter audience was perfect for it — people who believed the market had secrets, that the pros knew something they didn't. 'The secret of' plugged directly into that anxiety. Now, I should say, this test worked because the body copy delivered on the promise. The newsletter actually did contain proprietary trading signals. So the headline wasn't lying — it was just framing the same truth more powerfully. Luna: Right, because if the body had been generic, the gap would have collapsed the moment someone read the first paragraph. The headline sets an expectation, and the copy has to meet it. Lucas: That's the danger with the curiosity gap — you can overshoot. If the headline promises a secret and the first paragraph is 'First, open a brokerage account,' the reader feels tricked. The gap closes not with satisfaction but with disappointment. Bob Hines was smart enough to match the tone all the way through. The lead was something like 'Inside this letter is a strategy that has returned seventeen percent annually for the past six years, and almost no one on Wall Street uses it.' That's a secret. The rest of the letter just proved it. Luna: So the word choice mattered, but only because the copy structure supported it. I wonder if that same test would work today, in email subject lines. Lucas: Some version of it probably would. I've seen similar A/B tests in email where 'How to' underperforms 'The trick to' or 'What doesn't want you to know'. The curiosity gap is actually stronger in email because you have even less space to establish intrigue. But there's a catch — email spam filters flag words like 'secret' and 'trick' more aggressively than they did in the eighties. So you might need a subtler synonym. 'Little-known', maybe. Or 'Uncommon'. Luna: That's a good point. The channel changes the vocabulary constraints. But the principle stays the same. I'm thinking about a campaign I saw for a B2B software company — they tested 'How to reduce churn by twenty percent' against 'The method most companies overlook to reduce churn'. The second version had a higher open rate and click-through. Same product, same audience, just framed as an overlooked method rather than a how-to. Lucas: That's a perfect modern parallel. The 'overlooked' frame creates that same insider feeling. And notice they didn't use the word 'secret' — they used 'method most companies overlook'. That's more appropriate for a professional audience. The core insight is the same: people want information that feels exclusive, even if it's just a reframe of common knowledge. Luna: So how do you know when to use 'how to' versus the secret frame? There must be situations where the direct instructional approach wins. Lucas: Absolutely. 'How to' tends to win when the audience is actively searching for a solution and wants efficiency. If someone has a specific problem — say, a small business owner trying to file their own taxes — they want clear steps. 'How to file your quarterly taxes in forty minutes' is better than 'The secret the IRS doesn't want you to know'. The secret frame works better when the audience is skeptical, or when the topic is something they think they already understand. It re-engages them by suggesting there's a layer they haven't considered. Luna: That's useful. So the 'how to' frame is for the motivated beginner, and the 'secret' frame is for the jaded intermediate. Lucas: Roughly, yes. And the key is knowing which audience you're writing to. The Money Report was targeting people who had already tried other newsletters and been disappointed. They were skeptical. So the secret frame was exactly right. If you're writing for first-time investors, you'd probably want a more straightforward approach. Luna: I want to come back to the idea of the curiosity gap and how it applies to modern copywriting. You mentioned email subject lines — what about landing page headlines? Same principle? Lucas: Same principle, though landing pages have the advantage of more real estate. You can combine both frames. A headline like 'How top performers cut their meeting time in half' works fine. But 'The meeting strategy that top performers use — and why almost no one else does' creates a gap. The reader thinks, 'I use meetings all the time. Am I missing something?' That's the hook. Then the subhead or first paragraph can deliver the how-to part. The best landing pages often do both: create a curiosity gap in the headline, then satisfy it with specific steps. Luna: That's a good structure. I've also seen tests where the word 'why' outperforms 'how' in headlines. 'Why your emails aren't getting replies' versus 'How to get more email replies'. The 'why' version implies there's a hidden cause, a mistake you're making without realizing it. That's another kind of curiosity gap. Lucas: Yeah, 'why' is powerful for diagnostic content. It taps into the desire to understand the root cause. And it often works better for an audience that thinks they already know the basics. If someone already knows how to write an email, telling them how won't help. But telling them why their existing approach is failing — that grabs attention. Luna: It's fascinating how small word choices can completely change the psychology. I want to ask about the ethical side — is there a line where the curiosity gap becomes manipulation? Lucas: There is, and it's crossed when the headline promises something the copy can't deliver. If you say 'The secret to doubling your income' and then the method is 'work more hours', that's manipulative. The reader feels cheated, and they won't trust you again. But if you have a legitimate insight — a real method that's underused — then framing it as a secret is just good communication. You're helping the reader recognize the value of what you're offering. The line is basically the same as the line between marketing and fraud: are you accurately representing what's inside? Luna: That's fair. And I think that's what made Bob Hines's test ethical — the newsletter really did have proprietary signals. The secret was real. Lucas: Exactly. And that's the takeaway I keep coming back to. The word change from 'how to' to 'the secret of' didn't invent value. It just made the existing value more visible. That's the job of a headline — not to inflate, but to frame. To say, 'This thing you're about to read? It matters more than you think.' Luna: And if these kinds of marketing conversations have sparked something you've actually used in your own work — a headline tweak, a framing shift, a new way to think about your audience — we'd love to know. It's also the kind of feedback that keeps this show going, honestly. If you find value here and want to support the ad-free format, you can buy me a coffee dot com slash fexingo. No pressure at all. Just a way to keep the conversations coming. Lucas: Yeah, and we don't run ads, so listener support is what makes this sustainable. We appreciate everyone who listens, whether you chip in or not. Now, back to that phrase swap — I want to talk about one more test that surprised me. Luna: Please, go ahead. Lucas: There's a test from the early nineties where the same financial newsletter tested 'How to make money in a falling market' against 'The secret to making money when the market drops'. The second version won by about eighty percent. But then they tested a third version: 'How to profit from the next market crash — using a little-known strategy'. That one beat the secret version by another forty percent. So it's not just the word 'secret' — it's the specificity of the hidden knowledge. 'Little-known strategy' is even more concrete than 'secret'. It tells you there's a specific tactic, not just general insider info. Luna: Interesting. So the more specific the curiosity gap, the stronger the pull. 'Little-known strategy' implies a defined, learnable technique. 'Secret' can feel vague. Lucas: Right. And that's the next layer of the lesson. The word change from 'how to' to 'the secret of' was a big leap. But you can keep refining. The best copywriters are always testing one word at a time, looking for that extra percentage point. It adds up. Luna: I think that's a good note to end on. Small words, big gaps, constant testing. Lucas: And always asking: what does my reader think they know — and what do I want them to feel they're missing?