Latest / The Copywriting Podcast with Fexingo: Sales Letters, Headlines, and Persuasive Writing / How One Handwritten Underline Beat a Full Digital Overhaul
Transcript
- Lucas: You get a sales letter in the mail. It's a clean, professional piece — nice paper, good typeface, well-structured paragraphs. And in the margin, right next to the main offer, someone has taken a blue pen and drawn a single line under the word 'guaranteed.' Luna: And that one line, one small handwritten underline, lifted response by 37 percent? Lucas: Exactly. This was a real test run by a financial newsletter publisher back in 2017. They took their control package — already a strong performer — and added nothing except that underline. No new copy, no new offer, no new envelope teaser. Just a pen mark. Luna: And they compared it against what? Lucas: Against a full digital overhaul of the same offer. A completely redesigned landing page with better imagery, shorter copy, bullet points, a testimonial carousel — the whole conversion rate optimization playbook. The digital version barely improved conversion at all, maybe two or three percent. The underline did almost forty times that. Luna: Okay, that's wild. But why? Why would a squiggle beat a thoughtful redesign? Lucas: There's a psychological principle at work here that copywriters have leveraged for decades but that digital teams often overlook. It's called the 'effort signal.' When you see a handwritten mark on an otherwise polished piece, your brain registers that a human being took the time to personally mark that page for you. Luna: So it's not about the underline itself, it's about what the underline implies — that someone chose to emphasize this specific point, just for me. Lucas: Right. It's a form of implied personalization. The reader thinks, 'This wasn't mass-produced. Someone looked at this and thought, yes, I want to highlight this part.' And that triggers a kind of trust shortcut. It's the same reason a handwritten P.S. on a typed letter can double response. Luna: We've talked about the P.S. before on the show. But this underline test feels even more subtle. It's not a full sentence, it's just a line. Lucas: And that's what makes it so powerful. The less overt the personalization mark, the more authentic it feels. A handwritten note can feel staged if it's too long. But a single underline — that's the kind of thing you might do to your own mail. It's familiar. It's not trying too hard. Luna: I remember a study from the early 2000s — the 'aesthetic-usability effect.' People perceive more attractive designs as easier to use. But this underline is the opposite: it's an intentionally imperfect mark that actually increases perceived trust. Lucas: Right. And that's the key tension. Digital teams spend thousands of hours polishing every pixel for a seamless experience. But seamless can feel sterile. The underline works because it breaks the polish. It introduces a deliberate flaw that signals humanity. Luna: So does this mean we should all start handwriting on our emails? That feels impractical. Lucas: No, but the principle translates. In email marketing, you can do something similar — a plain-text email that looks like it was written by a person, not a template. No images, no fancy formatting, just a conversational tone. Some of the highest-converting email campaigns I've seen are the ones that look the least designed. Luna: I've noticed that too. The emails that start with 'Hey, just a quick thought' outperform the ones with a hero image and a button. Lucas: Exactly. The underline is a metaphor for that entire approach. The question isn't 'how do I make this look more professional?' It's 'how do I make this feel more human?' And the answer often involves doing less, not more. Luna: Let me play devil's advocate though — doesn't this only work in certain contexts? Like, if you're selling enterprise software to a procurement committee, a handwritten underline might look sloppy. Lucas: Fair point. The context matters. The underline test was for a direct to consumer financial newsletter. The audience was older, mail-responsive, already primed to trust handwritten touches. But even in B2B, there's room. I've seen a B2B sales letter that included a handwritten sticky note from the CEO that said 'John, thought of you when I saw this.' It worked. Luna: Because it was a real note, not a printed facsimile. Lucas: Exactly. The authenticity can't be faked. If you try to mass-produce a handwritten effect with a font, it falls flat. The whole point is that it's one-of-a-kind. That's why the test used a real pen and a real person. Luna: So for someone listening who wants to test this, what's the practical takeaway? Try adding a handwritten element to your next direct mail piece? Lucas: If you're doing direct mail, absolutely. Test a handwritten underline on your main benefit, or a short margin note like 'This is the part I'd pay attention to.' But even in digital, you can apply the principle. Use plain text with occasional CAPS for emphasis — that's the digital equivalent of an underline. Or add a short, personal postscript to your email. Luna: And test it, don't just assume. The underline was tested against a control. That's the scientific part. Lucas: Always. The best copywriters are testers. The worst are guessers. And the underline test is a beautiful reminder that sometimes the smallest change — something that costs almost nothing — can outperform a massive redesign. Luna: Speaking of small things that make a big difference — it's worth mentioning that this show itself is supported by a small group of listeners who chip in through buy me a coffee dot com slash fexingo. It's not a big pitch, but it's what keeps the episodes ad-free. Lucas: Yeah, it's a real honest thing. A handful of people who find value in these conversations and decide to support it. And that literally funds the research and production. So if these marketing discussions have sparked something you've actually used, that's the same kind of small gesture that keeps it going. Luna: Exactly. No pressure, just wanted to share how it works behind the scenes. Lucas: So back to the underline — one more thought. The reason the test is so instructive is that it isolates a single variable. Most marketing tests try to change too many things at once. The underline test changed one thing. That's real science. Luna: And it disproves the assumption that 'more professional' always equals 'more effective.' Lucas: Exactly. The underline was actually less professional. But it was more human. And for a certain audience, human beats polished every time. Luna: So next time you're tempted to redesign your entire landing page, maybe just draw a line under your guarantee first. Lucas: And test it. That's the only way to know if it works for your audience. Thanks for listening, and we'll see you next time.