How One Underlined Phrase Lifted Response by 87 Percent

The Copywriting Podcast with Fexingo: Sales Letters, Headlines, and Persuasive Writing · Jul 23, 2026 · 10m · transcript

In this episode of The Copywriting Podcast, Lucas and Luna dissect a 1984 direct-mail letter from Boardroom Inc. that used a single underlined phrase to achieve an 87 percent lift in response. They trace the mechanical detail to the psychological principle of 'processing fluency' — the brain's preference for information that's easy to parse — and explain why underlining a key benefit can outperform bolding, italics, or font size changes. Lucas shares data from an A/B test run by the late copywriter Gary Bencivenga, who found that the underlined version pulled 3.2 times the…