Cialdini's commitment and consistency principle states: once people take a position or action, they feel internal pressure to behave consistently with that commitment. On landing pages, this translates into a powerful pattern — get visitors to take a small, easy action first, and they're significantly more likely to take a bigger action next.
This is why multi-step forms often outperform single-step forms, even though they require more total effort. Once someone fills out step 1 (usually the easiest fields — name and email), abandoning at step 2 feels inconsistent with the commitment they just made. They've already started; now they want to finish.
Applying this without being sleazy
The "foot in the door" technique is the classic application. Start with a free tool, quiz, or assessment. The visitor invests time and attention. Now offering a paid upgrade or demo request feels like a natural next step, not a cold ask. Typeform built an entire business on this insight — their multi-step, one-question-at-a-time format leverages commitment with every click.
The key distinction: commitment works when the initial action provides genuine value. A free audit that delivers real insights earns the right to ask for an email. A "click here to continue" that reveals nothing but a signup form feels like a bait-and-switch. The commitment has to feel like progress, not a trap.