persuasion
Commitment and consistency
What is the commitment and consistency principle?
People feel a strong pull to act in line with what they've already said or done. So a small, early commitment - a tick, a tiny first step, a stated preference - makes a larger, consistent request far easier to agree to later. It's the "foot in the door": the first small yes paves the way for the bigger one.
Also known as: commitment and consistency, consistency principle, foot in the door, commitment bias
The demo
The same request, reached two ways. Try the cold version, then the one that asks a tiny something of you first - and notice how differently the big ask lands.
What this demo shows (text version)
The same request - start putting a little aside each month - is reached two ways. In the "cold ask", the full commitment is put in front of you straight away, and it's easy to decline. In "small step first", you're asked a tiny question you readily agree with ("Would you like to save more this year?"), and only then is the bigger request made - now framed as simply following through on what you just said.
After the small yes, the larger ask feels like consistency rather than a new decision, so it's far easier to accept. That's commitment and consistency - the foot in the door. It's genuinely useful for easing people into something they want, but the same lever can manoeuvre people into agreements they'd have refused cold. The honest test: was the first step freely taken, and does the bigger ask serve them?
A small commitment makes a later, consistent one much easier to secure - which is why onboarding asks an easy first question before the real request, and why "foot in the door" works. Used well it lowers the barrier to starting something the user genuinely wants; used badly it manoeuvres people into agreements they'd otherwise refuse. The line is whether the bigger ask serves them or just you.
After the tiny first yes, the bigger request felt like simply following through - of course you'd continue; you'd already started. Asked cold, the very same request was easy to wave away. Nothing about the offer changed; you'd just made a small commitment first, and consistency did the rest.
The pull is toward self-consistency: once we've taken a position - even a trivial one - acting against it feels like contradicting ourselves, so we tend to stay the course. A small first step also shifts identity ("I'm someone who does this"), which a later, larger request can lean on without feeling like a leap.
It's why good onboarding asks for something tiny before something big: complete one easy field, make one small choice, take one quick action - and momentum plus consistency carry you into the rest. Progress indicators and "you've started, finish up" nudges work the same lever, turning a daunting task into a sequence of small consistent steps.
The dark version manufactures a commitment to exploit. A pre-checked "I agree", a trivial opt-in quietly reframed as consent to far more, a free trial that banks on your reluctance to act against having signed up - each weaponises consistency against the user's interest. The honest test: was the first step freely and knowingly taken, and does the bigger ask serve the person who took it?