Lirio, The Behavior Change Company, delivers results by drawing insights from hundreds of behavioral biases and theories. Our Bias Brief series walks through specific biases one by one, each thoughtfully selected from our long list of insights. Read on for a brief rundown on the chosen bias, complete with examples and instructions for putting it into action to help your audience do better.
Bias #178: Commitment & Consistency; 4.5-minute read
Defined:
Commitment & Consistency Bias: People’s strong desire to be—and to appear—consistent with what they have already done. Once people have made a commitment or taken a stand, they feel pressure to behave consistently with that commitment.
Described:
People often say that past behavior is the greatest predictor of future behavior. But why?
It’s because our actions, beliefs, and commitments help us form our self-perception, and how we see ourselves guides our choices. So, with New Year’s resolutions just around the corner, if you want to change someone’s behavior, one method is to change the way they see themselves. You can do that simply by getting them to make a commitment.

That’s what Stanford researchers Jonathan Freedman and Scott Fraser discovered with an experiment they ran in 1966.1 In a neighborhood in Palo Alto, California, researchers claiming to be from the Community Committee for Traffic Safety were sent door to door asking homeowners to sign a petition promoting safe driving. Some homes were skipped to create a control group.
Two weeks later, a different person visited each house claiming to represent a group called Citizens for Safe Driving. They asked homeowners if they would install a very large, unattractive sign in their front yard that said, “Drive Safely.” The results were revealing:
- With the control group—the homeowners who had not received the first visit or signed the safe driving petition—only 17% agreed to install the “Drive Safely” sign.
- Of the homeowners who had received a visit and had signed the safe driving petition two weeks prior, 76% reinforced their commitment to safe driving by agreeing to the sign!
As it turned out, the homeowner’s view of the “Drive Safely” sign depended on their view of themselves.
While most of the homeowners probably looked at the sign and thought, “Do I really want that thing in my yard?” (an easy “No” for those who had not signed the petition), those who had signed the petition were motivated by another question: “What would a person who is committed to safe driving do?”
That person—the one they had become by signing the petition—would accept the sign. So, they did.
“What you think may change what you do, but perhaps even more important, what you do will change what you think.”
– Charlie Munger, Vice Chairman of Berkshire Hathaway
When to use commitment & consistency:
Anytime you want/need a person or people to comply and change their behavior voluntarily—without having them feel pressured—apply commitment and consistency.
How to use commitment & consistency:
You can apply commitment and consistency using something called the foot-in-the-door (FITD) technique. Start by persuading the target (person or people you want to comply) to agree to a small request. When they do, they will be more likely to comply with a larger, related request. Like in the example above, when someone signs a safe-driving petition (small request), they are more likely to display an oversized “Drive Safely” sign in their yard (large request).
Here are some factors that enhance the effectiveness of the FITD technique:
Align the Requests
For the technique to work, the initial, small request must be related to the large request. Signing a safe driving petition and putting a safe driving sign in your yard work because they’re related. Signing an anti-litter petition and putting a safe driving sign in your yard are unlikely to work because they are unrelated.
Require Action
The small request is more influential when it requires an action. Asking people to sign a petition is more influential than asking them to state their opinion. The more effort that goes into a commitment, the greater its ability to influence future behavior.
Make it Public
Commitments are more powerful when they are public. You could amplify the influence of someone’s signature on a petition, for example, by publishing the petition online for all to see.
Phrase it as an Inner Choice
Whenever possible, phrase commitments as an internal choice rather than an external restriction. “I don’t litter” (an internal commitment) is more powerful than “I can’t litter” (an external restriction). Avoid rewards and threats, which add external pressure and may reduce commitment.
The takeaway:
Whether you are looking to increase patient adherence, boost energy efficiency program participation, or help a loved one achieve a desired behavior, commitment and consistency bias can be a helpful tool for achieving better outcomes.
About the author:
This Bias Brief was written by Greg Stielstra, the Senior Director of Behavioral Science at Lirio. Greg is a behavior change expert and published author with over 25 years of experience in marketing and engagement.
References:
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