GreenSpan Behaviors Preview

By the Stanford Behavior Wizard Team


An overview of GreenSpan behaviors and techniques for achieving them.

GreenSpan Behavior Overview

Green Span behaviorIf you want someone to commit to a behavior for a period of time, you are seeking a Green Span Behavior.

Examples include:

  • Health: Commit to use new toothpaste for a week.
  • Environment: Agree to carpool with co-workers for a month.
  • Commerce: Sign up for a six-month DVD subscription service.

To achieve a Green Span Behavior, three elements must come together at once. As the Fogg Behavior Model describes, you must Trigger the behavior when the person is both Motivated and Able to make the commitment. If any of these three elements is missing, the behavior will not occur.

Specifically, to succeed you should make sure these things happen:

  1. Boost motivation, while downplaying factors that de-motivate.
  2. Increase the ability to make the commitment.
  3. Deliver the trigger (request to commit) when motivation and ability are high.
In this case, the trigger is a request to commit to a do something for a fixed period of time. The first challenge is in framing the new behavior in a way that reduces costs (money, effort, time, etc.) and increases benefits. The second challenge is timing the trigger so it comes at the optimal moment, a concept called kairos in ancient Greece.
Fear is the primary reason people resist Green Span Behaviors (again, this means agreeing to do something for a period of time) comes mostly from fear (negative expectations). Will this new activity take up too much time? How much effort does the ongoing behavior require? And, what if I change my mind?
Savvy persuaders will downplay these fears.
— [new stuff needed below this point]
More often that not, a new habit is hardly internalized in the first attempt. As mentioned in the sections on Blue and Green habits, the transition from a new habit to a familiar habit is not automatic and often not very predictable. We gave the example of Vibram five fingered shoes which might be hard for Alice to get used to, but really easy for Bob. For the same reason, we can never pre-determine when Green Span ends and Blue Span begins.
More often than not, Green Span habits in their original form fail to get the target audience across the chasm of familiarity. The main reason is too much too fast. We discussed how complex or relatively hard Green habits could be broken down into simpler smaller Green habits that are easier to perform. For Green Span, in addition to breaking it down to simpler habits, stacking them on top of each other one at a time until the whole habit becomes automatic as we near the end of the established duration is the way to go. This would have a shade of Purple Span in it, where we increase the intensity of the habit.
Let us take an example to illustrate this strategy at work. Bob suffers from high cholesterol levels and has been advised by his physician to replace substitute eggs with Tofu for the next month. If Bob has never consciously consumed Tofu before, he is very likely not to take an immediate liking to Tofu. If he is accustomed to having eggs two times a day, he would do well to consume Tofu in place of eggs for just one of those two daily instances during the first couple of weeks. After he has acquired a taste for Tofu, he could replace the second instance with Tofu as well. The end result is that Bob has got used to a Green habit of eating Tofu during the four week duration.
As we see in the example above, we allow the motivation and ability for Green Span to build up more gradually. We might also disguise the Green Habit as a pseudo-Blue Habit. Additional triggers are introduced only when the target audience is ready for it. As with all Green habits, looping triggers for Green Span with other habits that the target audience might have increases the odds of success.

About Resource Guides

Our Stanford team created these Resources Guides to help people working on behavior change projects. We can make it easier for you to:

1. Learn about a specific type of behavior change

2. Create solutions for achieving that behavior

In the past, most designers and researchers guessed at solutions for changing behavior. And frankly most attempts failed. Today, rather than guessing at solutions, people who use our Resource Guides will have clear guidance.

Our Stanford team will continue to improve each of the 15 Resource Guides.  We welcome your input.

BJ Fogg, Ph.D. (
Director, Persuasive Tech Lab @ Stanford University



The Behavior Guides were created in 2010 and we are no longer updating or selling them.

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We hope you’ll also benefit from our more recent behavior design projects at:

–BJ Fogg, Ph.D. (
Director, Persuasive Tech Lab @ Stanford University


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