What Causes Behavior Change?

The Fogg Behavior Model shows that
three elements must converge at the same moment for a behavior to occur: Motivation, Ability, and Trigger. When a behavior does not occur, at least one of those three elements is missing.
BJ Fogg Behavior Model Grapic

Using my Behavior Model (FBM) as a guide, designers can identify what stops people from performing behaviors that designers seek. For example, if users are not performing a target behavior, such as rating hotels on a travel web site, the FBM helps designers see what psychological element is lacking.

The FBM also helps academics understand behavior change better. What was once a fuzzy mass of psychological theories now becomes organized and specific when viewed through my Behavior Model.

The FBM highlights three principal elements, each of which has subcomponents. Specifically, the FBM outlines
three Core Motivators (Motivation), six Simplicity Factors (Ability), and three type of Triggers. The subcomponents define the larger elements. For example, in the FBM the word Ability refers to the how the six Simplicity Factors work together in the context of a Trigger.

Many other people have proposed ways to understand persuasion and behavior change, dating back to Aristotle in ancient Greece. What makes my Behavior Model different from previous work? First, the FBM shows how behavior is the result of three specific elements coming together at one moment. Next, the FBM explains the subcomponents of each element. In addition, the FBM shows that motivation and ability can be traded off (e.g., if motivation is very high, ability can be low). Finally, the FBM applies most directly to practical issues of designing for behavior change using today’s technology.

If you know of work related to the FBM, please share it on the page for
references and connections. This will be an ongoing resource for people designing for and studying behavior change.

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The Fogg Behavior Model is part of a larger system that helps people design for behavior change. To see my related work (and a lot more), go to

You may also be interested in joining my
Behavior Design Boot Camp.


BJ Fogg, Ph.D.
Persuasive Technology Lab @ Stanford University