Fogg Behavior Model

Also known as: B=MAT

framework · psychology · structured-empirical

Behavior occurs when motivation, ability, and prompt converge simultaneously.

BJ Fogg's Behavior Model, developed at Stanford's Persuasive Technology Lab and presented in his 2009 paper 'A Behavior Model for Persuasive Design' and his 2019 book Tiny Habits, holds that any target behavior occurs at the moment that three factors converge: sufficient Motivation, sufficient Ability, and a Prompt (originally called 'Trigger') to act. The formula is often written B = MAT (or B = MAP). The model includes a Behavior Activation Threshold curve showing the trade-off between motivation and ability — easier behaviors require less motivation, harder behaviors require more — and three prompt types (spark, facilitator, signal) appropriate at different points on the motivation-ability plane. Fogg's prescriptive insight is that increasing ability (making behavior easier) is generally more reliable than increasing motivation, leading directly to his Tiny Habits methodology of starting with extremely small versions of desired behaviors anchored to existing habits.

Originators

B.J. Fogg (Stanford Persuasive Technology Lab) high

Year / Decade

2009 (paper); 2019 (Tiny Habits book) high

Primary sources

Fogg, B.J. (2009). 'A Behavior Model for Persuasive Design', Persuasive '09, Fogg, B.J. (2019). Tiny Habits: The Small Changes That Change Everything high

Core components

Three factors: Motivation, Ability, Prompt (Trigger)
Behavior Activation Threshold curve
Three prompt types: spark (boosts motivation), facilitator (boosts ability), signal (reminder)
Tiny Habits methodology (anchor + tiny behavior + celebration)
Six elements of motivation
Six elements of ability (simplicity factors)

Primary use case

Behavior change design; product design for habit formation; health interventions; persuasive technology and UX design; foundation for habit-formation coaching and apps; behavioral-science applications in product management.

Common criticisms

Dependence on conscious motivation-ability decomposition contested by automaticity-based habit research (Wood, Neal)
'prompt' framing emphasizes external cues over internal states like cravings
the persuasive-technology lineage has been criticized for enabling addictive product design (Tristan Harris, Center for Humane Technology, where Fogg's students founded the critique movement)
empirical validation primarily from Fogg's lab and design case studies rather than independent replication
ability simplicity factors substantially overlap
'tiny habits' protocol has accumulated practitioner evidence but limited large-scale RCT validation.

Lineage

Siblings: Self-Efficacy Theory, Social Learning Theory