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.
Behaviour change elements: motiviation, ability, trigger
Core Motivators: pleasure/pain; hope/fear; social acceptance/rejection
Simplicity factors: time; money; physical effort; brain cycles; social deviance; non-routine
Triggers: facilitator; spark; signal