Behavioural design

The Fogg Behavioural Model

BJ Fogg founded the Stanford Persuasive Technology Lab. He's best known for his work on behaviour change and technology. The Fogg Behaviour Model is a simple expression of the three parts of any behaviour or behavioural change. It seems very obvious, but its simplicity provides a very useful framework for considering behaviour/change.

Behaviour = Motivation x Ability x Trigger

For a behaviour to occur, the following three things must occur at the same time:

  • the user is motivated to do whatever it is
  • the user is able to do it
  • there's a trigger that reminds/nudges/triggers the user to do it

All three are necessary, and they must be simultaneous. The trigger must come at a time when the user is both able and desirous of doing whatever you're trying to encourage.

There are two kinds of triggers: internal and external. When people think about triggers, they often focus on the external, but internal triggers can be much more compelling and hard to resist.

Internal triggers

  • Feeling bored
  • Feeling hungry
  • Feeling lonely

External triggers

  • SMS
  • Email
  • Alarm bell
  • App notification
  • day-to-day events, eg getting out of bed, putting on shoes, picking up keys

An exercise to generate trigger ideas

Ask everyone to come up with triggers in each of the following categories - OR using an adapted empathy map template.

  • Think
  • Feel
  • See
  • Hear
  • Smell
  • Taste (may not be relevant!)
  • Touch (may not be relevant!)

BJ Fogg has also observed that changing the trigger is usually more effective than changing the ability, and changing the ability is usually more effective than changing the motivation. Changing the trigger first enables you to check if that was all you needed to do, and ability and motivation are fine. Motivation is usually hardest to change, and hardest to measure. 

Note that Fogg's recommended priority order is somewhat different to typical business practice, which would focus on motivation first (ie, advertising), before improving the ease of use of their service.

It's quite common to be able to combine two or more of these three elements in a single intervention. For example, if you wanted to go for a morning run every day, you could put your trainers and running gear near to your bed. When you wake, the sight of them will act as a trigger, and having them already close to hand makes it easier to go for that run.

Building on this, Fogg produced a diagram to explain the relationship between the three elements.

The diagram shows that there must be high motivation, or high ability or both for a trigger to actually get people doing the desired actions. With a low motivation or low ability or both, the best trigger in the world will not work.

Fogg went one step further, and produced a 'behaviour grid' and 'behaviour wizard' building on the core insights of the model.

Fogg's behaviour grid

The grid and wizard together provide instructions for how to create particular types on behaviour change. For instance, for a black path change, you would reduce motivation or replace it with punishment, remove the trigger or reduce its noticeability, and make it harder to take the action.

How to use

The behaviour model can be used as the structure for generation of ideas about how to encourage/discourage certain behaviours.

I'd recommend starting with an analysis of the existing trigger(s), ability and reward. This can be accomplished by creating a user experience map/journey diagram, which should encapsulate the existing triggers and the action users subsequently take. You can overlay onto this all the  rewards users are getting at different points in the journey