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Behavioural design: what drives us to change

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Behavioural design is often referred to as nudging, which “proposes positive reinforcement and indirect suggestions as ways of influencing the behaviour and decision-making of groups or individuals” (source Wikipedia). The term was first coined by Richard Thaler, who based it on the “Fast and Slow Thinking” theories of Nobel Prize winner Daniel Kahneman.

Dr. BJ Fogg, founder of the Behavior Design Lab at Stanford University, has structured a model that can support and help researchers and designers to understand human behaviour in greater depth.

Fogg’s model offers interesting insights that can be used to encourage positive habits, which one wants to stimulate, or to discourage negative habits. In simple terms: people have to be sufficiently motivated and able to do something. In addition, there must be an element that drives them to act at the right moment.

This model is called the triangle of behaviour and consists of three elements: Ability, Motivation and Trigger (literally “trigger”, it can be understood as a trigger).
Each element contributes to the manifestation of the behaviour. Let us take a closer look at these three components.

Rappresentazione modello del comportamento di Fogg

Behaviour = Skill x Motivation x Trigger (Source: Pixelbento)

Fogg frames his model within a Cartesian plane where the vertical axis defines motivation and the horizontal axis defines skill level, thus defining the area of success for triggers. Different types of behaviour (Fogg created a grid of fifteen types) are characterised by different balances of these three, but the basic dynamic is that if motivation is high, a user is willing to do something difficult, when given an appropriate trigger. Likewise, if a behaviour is easy to perform, or if the level of skill is high, the motivation for action may be relatively low, again, assuming the trigger is the right one.

The rationale

Motivation is the only internal element and is the most challenging aspect to design.
It can differ from person to person, and if there is no motivation even the best behavioural design will fail. By assessing and understanding the motivation levels of people, we can design solutions that optimise their capabilities by creating triggers that can stimulate the intended behaviour.

With respect to motivation, the behaviour model highlights three main motivators: Sensation, Anticipation and Belonging, each of which is defined in a two-fold way.

  • a physical level: Sensation: pleasure / pain
     Behavioural economics reveals that we tend to assess the value of a loss of resources, such as money and time, as approximately twice as much as an equivalent gain.
    This is the cognitive loss-aversion bias.
  • an emotional level: Anticipation: hope / fear
    Fear is a behavioural factor which anticipates an expected negative outcome. For example, we may be given a flu vaccine because we are afraid of getting sick.
  • a social level: Belonging: acceptance / rejection
    Instagram is a classic example using social belonging as a motivation. It encourages us to continuously publish content, follow others and, in turn, win followers. It embodies our desire to be socially accepted.

The Triggers

Fogg identified “Six Elements of Simplicity” (or Skills) in his model:

  • Time
  • Money
  • Physical effort
  • Mental exertion
  • Social deviance
  • Non-routine

We can analyse each of these elements as reducing one’s ability, for example:

Time: we are more likely to carry out a behaviour that takes very little time than one that takes a lot of time.

Money: We are more likely to fulfil a task that costs less than one that costs a lot.
Here the context varies based on the purchasing power of the individual user.

Our goal is to minimise each of these “Elements of Simplicity” by designing quick, physically and mentally simple behaviours that do not require a lot of money or break social norms.

This is easier said than done, as the simplicity profile of each person is different and factors change not only in relation to the individual, but also in relation to the context.

The Triggers

The third factor in Fogg’s model is the Trigger. A trigger is something that instructs a person to do something now, it is an action that elicits an immediate response. Often overlooked (or taken for granted), Triggers are a vital aspect of persuasive product design. However, not all triggers work the same way. Fogg highlights three types of triggers: sparks, facilitators and signals. A spark is a trigger that motivates behaviour.
A facilitator simplifies the behaviour. And a signal indicates or reminds.

Spark Trigger: helps people who are skilled in the required behaviour, but not willing to complete it. An example of this is advertising: ads and marketing messages often want to push you to buy even if, at that moment, you do not want to buy.

Facilitating Trigger: helps people who are motivated, but lack the skills to finish a behaviour. Trigger facilitators make the task easier or at least make it seem easier.
A typical example is the instructions given when setting up a new phone or computer.
A facilitator not only triggers the action, but also makes the intended behaviour easier.

Signal Trigger: helps people who are motivated and able to complete a behaviour.
The main purpose of the signal trigger is to make us more aware or remind us of something we can and want to do. It could be a calendar reminder or a text message notification.

As target groups, we are more tolerant towards Triggers when they are signals or facilitators. While sparks may disturb us as they will try to motivate us to do something we did not intend to do.

As designers we have the task of proportioning and choosing the right trigger correctly and sending it at the right time.

Further information:

For more details on the Fogg model, please refer to the author’s main website,

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