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Commitment and Consistency

Commitment and Consistency


Firstly, commitment and consistency is a psychological tendency that people have to ensure consistency between actions and promises and their inner values and belief systems. It is one of Robert Cialdini’s 6 principles of persuasion and can be a powerful influence on our behaviour because of the importance of our self-image.

Consistency is a desirable personality characteristic which many people like to feel they demonstrate. Furthermore, people who are not seen as consistent are indecisive and hypocritical. This can result in people ignoring their own strongly held beliefs to avoid being seen as inconsistent. As a consequence, commitment and consistency can also lead to undesirable behaviour or outcomes. As people are so determined to be consistent they avoid thinking about the negative result of their behaviour.

1. The Evidence:

In 1972, the psychologist Thomas Moriarty, set up an experiment on New York City beach. A researcher would place a beach towel and a portable radio within 5 feet of a randomly chosen person. Within a couple of minutes of relaxing on the towel and listening to their radio, the researcher would get up and walk down the beach. A few minutes later a second researcher would walk past and grab the radio before attempting walk off.

When the first researcher made no attempt to ask the person nearby to look after their belongings only four out of twenty people attempted to stop the theft happening. When the researcher made a simple request to the person nearby to please “watch my things” this had a dramatic impact on their willingness to intervene to prevent the theft. Nineteen out of twenty people responded by challenging the thief.

2. Key things to note about commitment and consistency:

  • Commitment is the key driver of consistency.
  • Consistency is a valuable personality trait. People will sometimes even go against their own beliefs to be consistent.
  • Asking people for a favour can create that sense of commitment as it can change their self-image (e.g. I’m someone who gives to the needy).
  • Ask a question that says something about the type of person they are.
  • Start with a small request and people are more willing to comply with a larger request later.
  • Getting people to write something complementary about your brand helps to improve their perception of your product or service.
  • People assume that what people write reflect their beliefs about a topic.
  • Get staff to set their own targets and write them down on paper to benefit from commitment and consistency.

See our article on how commitment and consistency influence behaviour for more details on this principle of persuasion. Finally, the other principles of persuasion are:


  • If we do someone else a favour they will feel obliged to reciprocate.

Social Proof

  • We are heavily influenced by what other people are doing and the bandwagon effect means we may adopt a behaviour, attitude or product if it appears to be undertaken by many other people.


  • People are brought up to respect figures of authority. This means we are sometimes prone to following what people in authority tell us without proper critical evaluation.


  • People are more heavily influenced by people they like.


  • People have a tendency to value something more if they believe it is in short supply than if they think it is in plentiful supply. The power of scarcity may be driven by fear of regret which is a deeply unpleasant emotion and loss aversion.


Commitment and Consistency – What is the most powerful weapon of persuasion?

Behavioural change – Why do most attempts at behavioural change fail? 

Fogg Model – The Fogg behavioural model. 

Behavioural change frameworks – How to use behavioural science to create new habits.


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