What is it?
We display an inherent preference for the existing state of affairs – we try to avoid change, and if faced with a choice tend to go with the flow of pre-set options or defaults. A default eliminates the need to make a decision.
How can I use it in my favour ?
This insight has revolutionized retirement savings in the United States: many more companies now enrol employees into retirement-savings programs by default (giving them the option to leave the program if they so wish), instead of making them fill out and submit a form in order to enrol. This small change has led to many more people saving for retirement than before, accomplishing something years of education, exhortation and matching contributions failed to achieve.
The evidence is overwhelming that presenting one option as a default increases the chance it will be chosen. This explains why marketers use defaults to persuade customers to receive email updates and offers.