Social engineering relies heavily on the six principles of influence established in Robert Cialdini’s Influence: The Psychology of Persuasion:
• Reciprocity – People tend to return a favor, hence the pervasiveness of free samples in marketing.
• Commitment and consistency – If people commit to an idea or goal (orally or in writing), they are more likely to honor that commitment because it’s now congruent with their self-image. Even if the original incentive or motivation is removed after they have already committed, people will continue to honor the agreement.
• Social proof – People will do things that they see others doing.
• Authority – People will tend to obey authority figures, even if they’re asked by those figures to perform objectionable acts.
• Liking – People are easily persuaded by others that they like.
• Scarcity – Perceived scarcity will generate demand. For example, by saying offers are available for a "limited time only," retailers encourage sales.