Reciprocity: People tend to want to comply with a request if they’ve already received a favor.
Commitment and consistency: People like to remain consistent with past behaviors and commitments.
Social proof and consistency: People tend to follow the behavior they see in others.
Authority: People unconsciously follow advice from perceived authority figures.
Because: People subconsciously respond to requests when the word “because” is included. Always provide a reason for the request.
Via Jean-Philippe D'HALLUIN, David Hain