Hardwired into our mental DNA is the to reciprocate when we were seeing the gift the regions of the brain associated wish the motion in decision-making light up studies on the social and psychological aspects of this activity show the receiving the gift triggers a cognitive conflict that must be resolved the easiest way to resolve the conflict is to give something in return of equal or greater value in psychology is known as the theory of reciprocity or social reciprocity the Coca-Cola experiment is probably the most well-known study on reciprocity it was published in 1971 by this rague in this study the participants believed they were there to evaluate paintings also the room was a fellow participant Joe Joe was really reagan's assist first lady manipulated the degree to which a participant liked Joe by having the subject over here Joe being