We have already seen that one consequence of the rule is an obligation to repay favors. Another consequence, however, is an obligation to make a concession to someone who has made a concession to us. As my research group thought about it, we realized that was exactly the position the Boy Scout had put me in. His request that I purchase some $1

Three of the seven principles of influence—reciprocation, liking, and unity—seem particularly appropriate to the task.

The rule extends even to national conduct. The Magna Carta of 1215 employed it to define how, at the outbreak of a war, countries should treat merchants from the enemy nation: “If our men are safe there, the others should be safe in our land.”

Notice, as in the case of the turquoise-jewelry buyers, it was someone who wanted to be assured of good merchandise who disdained the low-priced item. I’m confident that besides the expensive = good rule, there’s a flip side, an inexpensive = bad rule that applies to our thinking as well.

Ethologists, researchers who study animal behavior in the natural environment, have noticed that among many animal species, behavior often occurs in rigid and mechanical patterns.

It wasn’t guests with an errorless stay who reported the highest satisfaction ratings and future loyalty. Rather, it was those who experienced a service stumble that was immediately put right by the hotel staff.

But even with a positive relationship cultivated and uncertainty reduction accomplished, a remaining goal needs to be achieved to boost the likelihood of behavioral change. In such a situation, the goal of motivating action becomes the main objective.

Of course, it’s possible their increased buying wasn’t caused by the pull of reciprocity. Perhaps these customers simply liked what they’d tasted so much, they bought more of it. But a closer look doesn’t support this explanation. The recipients didn’t buy more of the candy they’d sampled; they only bought more of other types of candy. Seemingly,

“Listen, if our positions were ever reversed, I know you’d do the same for me.”