The document discusses a field experiment comparing response rates for a mail survey when offering a $50 payment upon completion versus including a $5 payment. The survey with the $50 promise received a 23% response rate, while the version with the $5 inclusion received 49%. It notes that people feel more obligated to reciprocate when given an actual gift rather than an empty promise. The document encourages applying this lesson by considering giving customers a small gift within a week and sharing results.