Reciprocity decay: How our desire to give back wanes over time

“You scratch my back, and I’ll scratch yours.” The traditional saying remains true even in modern society, and we’d like to think that when we perform a favor for someone else, they will return it in the future. But this is not always the case. Research shows that reciprocity has a very narrow window, and our desire to give back wanes rapidly before disappearing altogether.

About three weeks ago, I met a friend for coffee. When she had to rush off, I happily covered our bill and assumed that next time, she would do the same. However, “reciprocity decay” forewarns me that, as three weeks have already passed, I should probably forget about that coffee ever being repaid. Understanding reciprocity decay can provide us with valuable insight into both our expectations of others and the way we collaborate with them.

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The science of reciprocity

Reciprocity is a deeply rooted dynamic of human relationships. Reciprocity of both benefit-for-benefit as well as harm-for-harm was a cornerstone of relationships in ancient Greece. Extensive research has shown that the principle of “voluntary requital” was a form of transaction in a time when there was no formal system of trade.

There is some evidence demonstrating that it’s not only humans who are capable of reciprocity. Rats have been shown to set up “food-exchange programs”, vampire bats partake in high levels of reciprocal grooming, and capuchin monkeys show reciprocal provision of food from food-rich to food-poor environments. These mechanisms enhance survival of the species.

In recent years, cultural anthropologists have discovered that human relationships are based on a “web of indebtedness”. American researchers reported that reciprocity can include rewarding kind actions or punishing unkind actions. Researchers from the University of Zurich noted that reciprocity has powerful implications for economic domains. They found that reciprocal behavior can determine both the enforcement of contracts and social norms, as well as greatly enhancing collective action.

Through reciprocity, sophisticated systems of aid and trade have become possible, bringing immense benefits to societies that utilize them. In professional circumstances, employees may work above and beyond their role to provide additional services, if they believe that they may later be reimbursed with praise, promotion, a pay rise or another benefit.

In one’s personal life, reciprocity can be linked to the frequent exchange of favors between family or friends, the existence of customer loyalty, and the tradition of tipping in restaurants.

Writing with Benedikt Herrmann, Simon Gächter summarized that the human web of indebtedness created through direct and indirect reciprocity is crucial to successful human cooperation.

The impact of reciprocity decay

As we’ve seen, reciprocity is essential for a modern society that functions well, and many of us are happy to give when we feel confident that, in the future, we will receive something in return. However, studies by Amanda Chuan, Judd Kessler and Katherine Milkman suggest that if reciprocity is not triggered within a specific timeframe, any sense of obligation can vanish, leaving the initial donor with nothing at all.

The researchers examined data from a university hospital that had sent more than 18,000 donation requests to patients following hospital care. Patients were most likely to donate if the request was sent within 30 days of their visit, with a significant decline when it was sent between one and four months later.

They concluded that economic behavior is time sensitive due to reciprocity decay. It is therefore important to capitalize on opportunities to receive payment for any “debt” promptly, rather than leaving it too long to ask.

Reciprocity decay is likely due to the memory of a generous act fading in time. Something that was significant initially may not feel as valuable one week later.

My friend who was grateful to avoid having to wait for the bill may now be consumed by a busy work schedule or a mountain of life admin. While making it to a meeting on time was important three weeks ago, this may no longer hold any significance. Furthermore, in the normal chaos of life, she may simply have forgotten about the bill.

Older research agreed that reciprocal decay was likely due to the fading memory of a favor. However, this study also highlighted that the sense of obligation to repay a favor is likely to depend on how valuable the initial favor was. One coffee is of little consequence, whereas saving someone else’s life could “produce a sense of obligation that lasts a lifetime.”

Fostering balanced cooperation

By taking reciprocity decay into account, it’s possible to foster more balanced cooperation. When someone is indebted to you, avoid waiting too long to make a request for reciprocal action. If the repayment of a coffee had been very important to me, I could have messaged my friend the following day to arrange another catch up.

Similarly, if you want customers to provide feedback on your service, make sure your request is timely. Asking for immediate feedback can be off-putting, while waiting too long may reduce your chance of a response. It is therefore advisable to wait a day or two before exploring reciprocity.

Conversely, if you recognize that you have waited a long time for a favor to be repaid, make sure the first correspondence you send triggers the recipient’s recall of your past act of kindness. If you helped a colleague plan a workplace event, you can spark fond memories by gently reminding them of how enjoyable the day was. This may make them feel more inclined to help you out in return, despite the delay.

Although in some cases, an equally weighted favor might be returned despite time passing, you will often need to accommodate for reciprocity decay. While hospital patients may be less likely to make financial donations many months after treatment, they may be willing to share a link to the hospital’s charitable causes on their social media instead.

Finally, it’s important to recognize when you have missed the boat. If a long time has passed, draw a line in the sand and accept that a favor won’t be repaid once an individual no longer feels indebted.

This may help to minimize any sense of disappointment you may feel around the favor you provided. For instance, buying a coffee for a friend is no big deal. Rather than feeling I have been fleeced or that my minor generosity went unnoticed, it’s better to forget it altogether.

Reciprocity is an ancient phenomenon that is essential for the healthy functioning of society. Although we expect others to remember our kind deeds and repay them, as time passes it is likely that reciprocity decay will occur.

Fortunately, we can foster more balanced cooperation by not waiting too long to request that a favor is repaid, making allowances for the other party when some time has passed, and knowing when to accept that it is time to simply let go.


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