18,515 patients who had been admitted to a university hospital were subsequently mailed a request to donate to the hospital charity.

The researchers found that requests delayed by about 30 days after each patient’s visit reduced the donation rate by 30%, falling ever further as the delay increased.

Timing is everything.

‍There is a ‘goldilocks’ window of time within which kind acts will most likely be reciprocated:

• Not too quick: diners asked to review their experience when paying the bill should instead be prompted the next day and not at the table.
‍
• And not too slow: try recalling a meal you had 3 months ago…

A small delay? Ask for less.

‍If you've waited too long for a reciprocal favor in return, make it easier. Provide a subtle reference to your past act of kindness, but instead of asking for a donation, ask for a share, perhaps combining with a Reward.

A large delay? Start afresh.

‍Life goes on and we quickly forget others' kindness, so for extreme delays, expect no response.

Instead, create a Fresh Start with an easy re-entry to reciprocity: a new seasonal menu tasting invite for a restaurant, for instance. After the event, follow up with your request. It will likely be granted, such is our internal desire to rebalance things.