In the 1930s, a psychologist noticed that rats in a maze run faster as they near the food. It took until 2006 for anyone to prove the same thing about people and coffee.
Researchers tracked a real café's stamp-card programme, purchase by purchase. The pattern was unmistakable: the closer a customer got to their free coffee, the sooner they came back. The gap between visits shrank by around 20% across the life of the card, and cards were completed about 16% sooner than each customer's starting pace implied. The pull of a nearby reward is real, measurable, and it happens at a counter exactly like yours.
Why the pull exists at all
The mechanism is not mysterious and it is worth understanding, because it tells you where it will and will not work.
Progress is motivating in proportion to how much of it you can see. A customer with one stamp is thinking about coffee. A customer with five out of six is thinking about the sixth one, which means your shop has become the answer to a question they are already asking. The reward has stopped being a vague benefit and become a specific thing they are close to.
That last stretch also feels shorter than it is. One visit out of six left is 17% of the card, but it does not feel like 17% of the effort, because the finish is in sight. This is why the acceleration is measurable rather than theoretical: the same customer, on the same card, genuinely behaves differently at five stamps than at one.
The practical question: who is close, right now?
Here is the problem with knowing this and running a paper scheme: you cannot see who is close. The customer two stamps from a free coffee looks exactly like the customer with a blank card, and the moment of maximum motivation passes silently in a wallet.
This is why the TapReward dashboard keeps a live list called One Tap Away. It is your café's goal gradient, made visible: the exact customers sitting one stamp short, ranked by how recently they visited. A nudge sent to that list lands on people who were already leaning towards the door. In the dashboard, every nudge is then measured by one number only: how many of the people you nudged actually came back within a fortnight.
Where the effect is strong, and where it is not
Three things decide whether any of this shows up in your shop.
How often people come. A customer who visits twice a week works through a six stamp card in three weeks, and spends most of that time near the end. A customer who visits every six weeks spends most of a year on the same card and never enters the accelerating stretch at all. The effect is real in both cases and only visible in the first.
Whether the finish is in sight. A twelve stamp card for a monthly customer is not a goal, it is a filing exercise. If you cannot see the end from where you are standing, there is nothing to accelerate towards. The stamp card calculator works out what each threshold costs you, and the shape of it is usually the answer: pick the shortest card you can afford.
Whether the reward is actually wanted. Acceleration is towards something. A free item nobody particularly wants generates no pull, however close the customer gets to it, and no amount of nudging fixes a reward that is not worth the sixth visit.
Nudging without becoming noise
Knowing who is close creates the temptation to tell them, often. Four rules keep that useful.
- Only the people who are close. A message to everyone is a marketing campaign and gets read as one. A message to the nine people who are one stamp away is a reminder about something they already own, which is a different thing arriving in a different mood.
- Only the people who said yes. Nudges in TapReward go to customers who opted in, and to nobody else. There is no version of this that works by surprising people.
- Not often. Once, when it is useful. The effect you are borrowing is the customer's own motivation, and reminding them of it three times converts it into irritation.
- Measure whether they came. Not opens, not clicks. Whether the person walked back through the door inside a fortnight. It is the only number that distinguishes a nudge that worked from a nudge that was merely delivered.
Use it even if you never send a thing
Knowing who is close changes small decisions. It is the difference between "quiet Tuesday" and "quiet Tuesday, but nine regulars are one stamp off". One is weather. The other is an opportunity with names on it.
If you would rather not message anyone
You do not have to. A chalkboard by the till reading "9 regulars are one stamp away" does a version of the same job, and does it to the people already standing in your shop. It also tells a new customer that the scheme has people in it, which is a harder thing to say out loud.
The list is the asset. What you do with it is a separate decision, and doing nothing with it is still better than not having it.
The research behind TapReward is summarised in plain English at Why loyalty works. This study is not a TapReward result, and your own numbers will be your own; the dashboard exists to show them to you.
Reference: Kivetz, R., Urminsky, O. and Zheng, Y. (2006). The Goal-Gradient Hypothesis Resurrected: Purchase Acceleration, Illusionary Goal Progress, and Customer Retention. Journal of Marketing Research, 43(1).