Researchers "Lost" 17,000 Wallets Around the World. The More Money Inside, the More Often They Came Back

Imagine you work at the front desk of a hotel. A stranger walks in, puts a small wallet on the counter and says they found it on the street around the corner. They are in a hurry, they explain, so could you take care of it? Then they leave.

Inside the wallet you find a business card with a name and email address, a short shopping list, a key and, in some cases, a modest amount of cash. What do you do?

Between 2013 and 2016, versions of that scene played out more than 17,000 times in 355 cities across 40 countries. The "strangers" were research assistants. The wallets were part of one of the largest experiments ever carried out on everyday honesty. Its findings, published in the journal Science in 2019 by Alain Cohn, Michel André Maréchal, David Tannenbaum and Christian Lukas Zünd, overturned a prediction that many experts considered obvious.

How the experiment worked

The researchers chose places where handing in a found wallet would feel natural: banks, hotels, post offices, museums, police stations and similar public institutions. Each wallet was a transparent business-card case, so the contents were visible without opening anything. The business card belonged to a fictional person, with an email address the researchers monitored.

The key variable was money. Some wallets contained no cash. Others contained the equivalent of 13.45 US dollars in the local currency, a small but meaningful sum. The question was simple: would the person who received the wallet email the owner to return it?

Before revealing the results, it is worth making a prediction yourself. Most people, including professional economists, assume that more money creates more temptation. A wallet with no cash is easy to return. A wallet with cash in it invites someone to quietly pocket the money.

The surprising result

Across the whole study, wallets containing money were returned more often than wallets without it. Without cash, around 40 percent were reported to the owner. With cash, the figure rose to around 51 percent. The same pattern held in the vast majority of countries studied.

The researchers then pushed further. In three countries, the United States, the United Kingdom and Poland, they ran an additional version of the experiment with a much larger amount, roughly 94 dollars. If temptation drove behaviour, this should have been the point where honesty collapsed. Instead, return rates went up again, to around 72 percent.

The research team also surveyed both the public and a group of economists, asking them to predict the outcome. Most predicted that more money would mean fewer returned wallets. The real world did the opposite.

Why would more money mean more honesty?

The researchers proposed two main explanations, and they designed parts of the study to test them.

The first is altruism. A wallet with money in it represents a bigger loss for the owner. Someone who imagines the owner's worry may feel a stronger pull to return it. To test this, the researchers ran a version of the experiment with and without the key. A key has no value to the finder, but it matters to the owner. Wallets with a key were returned more often than those without, which suggests that concern for the owner plays a real role.

The second explanation is self-image. Most people want to see themselves as honest. Keeping a wallet with nothing in it feels like a small lapse. Keeping one full of cash starts to feel like theft. The more money involved, the harder it becomes to tell yourself a comfortable story about what you did. In other words, the cost of keeping the money isn't only financial. It is the cost of becoming, in your own eyes, a thief.

When the researchers surveyed people about how keeping wallets with different amounts would feel, the answers fitted this idea. Pocketing a larger sum was rated as more like stealing, and more damaging to how people would see themselves.

Differences between countries

Return rates varied considerably from country to country. Places such as Switzerland and Norway had some of the highest rates, with large majorities of wallets returned. Others were much lower. The researchers found that higher return rates tended to go together with factors such as stronger institutions and certain cultural values, though they were careful not to claim that any single cause explained the gaps.

It is important to read these comparisons cautiously. The experiment measured one specific kind of behaviour, by employees in particular kinds of workplaces, in particular cities. Local practices, such as how lost property is normally handled or how comfortable staff feel emailing a stranger, could all affect the numbers. What stands out more than the differences is the consistency of the main finding: in almost every country, money made people more honest, not less.

Other wallet experiments

The idea of dropping wallets to test honesty is not new. Magazines and newspapers have run informal versions for years, scattering wallets on city streets and recording how many come back. These stunts are entertaining but usually too small to support firm conclusions. The value of the Science study was its scale and careful design: thousands of wallets, standardised contents and a clear measure of what counted as a return.

The study is also a useful reminder of how often our assumptions about human nature are wrong. Economists have long worked with models that treat people as primarily self-interested. The wallet experiment does not show that people are saints. Most of the wallets without money were never reported, after all. But it shows that honesty is not simply a calculation of what you can get away with.

What this means in everyday life

There are practical lessons here, for individuals and for organisations.

People care about how they see themselves. Systems that remind people of their own values, or make it clear when an action would cross a line, can be more effective than systems that rely only on surveillance and punishment.

Make it easy to do the right thing. The wallets in the experiment included an email address. Returning them was simple. In real life, honesty often fails not because people want to cheat, but because doing the right thing is complicated. Clear lost-property systems, easy ways to report mistakes and simple procedures for returning things help more people act on their good intentions.

Don't assume the worst. A cynical view of others can become a self-fulfilling prophecy, shaping rules, policies and personal behaviour in ways that treat everyone as a potential thief. The evidence suggests that most people, most of the time, are more honest than we expect.

The quiet power of a key

Perhaps the most touching detail of the study is the key. It had no value to the person who found it. Nobody could sell it or spend it. Yet its presence made people more likely to reach out to a stranger they would never meet. Somewhere, they seemed to think, someone can't get into their home tonight.

That small act of imagination, putting yourself in the place of the person who lost something, may be the real heart of honesty. Not fear of being caught, and not a careful weighing of costs and benefits, but the simple recognition that there is a person on the other side of every lost wallet.