Honesty: The Lost Wallet Experiment

What a huge experiment across 40 countries revealed about honesty, including the surprising finding that people return wallets more often when they contain more money.

How honest are people? In a remarkable field experiment published in Science in 2019, economists Alain Cohn, Michel André Maréchal, David Tannenbaum and Christian Zünd tested honesty on a massive scale.

The experiment

Research assistants handed over 17,000 “lost” wallets to staff at public and private institutions, such as banks, hotels, post offices and police stations, in 355 cities across 40 countries. Each wallet contained a business card with an email address, allowing the owner to be contacted, and some contained money while others did not.

The surprising result

Standard economic thinking might predict that people are less likely to return a wallet containing more money, since keeping it is more tempting. The opposite happened. In most countries, wallets with money were returned more often than wallets without money. When the researchers increased the amount of money, return rates rose further.

Why?

The researchers found that people cared about two things:

Altruism: concern for the owner, who would suffer more from losing money.
Self-image: people did not want to see themselves as thieves. Keeping a wallet with money feels more like stealing than keeping an empty one.

These motives outweighed the temptation of the money.

Differences between countries

Return rates varied widely between countries, with high rates in places like Switzerland, Norway and the Netherlands and lower rates elsewhere. But the pattern of higher returns for wallets with money held in almost all countries. The variation was linked to factors like institutions and cultural values.

Why it matters

The findings suggest people are more honest than simple models of self-interest predict, and that appeals to self-image and concern for others can be powerful. This matters for designing systems that rely on honesty, such as tax compliance and trust-based transactions.

The hotel receptionist

A hotel receptionist is handed a wallet containing cash and a business card. She thinks about the owner, who might need the money for travel, and about how she would feel if she kept it. She emails the owner to collect it. Across thousands of such moments, the experiment revealed widespread honesty.

Thinking people always act in narrow self-interest

Experiments like the lost wallet study show that concern for others and self-image strongly influence behaviour, often outweighing short-term gain.

Key takeaways

A 2019 study handed over 17,000 lost wallets in 40 countries.
Wallets with money were returned more often than those without money.
Altruism and self-image explained the result.
Return rates varied by country, but the pattern held almost everywhere.