NEW YORK (KGO) -- Wallets containing money are far more likely to be returned, according to a new global study.
Researchers with the University of Michigan and the University of Zurich planted more than 17,000 "lost wallets" throughout 355 cities in 40 countries, sending a team of research assistants dressed as locals to return the wallets at nearby establishments, including banks, theaters, museums, post offices, hotels and police stations.
Each wallet, a clear business card case, was filled with three business cards containing the name, email and address of the supposed owner. The owner was made to look like a local who worked or lived in the area. Researchers then tracked whether employees in each business given a wallet would actually return it to the rightful owner.
Surprisingly, the presence of money in the wallet had a drastic effect on return rates. Wallets containing money were more likely to be returned, and the more cash the better.
On average, 40 percent of people returned a wallet with no money. That number jumped to 51 percent when the wallet contained the equivalent of $13 in local currency. When researchers added $94 to the wallets, 72 percent of people made a return.
Social scientists argue that people don't like to see themselves as thieves, and when a wallet contains money, especially a significant amount, a person is forced to question their own character and sense of morality.
The trend showed up in every nation, although the actual numbers varied.
Switzerland led the study with a 79 percent return rate for wallets with cash. The United States fell in the middle with a 57 percent return rate, while China had the lowest return rate of all the countries studied, at just 22 percent.
Some critics say a real-world scenario involving wallets on a sidewalk may yield different results, as employees at their place of work are more likely to make the ethical choice.
Overall, professors at Duke University and the University of Massachusetts say the results fit with previous studies on dishonesty and supports the idea that people care about each other, and about being honest.