Germany and Austria are neighbors with similar cultures. But only about 12 percent of Germans agreed to be organ donors, while over 99 percent of Austrians did.

Why? In Germany, you must say "yes" to become a donor. In Austria, you are a donor unless you say "no." Most people in both countries did nothing. This shows the power of the default, the choice that is already made for you.

Why do over 99 percent of Austrians agree to organ donation, while only about 12 percent of Germans do? According to a 2003 study by Eric Johnson and Daniel Goldstein, the answer is the default setting. Austria uses an opt-out system, so people are donors unless they refuse. Germany uses an opt-in system, so people must actively sign up.

In both countries, most people simply did nothing. Defaults are powerful because changing them takes effort, because they look like a recommendation, and because giving up the current option can feel like a loss. The same idea works with money. When one American company automatically enrolled new workers in a retirement savings plan, participation rose from about 40 percent to over 80 percent.

Germany and Austria share a language and much of their culture, yet only about 12 percent of Germans consent to organ donation, against more than 99 percent of Austrians. In a 2003 paper in Science, Eric Johnson and Daniel Goldstein traced the gap to the default rather than to national character. Austria presumes consent unless citizens opt out. Germany requires them to opt in.

Across Europe, opt-out countries showed consent rates above 85 percent, and an online experiment found that changing nothing but the default answer to a question shifted responses substantially. Three forces seem to be at work: the effort needed to change a choice, the sense that the preselected option is being recommended, and loss aversion, which turns the default into a reference point.

A 2019 meta-analysis found that default effects are real overall but vary a great deal from one domain to another. A high consent rate also does not guarantee more transplants. Actual donations depend on hospital systems and family wishes, and a 2019 comparison of 35 countries found no significant difference in deceased donation rates between opt-out and opt-in systems. Online shops that pre-tick paid options show how defaults can also be used manipulatively.