Sam Wang is professor of molecular biology and neuroscience at Princeton University, where he operates the Princeton Election Consortium.

Voters (and one non-voter) in Maryland’s 2016 primary election. (Photo by Evelyn Hockstein/For The Washington Post)

West Virginia is starting an experiment that may fundamentally alter how Americans vote. By implementing a policy with the innocuous name of “automatic voter registration,” the state is using modern behavioral science to make it easier for residents to be good citizens.

Here’s how automatic voter registration works: Instead of having to affirmatively sign up to vote, eligible citizens would be automatically and securely registered to vote when obtaining or renewing a driver’s license, or when interacting with other government agencies. They can choose to opt out — but they have to make an active choice not to register. Most states now have an opt-in system, where it’s up to citizens to register if they want to be able to vote. Automatic registration changes the default — you will be registered to vote, unless you ask not to be.

To a behavioral scientist, though, requiring people to register to vote in advance seems like an obvious way to deter them from turning out. Registering before an election may not sound difficult in theory, but psychology suggests otherwise. Our brains are good at seeing the cost of acting now — but not so good at weighing a benefit that is months or years away. And in states where advance registration is required, voting relies on being able to imagine what one might want to do on the first Tuesday of November, as far as two years off.

Such advance planning requires executive function, the brain’s ability to plan and execute. If this morning for breakfast, you chose a pastry instead of fruit that would be better for you in the long term, you chose your immediate pleasure over a long-term health benefit. This ability depends on the prefrontal cortex. Behavioral scientists look for ways to help your prefrontal cortex make better choices when faced with such a trade-off. Opt-out approaches overcome the brain’s inertia. In an opt-out system, if you do nothing — which most folks specialize in — then you are registered.

It would be hard to come up with a better place to try an opt-out experiment than West Virginia. Only 46 percent of West Virginians who were eligible to vote in 2012 exercised their right. Only three other states — Hawaii, Oklahoma, and Texas — shared the dubious honor of falling below 50 percent. All four states share a common feature: voters must register 21 to 30 days in advance of an election.

How many more people would vote if they were automatically registered in advance? Although automatic voter registration has not been around long enough to give a direct answer, we can get some idea from another policy that takes a load off the prefrontal cortex: same-day registration, which allows citizens to register on Election Day and cast a ballot.

Eleven states and the District of Columbia allow Election Day registration. In 2012, all 12 jurisdictions saw voter turnout above the national average — 66.4 percent compared to 58.6 percent nationwide. Of the top four voter turnout states, three have same-day registration. Same-day registration crosses party lines: of the 11 states that had same-day registration in 2012, legislative control at the time was Republican in seven states, Democratic in two states, and split-party in two states. On average, same-day registration is associated with 5 to 7 percent higher voter turnout. This is what happens when we allow folks to register in a way that requires no preplanning.

Automatic voter registration may help even more: Only 76 percent of eligible Americans are even registered to vote. A handful of states are making the switch to automatic voter registration: California, Oregon, Vermont, and Connecticut. We do not yet know how much turnout will increase in these states, but in Oregon, the rate of new registrations has quadrupled after just a few months under the new system, according to an analysis from the Brennan Center for Justice.

How high might the rate of registration go? Based on similarly designed interventions, it is near certain that changing the “default option” will substantially increase the number of registered voters. This arises from the principle that if you do nothing —which is what most people specialize in — then you’re registered in an opt-out system.

A 2001 study looked at a large U.S. corporation that began automatically enrolling its employees in a 401(k) savings plan. When employees had to opt into the plan, 35 percent were not enrolled even after three years. But among those who had opt-out automatic enrollment, non-participation dropped to 2 percent. Evidently, when your company makes it easy for you to save, taking the plunge is far easier.

The power of the default option can even save lives. In some European countries, you are an organ donor unless you opt out. These countries see a 6 percent rate of people who decline to be donors, compared to 86 percent in countries where you opt in to the program.

In these two examples, compliance rates are 94 to 98 percent. If we assume a 94 percent registration rate is achievable, and 76 percent are currently on the rolls, this would mean close to 40 million more voters registered across the country. We don’t know the exact number of new registrants who will actually end up voting, but it should exceed the benefit from same-day registration because it removes even the little effort that is involved to actively register.

Automatic voter registration may sound unromantic to activists who get excited about shoe-leather approaches. As emotionally appealing as it may be to knock on doors and drag supporters to the polls, get-out-the-vote efforts will move the needle just a fraction, typically only a few percentage points. Automatic voter registration has the potential to surpass that amount considerably. The idea is not only common sense, but it fits well with what we know about how the brain plans ahead — but often doesn’t.