Most people hear the word biometrics and visualize something like a retina scan at FBI headquarters.

But retail banks, too, are getting into the business of data-mapping human characteristics.

U.S. Bancorp and Wells Fargo & Co., the two largest banks in Minnesota, have both run pilot tests of voice recognition technology for smartphone banking apps and are vetting it for commercial use. Although neither would put a timetable on the projects, U.S. Bank said it could roll out voice control for mobile devices as early as next year.

Voice recognition is a logical starting point for financial institutions, the lenders say. Smartphones are already equipped with microphones and people are fairly comfortable with the technology since it's already in use on some smartphones and car navigation systems, for instance.

Amazon has been using a crazed Gary Busey to market its Fire TV, a small box that allows high-definition televisions to access Internet programming. Fire TV's remote control uses voice recognition so people can talk to it to find shows and games.

"The voice is such an easy and natural way to interact with things," said Wells Fargo Senior Vice President Brian Pearce, head of retail mobile channel and digital innovation for Wells Fargo. "Customers are asking for it and thinking about it."

Pearce said that the ability to search banking transactions worked particularly well in Wells Fargo's pilot. For instance, people could say: "Tell me how much money I spent at Dillard's last month," and get the total. They could follow with "What about the month before?" and the program could remember the previous query and run a new one.

"There's no way we could put that many drop-downs in the interface," Pearce said.

U.S. Bank said its three-month pilot focused on voice recognition for authentication. It modified its mobile banking app so that users could register their voice itself as a password, avoiding the task of creating and memorizing increasingly unique and complicated passwords.

To Dominic Venturo, chief innovation officer for U.S. Bank Payments Services, the big plus is security. Voice prints, he said, "are terribly unique."

Yes, a bad cold or loud background noise can render it less effective, but it doesn't become easier to copy, he said.

The test results exceeded his expectations, Venturo said, and the bank is exploring other ways to use voice control, such as in call centers or to wire money. It's tapping voice technology company Nuance Communication Inc. of Bur­lington, Mass.

There are a handful of financial institutions that have at least publicly stated they have tested voice, Venturo said. Other biometric approaches to authentication, such as palm vein readers or retina scanners, are highly reliable but can be unwieldy, expensive and there can be a creep factor, he said.

Mark Schwanhausser, director of Omnichannel Financial Services at Javelin Strategy & Research, calls the potential for voice recognition in banking huge.

"That is potentially a Holy Grail-type customer service," he said. "Is it going to happen tomorrow? Absolutely not."

In terms of the public's comfort with biometrics for authentication in mobile banking, Javelin research shows that fingerprinting is the leader at the moment, with voice second, he said. Apple, he noted, has fingerprint identity sensors on its iPhone 5s. So does the Samsung Galaxy S5.

"Biometrics is only in the first turn of the Belmont Stakes," Schwanhausser said. "Anything could happen."

Jennifer Bjorhus • 612-673-4683