WASHINGTON — Outside the handful of best-known candidates, the rest of the 2020 Democratic field risks melting together into an indistinguishable blob in the summer heat.

Candidates kept jumping into the largest presidential primary field in history because voters kept telling pollsters they wanted fresher faces and gave no one a commanding lead like the one Hillary Clinton enjoyed heading into the 2016 primary.

But former Vice President Joe Biden's stronger-than-expected start suggests voters might not have wanted so many options and may be more comfortable picking a familiar face after all.

The race is still wide open — front-runners Biden and Sen. Bernie Sanders, I-Vt., together have less than half the vote. That leaves the rest of the pack praying for a breakout moment, needing to capture the attention of increasingly distracted Americans by competing not only with one another and President Donald Trump, but also with Netflix and Candy Crush and everything else trying to monetize our time.

Democratic primary voters might be suffering what social scientists call "choice overload," which can turn much of the field into background noise.

Barry Schwartz, a psychologist who wrote the best-selling book "The Paradox of Choice: Why More Is Less," said research from the world of consumer goods shows how buyers become overwhelmed by having too many options and often gravitate toward brands they know best, glancing right over the rest.

"Instead of choosing on the basis of policies or past performance, which are hard to evaluate, people may choose on the basis of something that is easy to evaluate — like familiarity," Schwartz told NBC News. "So, yes, I'm guessing that Biden benefits from such a large field."

While Schwartz cautioned the research does not come from the world of politics, some social scientists have argued this dynamic helped explain Trump's victory in the crowded 2016 GOP field.

And it's easy to see why Democratic primary voters would be overwhelmed by a field that remains largely unknown to them.

Los Angeles Mayor Eric Garcetti, who traveled to early voting states before ultimately deciding against entering the 2020 field as a little-known underdog, said it's "just human nature to go with who we're familiar with and who we trust" — and that's Biden.

"Voting for president is like voting for a parent. You want somebody who's strong, you want somebody who you can complain to and who'll be sympathetic," Garcetti said. "I think Joe is somebody that people feel has been a part of their family. He's been in their living room on TV, he's been that uncle, as he calls himself."

That leaves lesser-known candidates working overtime to try to carve out a niche for themselves and accepting almost every interview request that comes their way to try to catch fire and stand out.

They are aware of their predicament.

When a Twitter user jokingly conflated Rep. Tim Ryan, D-Ohio, with Rep. Seth Moulton, D-Mass., two 40-something white men running underdog presidential bids, Moulton responded with self-deprecating humor.

"No Derek, this is New York City Mayor Eric Swalwell," Moulton said, intentionally mixing up New York City Mayor Bill de Blasio and Rep. Eric Swalwell, D-Calif.

No Derek, this is New York City Mayor Eric Swalwell. https://t.co/GqqH4ltUfj — Seth Moulton (@sethmoulton) May 18, 2019

Still, it can be a frustrating predicament for accomplished senators, governors, members of Congress and mayors who think they have something to offer, especially when a candidate like Pete Buttigieg, the mayor of South Bend, Indiana, has shown it is at least theoretically possible to go from being a no-name to the top of the pack virtually overnight.

Sen. Jeff Merkley, D-Ore., who also seriously considered a long-shot 2020 bid, pointed to Buttigieg and said candidates have to try to find some way to grab the attention of the political press.

"If you look back in time, there's always magical moments that the press then picks up and builds," Merkley said. "That's what the other candidates are looking for. Because they don't have the money to do big advertising now, so they have to capture the imagination of America. And to capture the imagination of America, they have to capture the imagination of the press."

"Some are trying to do it through policy ideas," he added. "Some are trying to do it by going places you wouldn't necessarily expect a Democrat to go. Some are just trying to do it by message."

But first, they'll have to justify why they want to be president in the first place, a hurdle some campaigns think their candidates are better positioned to clear than others.

Full coverage: NBCNews.com candidates page

Patrick Murray, the director of the Monmouth University Polling Institute, noted that his most recent poll showed some barely known candidates with surprisingly high unfavorability ratings.

"The field is too big. You wonder if some candidates are getting negative ratings simply as a result of voters questioning whether they really should be running," Murray said.

Other campaigns have been surprised by Biden’s surge in polls and and suggest that it's soft, driven largely by Democratic and particularly African American voters' residual good feelings for the Barack Obama era.

They hope it will run its course as other candidates make their case and as voters get exposed to some of the less flattering aspects of Biden's record. But that will require someone to go after Biden and none have shown an eagerness to do that at this point, although that could change at the first debate, which will air June 26 and 27 from Miami, sponsored by NBC.

Sen. Brian Schatz, D-Hawaii, who is watching from the sidelines as many of his friends compete with one another for a promotion, said the debates will be key for bottom-of-the-heap candidates, since it will be a rare moment that will focus voters' attention on the race and place backbenchers on the same platform as the stars.

"The debates become the moment for candidates to break out," Schatz said. "It'll be a little like Hollywood Squares ... but I just feel like voters are going to watch this thing with fresh eyes."

Still, no one really knows, he added with a laugh, recalling his unsuccessful first congressional run: "I was in a 10-person race and I didn't do well."