There are 179 actresses who are better known than Maya Rudolph, including Whoopi Goldberg (third most famous), Lindsay Lohan (15th) and Gwyneth Paltrow (32nd). But Ms. Rudolph is more likable than those three and many others who are household names, according to the market research firm YouGov.

So it made sense that M&M’s, the candy that has found itself in the cultural cross hairs, would enlist Ms. Rudolph as its corporate pitch-woman and make her the star of a commercial scheduled to air during Super Bowl LVII on Sunday.

Nearly 75 percent of the people who have heard of Ms. Rudolph said they liked her, and her popularity was on an upswing in the fourth quarter of 2022, YouGov reported in its most recent ranking. Ms. Goldberg and Ms. Paltrow each came in around 55 percent, and Ms. Lohan at 39 percent.

Ms. Rudolph, a “Saturday Night Live” cast member from 2000 to 2007, is likable enough to make the multibillionaire she plays seem down to earth on the AppleTV+ series “Loot.” She managed something similar more than a decade ago in “Bridesmaids,” winning over audiences as a bride-to-be who develops bride-zilla tendencies. Now she will attempt to do the same for a candy brand in trouble.

M&M’s got some blowback from cable pundits and social media warriors after it made cosmetic changes to its long-running cartoon characters. The Fox News host Tucker Carlson and others accused the brand of “woke” advertising, arguing that the “spokescandies” had lost their sex appeal. A point of contention was that one of the cartoon candies had replaced her high-heeled go-go boots with sneakers — and at times it was hard to tell if M&M’s was trolling right-wing commentators with its promotional stunts or if it was the other way around.

“M&M’s will not be satisfied until every last cartoon character is deeply unappealing and totally androgynous,” Mr. Carlson said on his show more than a year ago. He was at it again last month, saying, “The green M&M got her boots back but apparently is now a lesbian, maybe, and there is also a plus-sized obese purple M&M.”

In the commercial to be shown during the second quarter of Sunday’s game, Ms. Rudolph will try to calm the brouhaha. (A spokeswoman for M&M’s “Chief of Fun” declined to comment for this article.)

Marketers, especially those trying to create an appealing image for unlikable industries like pharmaceuticals and airlines, know that a bit of charm can do a lot to disarm doubters and critics. In addition to Ms. Rudolph, other “Saturday Night Live” alumni have brought some warmth to companies that could certainly use it. Amy Poehler, whose affability set the tone for the sweetly humorous sitcom “Parks and Recreation,” has taken on the challenge of making a cable, internet and phone company seem sympathetic in a series of commercials for Xfinity. Cecily Strong, who left “Saturday Night Live” in December after a 10-year run, has lent her services to Verizon.

Rashida Jones, a onetime regular on “Parks and Recreation” and “The Office,” manages to make banking seem almost fun in commercials for Citi. Jennifer Coolidge, an endearingly kooky addition to the America’s Sweetheart club thanks to her performance on “The White Lotus,” was featured in two Super Bowl commercials last year: one for Uber Eats, which had faced criticism for its treatment of pandemic-shocked restaurants and gig workers, and another for FanDuel, part of a growing sports betting industry that has drawn worries about gambling addiction.

But companies can sometimes make a misstep in their attempts to capitalize on the amiability of certain celebrities. In 1984, Burger King introduced “Mr. Rodney,” a character based on Fred Rogers, the esteemed host of the PBS children’s show “Mr. Rogers’ Neighborhood.” Wearing a cardigan, Mr. Rodney addressed the camera in a gentle voice: “Hi, neighbors. Today’s new word is something McDonald’s does to every burger: Let’s call it ‘McFrying.’ Can you say that?”

One call from the real Mr. Rogers got the commercial bounced from the airwaves. “Mr. Rogers is one guy you don’t want to mess with, as beloved as he is,” an apologetic Burger King spokesman said at the time.

Beer companies may not need the assistance of likable celebrities as much as banks and phone companies, but Anheuser-Busch InBev is taking no chances on Sunday, with several Super Bowl commercials, including one starring Serena Williams.

Likability “is paramount” in the choices of corporate spokespeople, said Shana Barry, the head of celebrity, entertainment and influencers at Anheuser-Busch. “You want to associate with a talent that is having a good time,” she said. “We want to make sure that you’re paying attention to the ads and that you can connect with them onscreen.”

Social scientists who have delved into the mysteries of likability point to the mere exposure effect (sometimes known as the familiarity principle), which posits that people tend to like something the more they are exposed to it. They also cite emotional contagion, a phenomenon in which people often sync up with the emotional state of others in their orbit, meaning that viewers may get a lift when they see someone having a good time in a TV commercial. And a 2021 academic study found that experts who testify in civil and criminal trials have an easier time persuading jurors if they are perceived as likable.

“The essential elements are true no matter who you are,” said Natalie Anne Kerr, a psychology professor at James Madison University. “Companies can manipulate the situation to promote liking and connection to their ambassadors, especially if they’re actors who can intentionally choose to play the role of a likable person.”

But being seen as trying too hard to be liked can backfire, Dr. Kerr said. Truly likable people show vulnerability (this is known as the pratfall effect) and are relatable (the similarity attraction effect). See Keanu Reeves, who appeared in a 2018 Super Bowl commercial for Squarespace, doing a motorcycle stunt while reciting the words of the 1983 cult hit “Adventures in Success” as the track played in the background. Quirkiness may also be an asset, Dr. Kerr added, noting that one of her favorites actors is Nick Offerman, who is known for playing gruff but kind loners, as well as for his good-natured appreciation of carpentry and his wife.

Tone deafness can destroy likability, said Mitch Prinstein, a psychology and neuroscience professor at the University of North Carolina and the chief science officer at the American Psychological Association.

“We always tell elementary school kids that they can’t walk up to a bunch of kids playing Legos and say, ‘That’s stupid; let’s play with trucks,’” said Dr. Prinstein, the author of “Popular.” “You can include your truck with the Legos, but you can’t just disregard the group norm.

“The same thing applies to adults,” he continued, “whether you’re leading a boardroom or you’re a celebrity. You have to read the room.”

Public figures may have a tougher time connecting with audiences when they become so famous and wealthy that they lose touch with everyday experiences, he added. An out-of-touch star is rarely likable, especially at a time when fans have grown accustomed to joining their favorite entertainers on social media as they document a date night or grocery run.

Rather than relying on big stars to pitch products, some companies are tapping TikTok tastemakers and Instagram nanoinfluencers to chase niche groups. “Brands are really looking for authenticity, for somebody that can talk about the brand in a way that others might not be able to,” said Adma Ortega, who handles celebrity and influencer relations for the Wieden & Kennedy ad agency in New York. “They want to talk to a specific audience, because you can’t talk to everyone anymore.”

Some companies break through the noise by ignoring likability altogether, as Samsung did in building ads around the reality TV star Christine Quinn, who once said of her role on “Selling Sunset”: “I love being the villain and I wouldn’t have it any other way.”

Deciding on a spokesperson is increasingly complicated, involving metrics like social media follower counts, audience demographics, algorithmic calculations including the Klear Score, the Aspire authenticity score and E-Score polls. After the Super Bowl, Anheuser-Busch and other companies will study rankings like Ad Meter and the Super Clios to see how viewers reacted to their commercials.

Some firms still use the Q Score, a nearly 60-year-old measure of appeal that costs $1,750 per name. Clients get a detailed breakdown of sentiment among different demographics, and can also buy a full work-up of more than 1,200 personalities or a ranking of celebrities customized by their appeal to a particular audience. The score is used by ad agencies, movie studios, TV networks, lawyers and estates, said Steven Levitt, the president of the Q Scores Company.

The “Q” stands for “quotient” — a reference to how the rating is calculated, by dividing the percentage of respondents who say a celebrity is one of their favorite personalities by the percentage of those who have heard of the person. Another part of the rating evaluates unpopularity. The highest score ever, a 71 in 1985, went to Bill Cosby; nowadays, celebrities rarely score above the low 40s, Mr. Levitt said. Ms. Rudolph’s score is 19, three points above the average for actresses, he said.

Ad makers often ignore Q Scores in favor of gut instinct, Mr. Levitt added. “A lot of decisions are not based on data,” he said. “They’re based on creative appeal, or the strength of an executive to outshoot and overpower subordinates and say, ‘No, I think this is the way to go.’”

But celebrity likability may not last. It only takes one slap at the Oscars, one rude complaint about an omelet, or one too many reports that a nice talk show host with a penchant for dancing was perhaps not so nice after all.

Which may be why some of the most popular Super Bowl commercials of recent years have had no recognizable celebrities front and center, according to an analysis by the measurement firm iSpot.TV. Last year, the most likable ad featured a variety of wild animals grooving to the 1987 Salt-N-Pepa hit “Push It” after sampling some Flamin’ Hot Doritos.

And the stars of the most likable spot on record, a Budweiser commercial from 2014? Clydesdale horses and a golden retriever puppy.