How do restaurants lure back diners—and boost business—after long months of shutdowns and mandates?

Researchers may have some answers.

Academics have spent years poring through the restaurant industry and figuring out what strategies do and don’t work to attract diners and get them to spend more—and now they are seeing ways that businesses...

How do restaurants lure back diners—and boost business—after long months of shutdowns and mandates?

Researchers may have some answers.

Academics have spent years poring through the restaurant industry and figuring out what strategies do and don’t work to attract diners and get them to spend more—and now they are seeing ways that businesses can apply those lessons to the post-Covid world.

Here’s what they have found.

Split the dining rooms

“There are two types of diners right now. One is often younger people who want to overcompensate for everything they missed out on,” says Dipayan Biswas, professor of marketing at the University of South Florida’s Muma College of Business. This crowd is often looking to socialize with people in an intimate space with loud music and dim lights, he says. The other group is more fearful of the virus—and apprehensive about returning to indoor spaces—but can be reeled back with safety and precautions.

How can restaurants meet the needs of both? Prof. Biswas recommends creating two different atmospheres if possible—akin to the smoking and nonsmoking sections of yore. One section might have tables more spread out, brighter lights and quieter music to reassure diners and give them as much space—and sense of safety—as possible. The other area would be more dense, darker and louder, for diners who don’t mind getting up close and personal.

Divide the space

When restaurants do set up socially distanced spaces indoors, whether voluntarily or by mandate, they must make sure to use that space wisely. Pre-Covid-19, many restaurants were all about getting as many diners through the door as possible—and maxing out seating to do so. But during the height of the pandemic restrictions, when restaurants were forced to reduce capacity, many simply removed tables from the dining room.

That was a missed opportunity, says Stephani Robson, a senior lecturer emeritus at Cornell University’s School of Hotel Administration. Instead of leaving the space empty to accommodate social distancing, she recommends filling it with furniture that creates more of the anchored seating that diners prefer in restaurants.

“A diner’s spend per minute goes up when they feel anchored,” Prof. Robson says. “They like to sit up against walls or windows or a structural column.”

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She says this deep behavioral wiring probably has to do with humans being very front-focused compared with hunting or prey animals. “We don’t have eyes in the back of our head and we have relatively poor peripheral vision, so we like our back and even our sides against something,” she says.

That doesn’t mean renovations and remodeling. Prof. Robson says restaurants can create the sensation of being anchored and having a private space by adding a simple bookcase or a planter that can be easily moved. They create more of the desirable anchored seating, and they serve cautious post-Covid diners looking for a little more social distancing from other tables. And her studies found that the perception of distance is more important than the actual inches—diners in booths rated the tables as well spaced, and those at open tables said seating was too close.

“The actual distance isn’t the issue,” she says. “Give me something physical that helps me control my space, it makes me feel more comfortable.”

Don’t remind people of bad times

Prof. Robson also warns against the hygiene theater that many restaurants and shops indulged in during the height of the pandemic.

“Don’t have hand sanitizer at the tables. It sends the message that dining out is not that safe and it constantly makes the pandemic top of mind—and this is counter to the reason they are going out,” she says. “A discreet dispenser by the door is fine, but that’s it. You want to send the message to diners that once you pass through our portal, you are in a safe place.”

Different fragrances signal different characteristics about an environment.

Illustration: Martin Tognola

Spread pleasing scents

Research shows that sensory cues can be used to enhance the perception of space and cleanliness. Many restaurants and retail settings have been experimenting with the practice for years, but it could be even more crucial and effective with post-pandemic consumers. For example, different fragrances signal different characteristics about an environment. Cooling scents—such as eucalyptus, menthol or peppermint—are perceived to be “clean” scents—think spas or breath mints.

Using cooling sensory elements has additional advantages for restaurants. Evolution has taught our bodies that when we feel cold, we compensate by trying to get more fat. Cooling scents therefore send a signal to the brain, prompting people to eat more and drink more alcohol—as alcohol has a warming effect, and the process of eating generates body heat, says Prof. Biswas.

Restaurants can go as basic as using a strategically placed nebulizer or diffuser or two, while larger establishments often have the option of atomizing fragrances through their venting system.

(Be warned, though, that some scents may be bad for business. According to Prof. Biswas, research shows that warmer scents like sandalwood, cinnamon and cedarwood also cause a chemical sensory reaction—giving diners the perception that a place, and their body, are warmer, and they tend to eat less.)

Music and ambience affect the appetite

Sight and sound also shape a diner’s perception of food even before it reaches the fork or spoon.

Using mirrors and brighter lights, for instance, can make a section appear more spacious. Conversely, dimmer lighting and louder music serve diners looking for closer interactions, which often leads to more spending. Once again, our bodies react physiologically to sensory changes—when the lights go down, our melatonin production goes up. This numbs the body’s senses and inhibitions.

Prof. Biswas found that in dimly lit scenarios, patrons are more apt to order dessert or another glass of wine than in a brightly lit room. “Dim light gives us a perceived sense of anonymity. Moral transgressions go up in dimly lit situations,” he says. “With bright lights, your alertness level is higher and people act in a more moral way.”

In his study conducted at locations of a national restaurant chain, the differences were stark. In brighter environments, 52% of diners ordered healthy options compared with just 35% in more dimly lit scenarios. When it came to counting calories, customers in dim ambient lighting ordered 39% more calories than those in bright.

The results were similar when his team tested music played at different volumes in restaurants. “When loud music is playing, people order more fried foods and more high-calorie, unhealthy foods,” he says. “On low-volume-music days, people ordered more salads.”

Charles Spence, a professor of experimental psychology at the University of Oxford and head of the Crossmodal Research Laboratory, has been studying how atmospherics can affect the perception of taste.

“Loud music makes people eat and drink faster, and it makes salty and sweet harder to taste,” he says. Some restaurants capitalize on the phenomenon by turning the decibels up during the busy times to turn more tables faster, and down during periods they want to let diners linger. Turning the volume up has also been shown to amplify diners’ perception of the savoriness of umami strong foods like tomatoes, soy and MSG.

“Loud music is very umami forward,” Prof. Spence says.

Classical music, on the other hand, has been found to increase wine sales in stores and fine-dining restaurants. Prof. Spence’s studies found that with the proper pairing of classical music, consumers said they enjoyed the wine 11% over the same wine savored in silence. “There is such a strong association between classical music and class and quality,” he says. “When you hear that music, consumers are primed to be willing to spend more.”

In brighter environments, people tend to order healthier foods.

Illustration: Martin Tognola

The takeout experience

While it is easy to change the soundtrack for the dining-in experience, the pandemic has pushed a large portion of restaurant sales to takeout. Could curated music and playlist links included with an order enhance diners’ perception and experience with takeout meals eaten at home too? Research says yes.

Prof. Spence’s study found that people listening to jazz, for instance, perceived the meal as more expensive than the same meal paired with pop music. And pairing Pavarotti with Italian food made consumers rate the dishes higher.

Some restaurants and national brands are including links to curated playlists to be enjoyed alongside their food and drinks at home. “Optimizing the sonic backdrop when the consumer tastes their products really can make all the difference,” Prof. Spence says.

White plates can be more attractive to diners than red ones.

Illustration: Martin Tognola

Color me hungry

Prof. Spence wanted to test if the color of the plate or glass influences diners’ perception of the taste they actually experience. To find out, he and his team served identical strawberry mousses on white and black plates. Diners deemed the dessert served on white plates as higher in sweetness, flavor intensity and quality. Studies have also shown that people eat more when food is served on a white plate as opposed to red, as Prof. Spence says red “triggers an avoidance motivation.”

Color can also affect how much a diner tips, research shows. “Most people think tipping is related to service quality, but there is actually a very weak link between tipping and service quality,” says Na Young Lee, assistant professor of management and marketing at the University of Dayton. “Tipping is a tool to display the tipper’s social status.”

Another way to make diners feel like big spenders: sprinkle a little gold around. The extra sparkle in the surroundings signals status and prosperity, making diners want to flash their affluence too. In a 2018 study, Prof. Lee’s research found that diners left 2.6% more in tips when the bill was presented in a gold folder, as opposed to the common black folders. Results were consistent when Prof. Lee’s team experimented with gold napkins and gold tablecloths.

Color also plays a role in how restaurants look in social-media photos. According to a study commissioned by SevenRooms, a restaurant-reservation-management platform, 22% of Americans have gone to a restaurant based on what the food or atmosphere looked like on social media.

Instagram, for instance, has upended one longstanding rule of thumb. “The color blue serves absolutely no culinary purpose. There are no blue foods in nature, and marketers long warned that blue wouldn’t sell,” says Prof. Spence. “And then came Instagram.”

Which is to say, blue looks great in photos. Now there are blue smoothies, blue cocktails, blue bottles and blue juices. Of course, it isn’t just blue food. It is food in motion, it is food on fire, and it is food as aspiration. Prof. Spence gives social media some of the credit for the breakout popularity of rosé. Pink wine is just more fun in photos.

“People say they need an ‘Instagrammable moment’ in their design,” says Prof. Robson. Whether it is a neon sign, a green wall or some other visual distinctive to the restaurant, diners want to let their friends know, “I was there.”

Ms. Baker is a writer in Philadelphia. She can be reached at reports@wsj.com.