When it comes to vices during the pandemic, simply put, it's been difficult to say "no." Drinking an extra glass of wine here, eating half a birthday cake in one sitting there — whatever it takes to escape the constant strain of life under lockdown. That seemed reasonable in March, anyway.
But nine months on, when experience has demonstrated that chain-smoking a pack of cigarettes doesn't compensate for human interaction, why do bad habits continue to compel us?
The prolonged traumatic, or "chronic toxic," stress that most people have been experiencing throughout the pandemic makes it more difficult to keep desires in check, and it in turn promotes illogical pleasure-seeking, said Dr. Robert Lustig, a professor emeritus of pediatric endocrinology at the University of California, San Francisco, and author of "Metabolical." In scientific terms: When brains are flooded with the stress hormone cortisol on a long-term basis, it inhibits the function of the prefrontal cortex, leading to excessive activation of the "reward center" of the brain — triggering the excessive baking, drinking, smoking and shopping that filled the idle hours of 2020.
"Dopamine is the reward neurotransmitter. It is held in check by the prefrontal cortex. When that inhibition is released, the reward center looks for hedonic stimuli," Lustig said. "Those can be chemical — cocaine, heroin, nicotine, alcohol, sugar — or behavioral — shopping, gambling, internet gaming, social media, pornography."
Take the beloved carbohydrate sugar. Early in the pandemic, a baking frenzy swept the country, offering both a relatively accessible quarantine hobby and a constant supply of carbs. Like hand sanitizer and toilet paper, flour and yeast went from lowly supermarket staples to hot-ticket items quickly nabbed from store shelves.
But what exactly about baking makes it so suited for quarantine? Was it the diversion of dough-kneading or something more hedonistic? While total cookbook sales in the U.S. grew by 15 percent in the first nine months of the year, sales of bread-specific books grew by 145 percent, according to NPD Group data. That's 200,000 more bread cookbooks than were sold in 2019. Meanwhile, sales of cookbooks about vegetarian and other comparatively healthy cuisines took a hit in March and April.
The preparation of baked goods in quarantine was clearly driven by more than just the joy of cooking, Lustig said. "Baking means carbohydrates and particularly sugar — both for diversion and for addiction. And aren't they really the same?" he said.
The jump from sifting flour to full-blown addiction might sound extreme, but it raises the question of why exactly people turn to certain things for comfort even when they know the feeling is fleeting.
"That's the million-dollar question," said Laurie Santos, a professor of psychology at Yale University and host of "The Happiness Lab" podcast. "We know neuroscientifically that there's a disconnect between the kinds of things that we want and the kinds of things that we like. Wanting is a motivational process. Liking is how you're going to feel when you get it."
She said the disconnect is strongest in the domain of addictive drugs: craving, or "wanting," the drug will drive people to extremes to obtain it, but the actual payoff, or "liking," is low because they're already habituated to it.
Download the NBC News app for the latest news on the coronavirus
"The flip side is that we don't have 'wanting' for the things that are going to work. Things like taking time to experience social connection, doing nice things for others, taking time to experience gratitude. We just don't have mechanisms to seek that stuff out. We don't realize that that's what's missing," Santos said.
One thing that was widely wanted during the pandemic: alcohol. Women, in particular, were more susceptible to stress drinking in quarantine. As a group, they experienced decreased job security and increased social isolation — factors that historically have driven alcohol consumption.
In April, with nearly all Americans under stay-at-home orders, online alcohol sales increased by more than 500 percent over the previous year. Online sales dipped after the panicked early days of the pandemic as surviving bars and restaurants temporarily opened, but even in October, online sales of alcohol outperformed sales of most other consumer goods categories, according to Nielsen.
A more counterintuitive habit that made a comeback was smoking. Given the coronavirus's effects on the respiratory system, lighting up a cigarette this year may have seemed unfathomable to some, but sales indicate that the chemical incentive of nicotine remained a draw for many. Overall declining U.S. tobacco sales were curbed slightly in March through October. And it's not just stress that's fueling consumption. Companies attribute higher sales to a hike in disposable income for Americans who got a boost from stimulus payments and spent less money on social activities like dining out — which meant they had more occasions to smoke at home.
As Americans coped with pandemic-fueled discretionary spending, it wasn't just Big Tobacco that benefited: This Cyber Monday, Nov. 30, the first Monday after Thanksgiving, became the biggest online shopping day in U.S. history, with a grand total of $10.7 billion in purchases — a number as indicative of the collective brain's search for gratification as any other. And one category that surged notably was self-care.
"Buying new material possessions just simply doesn't make us as happy as we think. In fact, we'd be better off spending money on other people."
"Self-care is the ultimate form of expressing self-love," said Colleen McCann, the author of "Crystal Rx" and founder of a fashion-meets-mysticism brand, Style Rituals. McCann's services include energetic closet cleanings and self-affirming crystal and Tarot readings, after which clients receive a highly curated "me-time" kit and a mood board. Even as a high-end, niche offering, Style Rituals has been gaining business even though its services have moved fully online, McCann said.
Projections of consumer spending from RetailMeNot indicate that people will spend more money on gifts for themselves than on their parents, in-laws or best friends this holiday season. But egocentric shopping won't bring the holiday cheer that one might expect, Santos said.
"Buying new material possessions just simply doesn't make us as happy as we think. In fact, we'd be better off spending money on other people. Doing nice things for others seems to be actually a thing that makes us happy over time," she said.
With the help of vaccines, the return of society may be just the thing to replace instantly gratifying habits like impulse-spending stimulus checks with more lasting enrichment.
"After lockdown, we're going to get these amazing fresh starts on the routines we have, how we interact, who we interact with," Santos said. "It really will give us opportunities to build in more positive habits and use what we learned during this time to create a more nutritious life for ourselves."