How Credit Cards Affect Our Brains

It’s been known for decades that credit cards encourage spending. But why that happens still isn’t entirely clear. New research offers some fresh insight into the causes—and how consumers might be manipulated in an increasingly cashless society.

Research on credit-card spending has tended toward the explanation that delaying payment removes a barrier to purchases in shoppers’ minds. A study published in February in Scientific Reports found evidence of another kind of trigger. Differences it found in brain activity between shoppers planning to use a credit card and those planning to buy with cash indicate that buying on credit doesn’t just ease shoppers’ inhibitions, it actively encourages purchases, the researchers say.

The upshot: When people are shopping with credit cards and see a product they like, the neural network in the brain that produces a sensation of reward perks up, which seems to create a craving to spend, says Sachin Banker, assistant professor at the University of Utah, who worked on the study as a Ph.D. student at the MIT Sloan School of Management.

“You’re basically feeling more reward when you shop with credit cards,” he says. “We don’t see that with cash. It was actually a very stark difference.”

Researchers used a form of magnetic resonance imaging to measure the brain activity of the study subjects as they participated in a shopping exercise. Each participant was shown a total of 84 everyday products over the course of three sessions and was asked whether they would buy each product at the stated price. Half the products were offered for purchase by credit card and half for purchase with cash. None of the products cost more than $50.

The differences in the shoppers’ brain activity support the hypothesis that after repeated credit-card purchases over time the brain learns to anticipate the rewards of credit-card shopping, according to the report. And that suggests that consumers could be conditioned to spend through the use of various sensory rewards in new payment systems, Dr. Banker says. For instance, with digital payments the use of particular sounds or vibrations on your smartphone when you make certain purchases but not others could, over time, teach your brain to anticipate rewards for buying specific products while you’re shopping.

Dr. Banker adds that further research could be done to see if the study’s theories hold true at higher prices. It also could study consumers who tend to overuse or misuse credit cards, to understand further why they act as they do. This study focused on people who mostly paid on time and used credit cards appropriately. Understanding brain patterns for other types of consumers could help lead to solutions that attempt to pre-empt harmful spending behaviour, Dr. Banker says.

The number of U.S. billionaires in the world reached 870 in mid-January, outpacing the number in China for the first time in 10 years, according to a snapshot of the wealthiest in the world by the Hurun Report.

The U.S. gained 70 billionaires since last year, powered by a rising stock market, a strong dollar, and the insatiable appetite for all things AI, according to the 14th annual Hurun Global Rich List . China gained nine billionaires overall for a total of 823. Hurun is a China-based research, media, and investment group.

“It’s been a good year for AI, money managers, entertainment, and crypto,” Rupert Hoogewerf, chairman and chief researcher of the Hurun Report, said in a news release. “It’s been a tough year for luxury, telecommunications, and real estate in China.”

Overall, the Hurun list—which reflects a snapshot of global wealth based on calculations made Jan. 15—counted 3,442 billionaires in the world, up 5%, or 163, from a year ago. Their total wealth rose 13% to just under $17 trillion.

In November, New York research firm Altrata reported that the billionaire population rose 4% in 2023 to 3,323 individuals and their wealth rose 9% to $12.1 trillion.

Elon Musk, CEO of electric-car maker Tesla and right-hand advisor to President Donald Trump, topped the list for the fourth time in five years, with recorded wealth of $420 billion as of mid-January as Tesla stock soared in the aftermath of the U.S. election, according to Hurun’s calculations.

The firm noted that Musk’s wealth has since nosedived about $100 billion, falling along with shares of Tesla although the EV car maker is benefiting on Thursday from Trump’s 25% tariff on cars made outside the U.S.

According to the Bloomberg Billionaires Index, Musk’s wealth stood at about $336 billion as of the market’s close on Wednesday, although measuring his exact wealth —including stakes in his privately held companies and the undiscounted value of his Tesla shares—is difficult to precisely determine.

The overall list this year contained 387 new billionaires, while 177 dropped off the list—more than 80 of which were from China, Hurun said. “China’s economy is continuing to restructure, with the drop-offs coming from a weeding out of healthcare and new energy and traditional manufacturing, as well as real estate,” Hoogewerf said in the release.

Among those who wealth sank was Colin Huang, the founder of PDD Holdings —the parent company of e-commerce platforms Temu and Pinduoduo—who lost $17 billion.

Also, Zhong Shanshan, the founder and chair of the Nongfu Spring beverage company and the majority owner of Beijing Wantai Biological Pharmacy Enterprise , lost $8 billion from “intensifying competition” in the market for bottled water. The loss knocked Zhong from his top rank in China, which is now held by Zhang Yiming founder of Tik-Tok owner Bytedance. Zhang is ranked No. 22 overall.

Hurun’s top 10 billionaires is a familiar group of largely U.S. individuals including Jeff Bezos, Mark Zuckerberg, and Larry Ellison. The list has France’s LVMH CEO Bernard Arnault in seventh place, three notches down from his fourth ranked spot on the Bloomberg list, reflecting a slump in luxury products last year.

Nvidia CEO Jensen Huang is ranked No. 11 on Hurun’s list as his wealth nearly tripled to $128 billion through Jan. 15. Other AI billionaires found lower down on the list include Liang Wenfeng, 40, founder and CEO of DeepSeek, with wealth of $4.5 billion and Sam Altman, CEO of OpenAI, with $1.8 billion.

Also making the list were musicians Jay-Z ($2.7 billion), Rihanna ($1.7 billion), Taylor Swift ($1.6 billion), and Paul McCartney ($1 billion). Sports stars included Michael Jordan ($3.3 billion), Tiger Woods ($1.7 billion), Floyd Mayweather ($1.3 billion), and LeBron James ($1.3 billion).

Wealth continues to surge across the globe, but Hoogewerf noted those amassing it aren’t overly generous.

“We only managed to find three individuals in the past year who donated more than $1 billion,” he said. Warren Buffet gave $5.3 billion, mainly to the Bill and Melinda Gates Foundation, while Michael Bloomberg —ranked No. 19 with wealth of $92 billion—gave $3.7 billion to various causes. Netflix founder Reed Hastings, ranked No. 474 with wealth of $6.2 billion, donated $1.1 billion.

How Credit Cards Affect Our Brains

Buying with plastic doesn’t just eliminate a barrier to buying. It actively encourages purchases.

The U.S. now has more billionaires than China for the first time in a decade, driven by AI and a booming stock market.