Does Working With Robots Make Humans Slack Off?

A new study suggests that people pay less attention to detail if they think a machine is backing them up


By Susan Pinker

Robots can perform surgery, shampoo someone’s hair, read a mammogram and, of course, drive a car. A chatbot could probably write my column, if I let it. Now that machines can do nearly everything humans do, the question is what effect they have on human motivation. Do they make our lives easier and more efficient, or do they turn us into slackers?

A study published in October in the journal Frontiers in Robotics and AI has an answer: A person who works alongside a robot is less likely to focus on details than when he or she works alone. Anyone who has worked in a team knows that one or two people usually carry the load while the others sit back and watch; researchers call this “social loafing.” It turns out that people treat robots the same way.

The study was led by Helene Cymek of the Technical University of Berlin, who has previously studied social loafing involving human partners. “When two pilots are in a cockpit monitoring the dashboard, they each reduce their effort. [Airlines require] two people because they want to increase safety. They call this the four-eye principle. But we found social loafing,” Cymek said.

For the new study, she and her colleagues recruited 44 volunteers to inspect electronic components for manufacturing errors such as bad welds or seams—a task that, in factories, is often performed by humans paired with robots. The volunteers were divided into two groups. One worked alone, while the other was told to double-check components that had already been inspected by a robot named Panda. People in that group were shown Panda—an articulated arm with a visual sensor on the end—on their way into the lab and heard it humming along as they worked.

But in fact, there was no robot at work. Both groups were deliberately given a set of components that included the same number of mistakes, so if the two groups were giving the same degree of attention to the task, their results should have been roughly the same. Instead, the researchers found that the humans working alone picked up an average of 4.2 out of 5 errors, while those who thought they were being assisted by a robot detected an average of 3.2—20% worse.

It’s not a huge difference, but if you think about quality-control teams where humans and AIs work together on medical imaging or aircraft navigation, it’s clear that the phenomenon of social loafing could potentially carry a high cost. For instance, Cymek notes, it’s known that in mammography screening, it makes a difference if a radiologist is checking an image for the first time or double-checking someone else’s work: “If the person knows it’s been checked first, they slack off.”

This finding doesn’t exactly boost my confidence in self-driving cars, even if there’s a human at the wheel to take over in an emergency. “People take advantage of the support that is offered—they’re over-reliant on the system,” Cymek said. “They look but do not see.”

Appeared in the November 25, 2023, print edition as ‘Does Working With Robots Make Humans Slack Off?’.

The Long-Term Benefits of Hands-On Fathering

A new study shows that fathers who feed, change and play with their young children are making a major contribution to their development.

A Japanese study found many advantages for children of highly involved fathers. PHOTO: GETTY IMAGES

By Susan Pinker

The blockbuster movie “Barbie” depicts men as utterly useless. The film’s younger guys dress in fake fur and act like Neanderthals, while the middle-aged men who have jobs are portrayed as incompetent nincompoops. Some are eye candy for the Barbies, but they’re all socially awkward. They can’t even play the guitar.

In the real world, however, there is at least one thing men are good at: playing with their babies. Over the last 20 years, research has consistently shown that fathers have a unique way of engaging with small children. Horsing around is more common with fathers than it is with mothers, especially as infants grow into toddlers and preschoolers. Vigorous bouncing, lifting, tossing and chasing take over from more gentle play, and this roughhousing leads to better self-control and school readiness as children turn 5, studies show. The father’s rough-and-tumble play is also connected to better gross-motor skills in the child, regardless of the father’s income or education level.

A vast new study, published in the journal Pediatric Research this past summer. adds weight to the idea that a father’s hands-on involvement underpins a child’s later ability to self-regulate and problem-solve. Led by Tsuguhiko Kato, a researcher at Japan’s National Center for Child Health and Development, the study started with over 100,000 Japanese babies born between January 2011 and March 2014. The researchers narrowed the group to first-born, healthy, singleton infants; babies whose mothers had experienced any post-partum depression, or who were hard to soothe at one month of age, were also excluded.

The result was a sample of 28,040 children. At intervals of six months, from one month of age to their third birthday, each child’s mother was asked to rate the father’s participation in early child-rearing, including feeding, changing diapers, bathing, dressing, playing at home or outdoors, and putting the child to sleep. Japanese fathers are typically less involved in child-rearing than North American fathers, but when the researchers examined the children’s milestones at age 3, they discovered that children whose fathers invested more time in their care showed better gross and fine motor skills, problem solving, and social skills than children whose fathers were not as involved.

There was no difference between the language skills of kids with involved versus aloof fathers. But “the risk of developmental delay in children with highly involved fathers was 24% lower,” said Dr. Kato. That’s a significant benefit, worth overcoming the many obstacles that can prevent fathers from being involved in child-rearing, such as a long commute, unpredictable work hours or family dynamics.

Because the father’s involvement was rated by the mother, it’s possible that the quality of the parents’ relationship may have influenced the series of assessments. “Children with parents who are in a good relationship could be in a good position,” Dr. Kato said. “There could be some bias related to the marital relationship that influences child outcomes.”

Raising small children is stressful. If the mother thinks the father is reducing the strain of nurturing their baby, she may give him high marks. But if she thinks he’s as useless as a Ken doll, she may not even let him try.

Appeared in the September 23, 2023, print edition as ‘The Long-Term Benefits Of Hands-On Fathering’.

The Saving Reach of Social Connections

Ties to others helped the survival chances of prisoners in Nazi concentration camps, a new study concludes

Prisoners at the Dachau internment camp after it was liberated in 1945. BETTMANN ARCHIVE/GETTY IMAGES

By Susan Pinker

There are many reasons to cultivate social bonds. Evidence shows that good health, well-being and career opportunities are tied to having a loyal network of family, friends and colleagues. Now a new study shows that the size of one’s social circle can even predict who has the best chances of survival under desperate conditions, such as in forced labor and concentration camps.

Testimony from Holocaust survivors has long suggested that loners were among the first to die in the Nazi concentration camps. In contrast, having a family member, friend, neighbor or colleague in the camp promoted survival. Even the act of sharing something small with another person, like a bit of food or a newspaper, could help.

In the new study, published in the Proceedings of the National Academy of Sciences last month, three Czechoslovak researchers tested these ideas empirically by analyzing data about the background and experiences of 30,000 Jewish prisoners who were deported to Auschwitz-Birkenau from the ghetto in Theresienstadt, in what is now the Czech Republic.

The data for the study were compiled by the Terezin Initiative Institute, a nonprofit group comprised of survivors. Lead author of the study Stepan Jurajda, a professor of economics at Prague’s Charles University, said that the institute “looked up information on every single one of these prisoners, including names, ages and addresses, and who traveled from the Theresienstadt ghetto to Auschwitz-Birkenau. And they found out whether these people survived the war.”

The researchers found that 10% of the deportees arrived in Auschwitz knowing a fellow prisoner, whether as a prewar neighbor in Prague, a fellow community member in the Theresienstadt ghetto, as workers in the same labor camp prior to Auschwitz, or as inmates on the same transport to the concentration camp. Only 6% of Auschwitz-Birkenau inmates survived. But any one of these social ties increased an inmate’s odds of survival by a third.

Social bonds were particularly favorable for women. Even inmates who had shared the same magazine in the ghetto had a greater chance of making it through Auschwitz, an indication of how important weak links can be in life-or-death situations. “It’s not just about ‘blood is thicker than water,’” said Jurajda. “The more people in the crowd you knew, the greater your chances.”

That conclusion fits the experience of Joseph Shalev, an 85-year-old retired ophthalmologist in Nevada whom I met recently. As a young child, Dr. Shalev was confined with his family in the Jewish ghetto in Vilnius, Lithuania. Between 1941 and 1943, almost all of the 40,000 Jews imprisoned there were murdered or died of starvation or disease.

Looking back, Shalev has no doubt that his father’s prewar social bonds were crucial to his family’s survival. As an engineer, his father had designed Vilnius’s sewer system. When rumors of deportations reached him, he built a network of hide-outs connected to the city’s sewage canals. These escape routes, in combination with his workplace relationships, were what saved him and his family.

“A Polish man who had worked for my father saved us by providing food and [a] hiding place” under the potato cellar of his house, Shalev told me. His family and 14 others lay prone in the cellar for 10 months until the Russians liberated Vilnius in 1944, when he was 6. “The employee was just one person,” said Shalev. “But if my father hadn’t known that Polish guy, we would not have survived.”

Appeared in the August 12, 2023, print edition as ‘The Saving Reach of Social Connections’.

Cannabis Is Linked to Mental Illness

A major new study shows that people who abuse the drug are more likely to be diagnosed with depression and bipolar disorder.


By Susan Pinker

There was a new smell to New York City on my first visit since the pandemic. The New York I remember from 2018 was scented with subway fumes, car exhaust and pretzels. Now the air was a heady blend of forest fire, car exhaust and cannabis.

Recreational marijuana was legalized in the state of New York in 2021. But even if cannabis is easy and legal to buy in 23 states and all of Canada, the risks of chronic use aren’t talked about much.

Several studies have shown that chronic cannabis use is linked to a higher incidence of schizophrenia among men in their early 20s, the age when the disease is usually diagnosed. The first paper on the topic, a Swedish study published in 1997, found that heavy cannabis use was associated with a sixfold increase in schizophrenia risk. In the decades since, social scientists have unearthed a strong link between heavy cannabis use and other severe psychological illnesses, including clinical depression and bipolar disorder.

Now a new longitudinal study has examined the medical records of all citizens of Denmark over the age of 16, some 6.5 million people in all, for patterns of diagnosis, hospitalization and treatment for substance use between 1995 and 2021. In the paper, published in the journal JAMA Psychiatry in May, Dr. Oskar Hougaard Jefsen of Aarhus University and colleagues showed that people who had previously been diagnosed with cannabis use disorder were almost twice as likely to be diagnosed later with clinical depression. According to the Centers for Disease Control and Prevention, cannabis use disorder is characterized by craving marijuana, using it more often than intended, spending a lot of time using it, and having it interfere with friends, family and work.

Even more dramatically, the paper also found that people with cannabis use disorder were up to four times as likely to be diagnosed later with bipolar disorder with psychotic symptoms. As is true of many psychological disorders, the increased risk was higher in men than in women, and the more a person consumed, the greater the risk. The study did not distinguish between different forms and concentrations of cannabis.

Though the association was strong, the authors note that they can’t say for certain whether chronic and heavy cannabis use induces psychosis, or whether people prone to mental illness are more likely to be heavy users. It makes sense that people who feel the symptoms of incapacitating depression or mania, or who sense apparitions or voices only they can hear, might try to self-medicate with cannabis. Without a randomized controlled trial, which would be unethical in the extreme, it’s hard to untangle these strands definitively.

But the study is still eye-opening due to its sheer magnitude. With so many people over so many years, there is very little statistical “noise.” And because the information was gathered from the national Danish Health Registry, there were few dropouts—often a big problem in longitudinal studies. As much as possible, the researchers confirmed that the symptoms of a person’s psychiatric disorder emerged after their chronic cannabis use and diagnosis, not before, and that they compared people who were alike in all ways except the frequency of their use.

Like cigarettes decades ago, cannabis is now widely considered a harmless habit: easy and legal to buy in most places, socially acceptable, and pleasurable in the moment. Over the long term, it may be safer than drinking alcohol. But is it really safe for you and your teenage kids? Only time—and more research—will tell.

Prenatal Stress May Make Children More Verbal

A new study finds that pregnant women with a high level of the stress hormone cortisol have children who learn language faster.


By Susan Pinker

Cortisol floods your bloodstream every time you feel stressed out. This biochemical messenger heralds an incipient attack—real or imagined—and instructs your body to gird itself for danger. But the hormone can have contradictory effects; it plays the role of hero or antihero, depending on the context. Doctors prescribe it to reduce inflammation and tamp down the immune system when it goes haywire, for example. But cortisol released during periods of extended psychological stress can also damage your heart and kickstart a major depression.

“Cortisol has a bad reputation,” says Anja Fenger Dreyer, a physician and a research fellow at the University of Southern Denmark. Studies have repeatedly linked high levels of stress-related cortisol to preterm births, extremely small newborns and postpartum depression in mothers. At the same time, Dr. Dreyer explains, “It increases during [a healthy] pregnancy and is good for fetal development. In preemies [cortisol] is used to help mature the organs, like the lungs, brain and heart.”

Dr. Dreyer is a lead co-author of a remarkable new study, presented in May at the annual European Congress of Endocrinology, which adds yet another dimension to the cortisol paradox. Researchers found that pregnant mothers who were anxious during their last trimester, and thus secreted lots of cortisol, gave birth to babies who became excellent listeners and talkers as toddlers. The more cortisol circulating in the mother’s bloodstream late in pregnancy, the more advanced the toddler’s understanding of words, and the more words they said between one and three years of age.

The researchers drew their data from the Odense Child Cohort study, which began with 2,500 healthy, pregnant women living in the Danish city of Odense from 2010 to 2012. After dropouts, 1,093 children remained in the study. To study the developmental effects of prenatal cortisol, blood samples were collected from the mothers during pregnancy. Researchers monitored the children in utero and examined them every two years after they were born, as well as taking samples of their blood and hair.

When the children were between the ages of 1 and 3, every three months the parents completed a standardized language survey, the MacArthur-Bates Communicative Development Inventory, which required them to tick off which words their toddlers understood or said from a list. According to this new study, the more cortisol produced by a pregnant mother during her third trimester, the more advanced her toddler’s language abilities.

The findings suggest that prenatal cortisol may be a bigger player in human development than previously thought. But there’s still much to untangle, including the role of sex differences. Intriguingly, the researchers found that boys whose pregnant mothers secreted more last-trimester cortisol produced more words, while girls exposed to greater cortisol understood more words. This may be connected to the fact that pregnant women carrying girls generally secrete more cortisol than pregnant women carrying boys. On average, girls’ language skills tend to be more advanced than boys’ in all populations, and cortisol may give us a clue as to why that is.

The Power of a Good Neighborhood

Research shows that children achieve higher levels of education when they grow up with affluent neighbors nearby


By Susan Pinker

Sociologists have long known that growing up surrounded by poverty is corrosive for a child’s life chances. The 2020 book “The Origins of You: How Childhood Shapes Later Life,” written by a team of four developmental psychologists, showed that children who grow up in disadvantaged neighborhoods are more likely to remain antisocial and badly behaved when they get older, while their peers in better neighborhoods mature and stop acting out. This is especially true of boys.

Similarly, the Harvard economist Raj Chetty has shown that the zip code a person grows up in helps to predict the likelihood that they will drop out of high school, get pregnant as a teenager or be incarcerated. Now a new study from the Netherlands has found that a key factor in a child’s ultimate level of education, even more important than their own family’s economic situation, is whether they grow up with affluent neighbors nearby.

Researcher Agata Troost and her colleagues at Delft University of Technology used a national database to track the address of every Dutch baby born in 1995, a total of 140,338 people, from birth to age 23. Using geolocating software, they drew up a socioeconomic profile for each child’s immediate neighborhood, calculating the percentage of neighbors who were affluent, middle class or disadvantaged.

After controlling for a number of other factors, including parents’ earnings and levels of education, the researchers found that a child’s own experience of wealth or poverty mattered less to their ultimate level of schooling than exposure to well-off neighbors. The data suggest that growing up in an affluent area, with well-maintained parks, libraries and soccer fields, as well as interactions with educated neighbors, could boost a poor child’s ability to see beyond her immediate horizon.

“Affluent families create neighborhoods and activities that create opportunities,” said Ms. Troost, and these advantages are shared with other children who happen to live nearby. The finding echoes an earlier study by Mr. Chetty and colleagues, which showed that having even one inspiring teacher in middle school can enhance a student’s career prospects. Whether in the classroom or on the street, it seems that social interactions outside the family can kickstart a young person’s motivation and ambition.

At the same time, the study also underscored the importance of the home environment. When parents are well educated, children are likely to be, too. Whether the family lives in a depressed, about-to-be-gentrified corner of a city or in an isolated rural town, the parents’ education acts as a protective halo.

And that’s the moral of the story: Neighborhoods can have different effects on different children, depending on how educated their parents are, whether they are male or female, and how much casual contact they have with people who are different from their own families. “Location, location, location” may be a real estate cliché, but we’re learning that it also holds true for children’s development.

Exercise Can Be the Best Antidepressant

New research finds that as little as 12 weeks of regular exercise can alleviate symptoms of depression as effectively as medication.


By Susan Pinker

One of the highlights of my pandemic workweek was the Zoom workout I did with a dozen fellow swimmers once we lost access to our pool. Most aspects of my life were upended, but the 7:45 a.m. home exercise session was a constant: a warm-up, two sets of resistance exercises designed by our loyal coach, then stretching and gabbing. None of us wanted to give up this routine when restrictions eased, and we’re still at it.

I feel more upbeat and quicker on the uptake on days when I do planks and squats. Now a new paper evaluating studies of the impact of exercise on mood shows that physical activity, of any kind, is just as effective as antidepressants at reducing feelings of anxiety and depression—and sometimes more effective.

Dr. Ben Singh, a research fellow at the University of South Australia, was the lead author of the study, which appeared in February in the British Journal of Sports Medicine. He and 12 other scientists combed the research literature for all randomly controlled studies published before 2022 that involved adding exercise to a person’s “usual care,” to see how physical activity might relieve psychological distress.

The group found 97 reviews, which together comprised 1,039 distinct randomly controlled trials and over 128,000 participants, many of whom had symptoms of depression. “Usual care” referred to whatever the person was already doing to stabilize their moods, whether it was taking antidepressants, seeing a psychologist, doing both or doing nothing at all. “We didn’t want them to replace their treatment with exercise but to add exercise into their day,” said Dr. Singh.

Statistical crunching revealed that as little as 12 weeks of exercise can mitigate depression, while often achieving faster results than antidepressants. “Any type of movement is effective: a bike ride, yoga or Pilates” said Dr. Singh. He mentioned that resistance training (like my Zoom workout) was best for reducing symptoms of depression, while yoga and Pilates were best at tamping down anxiety. “The higher the intensity, the better,” Dr. Singh said. “But just a walk around your neighborhood is effective, too.”

Exercise is free, rarely induces side effects and can muffle existing feelings of anxiety and depression, or even prevent their occurrence in the first place, according to a 2018 meta-analysis. Still, “It’s very rare that doctors say, ‘I need you to exercise three times a week, for at least 30 minutes, at a brisk walking pace,’” said Dr. Singh. A large Canadian study of 13,000 primary care physicians showed that while 70% mentioned exercise to their patients, barely 16% wrote a prescription recommending it. “Exercise is considered ‘complementary’ like acupuncture,” said Dr. Singh, but “there’s no evidence that acupuncture has any effect, yet there’s lots of evidence for exercise.”

Exercise isn’t a cure-all, and the study doesn’t establish how long the reprieve from depression and anxiety lasts. The authors write that the “effectiveness of physical activity diminished with longer duration interventions,” most likely because over time the participants exercised less often or stopped altogether.

And there’s the rub. Someone who is so depressed they can’t get out of bed might not be motivated to walk around the block, much less to do jumping jacks and burpees. That could be one reason why the uplifting effects of exercise are weaker for more serious forms of depression. Even if you do get started, if you’re feeling ill, making exercise a habit is so much harder than taking a pill.

Placebos Can Have a Real Effect on Guilty Feelings

A new study shows that taking a pill can have psychological benefits even when people know it contains no medicinal ingredients


By Susan Pinker

Placebos—medical interventions that contain no therapeutic ingredients—are a mainstay of randomized controlled trials, the gold standard of medical research. In these studies, one group of participants receives an experimental treatment and another gets a placebo, while both experimenters and participants remain in the dark about which group is which. That way, the results aren’t influenced by people’s expectations. It’s good research design, but if you were a patient enrolled in a clinical trial, how would you feel if you found out you were given a placebo instead of a possible treatment?

In fact, researchers have found that placebos can be effective even when they are “open.” Surprisingly enough, taking a sugar pill can be beneficial even when you know it’s a sugar pill. Now a new study published in Nature Scientific Reports last December shows that open placebos don’t just work for physical pain; they can also reduce negative emotions like guilt.

Led by Dilan Sezer, a doctoral student in clinical psychology at the University of Basel, the study recruited 112 healthy university students between 18 and 40 years old. “Then there was a baseline assessment of their guilt. Using a questionnaire, we asked, how guilty do they feel in general?” said Ms. Sezer.

At the next stage of the study, people were asked to write about a specific event in their past that made them feel shame for having treated someone shabbily, and the strength of their guilty feelings was assessed with a questionnaire. Then the participants were randomly assigned to one of three groups. The first was given a “deceptive” placebo: It contained no medicinal ingredients, but participants were told it contained herbs and essential oils that had been “shown to reduce guilt feelings.” The second group was given an “open” placebo and were told that it “does not contain any medicinal ingredients.” The third was a control group that received no intervention at all.

Afterward, each participant was asked to fill out the same questionnaire a second time. The findings were crystal clear: Both placebo groups showed a significant drop in guilt compared to those in the no-treatment control group. What’s more, “the difference between placebo groups was statistically indistinguishable,” Ms. Sezer said.

How can placebos work when a person knows they’re fake? Some researchers have speculated that a combination of hope and uncertainty leads the “brain to anticipate, seek out and identify new data or rewards,” writes Ted Kaptchuk, who leads the Program in Placebo Studies at Harvard Medical School. The human brain is constantly testing hypotheses about what might come next, even if we are not overtly aware of this process. Certain environments and rituals also create expectations about how we are going to feel, whether we’re seeing a play in a theater or participating in a study in a lab or clinic.

Ms. Sezer’s study reinforces the notion that we aren’t always completely rational about what can help us. She notes that her sample was small and included only psychologically healthy people, but she hopes the findings will be investigated further. “We don’t know yet if this will work in a clinical population,” she says, “but for everyday guilt in young people, it works.”

Do We Really Get Mellower With Age?

New research suggests that most people experience less stress once they reach their 40s and 50s.


By Susan Pinker

In my favorite documentary film series, “Up,” 14 British children from various backgrounds are followed by a film crew over 56 years. The first film was made in 1964, when all of them were 7, the last in 2019, when they were 63. Every seven years the director, Michael Apted, offered a new glimpse of the latest chapter in the subjects’ lives.

Now, in a science-imitates-art moment, a 20-year-long study has been published in the journal Developmental Psychology that charts the lives of a much bigger sample: 3,000 randomly selected Americans between the ages of 22 and 77. Each subject participated in three interview “bursts,” in 1996, 2005 and 2017, in which they talked to researchers every day for eight days. The goal was to map out the number of stressful events participants faced at each stage of life and how they reacted to these challenges.

“One of the things I really appreciate is the value of talking to someone about their day, just hearing their voice, every night for eight consecutive nights,” said David Almeida, a professor of human development at Penn State University, who has led the study since the beginning. “We really wanted to capture the ebb and flow of daily life as it was happening.”

The researchers found that stress drops steadily as we get older. Life is particularly fraught in young adulthood, when we face more stressful situations and have fewer psychological resources to deal with them. By the time we reach our 40s and 50s, our emotional lives tend to settle down. While this period is often portrayed in popular culture as a time of midlife crisis, divorce and career upheaval, the researchers state that “our findings reveal a clear and robust benefit with age.”

The decline of stress over time is an average trend. It isn’t necessarily true for neurotic people who are always wound up or for people facing ongoing pressures, including members of some minority groups. (The team will analyze such differences in future studies.) But for the majority of Americans, aging brings less strife.

The researchers offer an explanation for this pattern. Young adulthood is marked by numerous transitions: graduating from college, finding a job, navigating financial independence, getting married and having small children. “Younger adults have more strain, more role conflict. But by midlife you’re more established in your career, and your children are growing up,” said Dr. Almeida.

Another explanation, he added, is that “When we don’t have as much life left, we want to maximize the time we have.” We’re more motivated to avoid jerks and futile conflicts. Finally, by midlife we have more experience in solving problems. “When I was younger, I would freak out if I had a plumbing problem,” Dr. Almeida said. “But now I know a plumber I can call.”

Stress is a biochemical reaction that evolved to help keep human beings alive when we were hunters and gatherers. Now that most of us work in cities, why is it still with us? “We’ve done a series of studies searching for its benefits,” Dr. Almeida explained. “One shows that stress forces you to solve novel problems; people who experience more daily stress also perform better on cognitive tasks.”

What’s more, on stressful days people tend to have more social contact. If you have a problem and call up your friend, she can’t necessarily provide a solution, “but you get the social support that you need to deal with it,” said Dr. Almeida. The benefit of that social interaction, especially in young adulthood, seems to outweigh the angst of stress.

How Happy Can a Windfall Make You?

A new study finds that receiving an unexpected cash gift can improve well-being, but only up to a point.


By Susan Pinker

How would you feel if an anonymous benefactor gave you $10,000 to spend within the next three months, no strings attached? Would suddenly being flush with cash fill you with joy?

That question sparked a remarkable study published this month in the Proceedings of the National Academy of Sciences. Lead author Elizabeth Dunn, a professor of psychology at the University of British Columbia, along with her doctoral student Ryan Dwyer, knew from prior research that there tends to be a correlation between receiving a sum of money and being happier. But those studies didn’t untangle the direction of causation—whether happier people made more money, or whether money made people happy.

The opportunity to dig deeper fell in their laps in 2020, when two anonymous donors offered to give Chris Anderson, the CEO and chief curator of TED, $2 million to distribute to worthy individuals around the world. Mr. Anderson then contacted Prof. Dunn. Might she be interested in studying the impact of these gifts? “Hell, yeah,” she answered.

The TED organization, which ran the study, found participants for the “mystery experiment” by reaching out to English-speaking Twitter users. Individuals from three low-income countries—Brazil, Indonesia and Kenya—and four higher-income countries—Australia, Canada, the U.S. and the U.K.—were invited to participate in “a unique social science experiment…Before you are told the nature of the experiment, we will ask you specific questions regarding your behavior, background, personality and other matters,” the message began.

After weeding out those whose lives might be endangered by a sudden influx of cash, the study ended up with 300 participants. Two hundred were randomly chosen to receive $10,000 via PayPal. The remaining 100 respondents served as the control group. All participants had completed a baseline survey about their psychological well-being and annual earnings at the beginning of the experiment, then completed follow-up surveys one, two, three and six months after the cash was distributed. Members of the control group received $25 each time they filled out a survey.

The researchers found that, as might be expected, a big windfall made people happier than the drip-drip-drip of repeated $25 gifts. But the money didn’t have the same effect on everyone. “The gains were greatest for recipients who had the least,” the paper found. People in lower-income countries who received $10,000 gained three times more happiness, based on the self-reported surveys, than those in higher-income countries. For recipients whose annual income was $100,000 or above, the gain in happiness was diminished.

Comparing participants in the same country, those who made $10,000 a year gained twice as much happiness from the windfall as those making $100,000 a year. “This is consistent with a mountain of research showing that the more we have of something, the less we feel about increases. Those with lower income get a better boost,” said Prof. Dunn.

In 2021, four billion people worldwide lived on less than $6.70 a day. The new study suggests that if any of them got a cash gift with no strings attached, a smile would likely appear on their face. Perhaps such giving should become a Thanksgiving tradition, along with turkey and football. “My fondest wish is that people will emulate what this couple did,” said Prof. Dunn. For people who have money to spare, giving it away creates “more happiness than if you kept it for yourselves.”