Early Lessons in Self-Control Bring Lifelong Benefits

Aggressive boys who got behavioral training show more stability as adults 30 years later


By Susan Pinker


In the early 1980s, a group of psychologists, led by Richard Tremblay of the University of Montreal, set out to study early behavior problems in 250 boys living in poor Montreal neighborhoods. The boys had been nominated by their teachers as highly aggressive, oppositional or hyperactive. All were native French speakers whose parents had no more than a high school education.

Researchers divided the boys, ages 7 to 9, into two groups at random by drawing their names from a box. Those in the treatment group received two years of coaching in social skills and self-control—with classes that involved verbal instruction, modeling and rehearsing desired behavior—and positive verbal and material feedback from adults. The instructors met separately with the child’s teacher and parents to bolster these lessons. The idea was to help the boys develop non-aggressive strategies for dealing with common social situations, like what to do if a classmate bumps your desk.

The boys in the control group, meanwhile, received the treatment typically offered to disruptive students at the time—being exiled to the corridor or the principal’s office.

The study aimed to see how such training might affect these high-risk boys over time, so the researchers followed up with them from ages 10 to 24. They found a large improvement in the self-control, attention and social skills of the boys in the treatment group. By late adolescence, these boys also performed better academically. And in early adulthood, they were more likely to be members of a social group.

Now, more than 30 years later, Dr. Tremblay and a new set of colleagues, including the French economist Yann Algan and doctoral candidate Elizabeth Beasley, have returned to the experiment to examine the progress of the boys as they have become men. Their new study, recently published in the American Economic Review, used school and government records to see whether the original participants graduated from high school, had police records and were employed. They also looked at how much tax they paid, their marital status and whether they received social assistance.

It turns out that early intervention made a significant difference for the participants—and society—in the long run. Of the highly aggressive boys who didn’t receive special coaching, 69% dropped out of high school, and 32% had a criminal record. Among the boys in the treatment group, 55% dropped out, and 21% had a criminal record. As adults, men who had been in the treatment group were more likely to be married, earned some 20% more a year and were 40% less likely to rely on welfare or unemployment insurance.

The idea for the original study came from Dr. Tremblay, who started his career in Montreal at what was then the Pinel Institute for the Criminally Insane (now the Philipe Pinel National Institute of Legal Psychiatry). Then as now, most of the men at the Institute had committed violent crimes. “I worked for three years with these mentally ill offenders, and almost all of them had killed someone,” Dr. Tremblay told me. “I decided then to focus on juveniles and possible juvenile delinquents.”

This remarkable experiment shows that early treatment can have an outsize impact on the lives of vulnerable boys. The researchers conclude, “We estimate that $1 invested in this program around age 8 yields about $11 in benefits by age 39.”

It would seem that there is little to be gained and much to lose if we take the watch-and-wait approach with disruptive little boys. The stakes are just too high.

Appeared in the August 13, 2022, print edition as ‘Early Lessons In Self-Control Bring Life-Long Benefits’.

How the Upwardly Mobile Feel About Wealth

A new study suggests that people who become affluent have less sympathy for the poor than the born rich do


By Susan Pinker


The rags-to-riches story is such an enduring part of American identity that it somehow feels unpatriotic to doubt it. Consider celebrities like Dolly Parton, Ray Charles or Arnold Schwarzenegger—to name just a few—who grew up poor and succeeded through outsize talent and sheer grit. Those who were born rich, however, don’t get the same respect. In a 2012 Pew Research Survey, just 27% of respondents said they admired the rich, but when a follow-up question asked whether they admired those who had earned their wealth, 88% agreed.

This gap is explored in a recent study published in the journal Social Psychological and Personality Science. The lead author, Hyunjin Koo, a doctoral candidate in psychology at the University of California, Irvine, explained why she was drawn to investigating the nuances of the American Dream: “People seem to really like and admire those who pulled themselves up by their own bootstraps, and expect them to care about the poor and about social welfare,” she wrote in an email.

Ms. Koo wondered whether people who started out at the bottom and achieved high status would support public policies to assist other strivers like themselves. Or, having successfully climbed the socioeconomic ladder, would they perceive upward social mobility as less difficult? “If I did it, why can’t they do it?” Ms. Koo asked rhetorically.

The research team, which included psychology professors Paul Piff at U.C. Irvine and Azim Shariff at the University of British Columbia, began with two studies designed to assess Americans’ attitudes to the rich. Six hundred randomly selected adults were asked to rate two groups: the “born rich,” who had inherited their wealth, and the “became rich,” who had earned it. Which group would be more likely to attribute poverty to external circumstances, for example, or feel empathy toward the poor?

The results showed that people considered the “became rich” more likable and also expected them to be more supportive of the less fortunate. A second set of studies, however, found that these attitudes aren’t in line with reality. This time the research group recruited 1,000 people whose earnings were in America’s top quintile, or more than $142,500 a year. The researchers then sorted this sample into two camps, the “born rich” and the “became rich,” by parsing their financial histories on a questionnaire.

Both groups were then asked to rate themselves on statements like “I demand the best because I’m worth it,” “I sometimes feel guilty about how much money I have compared to others,” and “In the U.S., it is difficult to improve one’s socioeconomic conditions.” In tabulating their answers, the researchers discovered that people who inherited their wealth were more likely to sympathize with those living in poverty and also more likely to support policies that would give the poor a leg up.

It’s the reverse of what one might expect. “People assume that those who had to climb the ladder better understand the struggle and therefore will be more sympathetic to the poor. Maybe they do understand, but the conclusion they come to is that it’s actually less of a struggle and thus less sympathy is in order,” said Prof. Shariff.

How Children Use Conflict to Win Popularity

New research shows that as early as the third grade, a student’s concerted aggression can raise their status among schoolmates


By Susan Pinker


If you’ve ever watched someone start an argument just to win it, then you’ve witnessed a maneuver the person has likely been honing since third grade. Stirring up conflict is how some young children manage to achieve top-dog status, according to a study recently published in the journal Personality and Individual Differences.

The idea that aggression can stoke a certain popularity isn’t new, says Brett Laursen, the lead author and a psychology professor at Florida Atlantic University. But the study showed a pattern among schoolchildren that stemmed from aggressors creating repeated conflicts; classmates would often submit rather than engage.

When researchers use the term “popularity” to describe the type of status involved, it’s not the usual connotation. “We don’t mean that other kids really like these kids,” said Dr. Laursen. “It’s more a sign of dominance. Popular kids set standards and control resources, like who sits next to you at lunch, or who gets invited to your birthday party, or who pays attention to you.”

Aggression doesn’t necessarily mean using physical force, he said. “Always hitting other kids can backfire. It’s much safer to use conflict—without hitting—to get others to back down…You just need disagreements where people demonstrate their fealty to you, because they’re afraid of what might happen.” Yet being aggressive in order to climb the social ladder doesn’t work for everyone, he added. “That’s the head scratcher.”

To explore the issue, Dr. Laursen, working with doctoral candidates Michael Yoho and Sharon Faur, asked 356 elementary-school students—all third-, fourth- and fifth-graders—to fill out detailed questionnaires near the beginning of their fall semester. The kids were queried about their opinions and beliefs, and about how many disagreements they’d had the day before and with whom. They were asked to nominate classmates who “talk bad about others behind their backs,” who “get into trouble at school, or who “hit, push or shove others.” There were also questions about who the students would choose to spend time with or avoid. Thus, the researchers got an overview of the social dynamics of each class near the beginning of the year. At the end of the semester, the researchers asked the same students to complete the questionnaires again.

The results showed that children who maintained a frequent pattern of aggression had raised their status at the end of the term, while those who didn’t continue their confrontational behavior failed to get the popularity boost. In short, a small number of students in each grade kept initiating disagreement, presumably with the intention to command respect. Dr. Laursen added, “Most of these disagreements were not big arguments, but rather displays of dominance, say, overruling someone’s suggestion, just to let others know who’s the boss.”

What sets these students apart is their tendency to “think strategically about manipulating others,” suggested Dr. Laursen, adding that it’s likely a lasting trait. “For people who care about their status, a disagreement is never just a disagreement. Whether you’re 15 or 50, everything is an exercise in maintaining and improving popularity.”

Other research has shown that such belligerent behavior, rather than being penalized, is rewarded even more at older ages. That may paint a bleak picture of our social world, but at least it describes only a small cohort of people. As Dr. Laursen points out, society tends to rely on pecking orders of one kind or another. Perhaps some of these younger toughs will yet have time to find less combative ways to rise in status. We can only hope.

To Enjoy Social Contact, Choice Matters

 New research shows that people are least happy when they don’t have control over whether to spend time alone or in a group

By Susan Pinker


Whether our homes became refuges or prisons over the last two years, there is no doubt that the pandemic dramatically curtailed our social autonomy. We could no longer decide if and when to socialize, or even with whom. If we were lucky enough to have a home, we were stuck with our fellow inmates.

Research just published in the Journal of Happiness Studies now reveals that when it comes to happiness, having a choice is key. People who don’t choose to be social but end up surrounded by other people rate themselves as unhappiest. In contrast, folks who opt to be social and then find themselves in the company of others were ecstatic.

“Our culture is so focused on how positive interactions can be—just think of FOMO—that we don’t consider the alternative,” said the study’s lead author Liad Uziel, a psychology professor at Bar-Ilan University in Israel. “If you choose to be in a social situation, then you are likely to get more out of it. But your well-being is likely to drop if you didn’t choose it.”

The occasional period of time alone brings happiness to everyone, as long as that person chooses it.

The study, published with fellow Bar-Ilan psychology professor Tomer Schmidt-Barad, recruited 155 university students as participants. Every time the students received a text reminder on their phones, they had to report what they were doing and with whom, if they had any control over who they were with, and how they felt about it all. As Dr. Uziel described it: “How satisfied were they—their positive and negative experiences at that moment, how meaningful they found what was going on at that time, and how much control they had over the situation they were in.” The participants were pinged three times a day for a total of 10 weekdays, which yielded a mountain of data: 4,300 status reports.

Once the numbers were crunched, the researchers discerned several patterns. When people found themselves in social environments, whether chosen or unchosen, participants’ ratings of their experiences tended to the extreme, with higher highs and lower lows. “This means that our emotions are so much more intense when we’re with other people compared to when we’re alone,” Dr. Uziel said. Participants found themselves in environments they hadn’t chosen—such as classrooms and workplaces—about 30% of the time.

Being alone is more predictable, while being with others always presents surprises, he added. He used watching a soccer game as an example: “When you are alone and your team scores a goal, it’s exciting. But it’s way more exciting if you’re with other people—you experience it more powerfully.” This doesn’t mean that time alone is to be avoided, he said; the data show that “the occasional period of time alone brings happiness to everyone, as long as that person chooses it.”

Being with others also means having an audience, which heightens the impact of any experience. Performers know this, as does anyone who has ever watched a 5-year-old learning to ride a bike. Having an audience witness your achievement feels glorious. Of course, falling off your bike repeatedly is embarrassing when there’s an audience. These are the extremes of feeling that Dr. Uziel said were typical of social situations, whether or not they were chosen.

His next project will be to look at how the pandemic has changed the meaning of social situations. “It’s a risk, even for people who like to be with others,” Dr. Uziel said. “We shouldn’t push people to socialize.”

This dictum, he suggested, should influence how we design workplaces and family homes: “Give people as much choice as possible. Because forcing social contact on people is just a source of stress.”

There’s a Secret to Keeping Secrets

Research shows that a confidant who objects to the behavior that’s being hidden is more likely to spill the beans


By Susan Pinker


In a perfect world, our secrets would always be kept. But our world is imperfect. New research concludes that confidences about shame-inducing missteps, infidelities and imbroglios get exposed about a third of the time, which raises the question: What kinds of secrets are most likely to be revealed?

Jessica Salerno, a psychology professor at Arizona State University, and Michael Slepian, a professor of leadership and ethics at Columbia Business School, address this and other issues in a study published last month in the Journal of Personality and Social Psychology. Building on their own previous work and that of colleagues, they explore the nexus between secrecy and morality.

Dr. Slepian and Dr. Salerno were intrigued by the 2015 breach of the Ashley Madison website, which was created to help married people meet partners online in order to have affairs. The hackers “released all the data, which was hugely sensitive,” because they found the site morally objectionable, Dr. Slepian said. The two researchers set up a series of experiments and surveys to probe whether people were more likely to expose others’ secrets if they wanted to punish their behavior, as was the case with Ashley Madison.

Assembling nine different groups of 150 diverse participants, the researchers employed a variety of scenarios involving secrets that were hypothetical or taken from the news, or from the participants’ own experience. Some involved behavior that participants might find immoral; in a subset of those scenarios, the person committing the secret transgression had already been punished in some way. In each mini-experiment, details were subtly tweaked to see how the participants’ answers would differ. Was the secret act intentional or accidental, for example, or was anyone harmed? Participants were asked whether they supported disclosing someone’s secrets in each case.

The results showed that people were more likely to approve of spilling the beans if they found the secret behavior unethical. “The more morally outraged they felt, the more likely they were to reveal the secret,” said Dr. Salerno. In general, the moral code of the supposed confidante predicted their willingness to blab.

The secrets most likely to be revealed include specific lies (46%), harming another person or yourself (40%), illegal behavior (35%) and drug use (34%). By contrast, a confidence about a surprise event would only be revealed 18% of the time. If the secret was about someone who had already faced consequences for their behavior, a confidante would be less likely to reveal their secret because they’d already been punished, added Dr. Slepian. If the hidden behavior was unintentional, the secret was also likelier to be kept under wraps.

So how do you find a true confidant? Drawing on previous research, Dr. Slepian suggests avoiding the polite, rule-following, easy-to-offend person, especially if outgoing and loquacious; that’s the profile of someone most likely to spill the beans.

“What you really want is someone compassionate and assertive—especially if you’re looking for help—and someone who has the same sense of morality as you,” Dr. Salerno said. As she emphasized, keeping secrets is always difficult, but it’s especially hard if the shared information induces indignation or disapproval in your confidant.

A Gender Split Over Sniffing a Baby’s Scalp

Mothers get more aggressive and fathers less so when they inhale a chemical found in abundance on infants’ heads


By Susan Pinker


Imagine there was an odorless substance that made men less aggressive when they inhaled it but had the opposite effect on women. Sniffing it made women bolder. Would you go online and immediately click “buy”?

There’s no need: Our bodies produce this substance already. Hexadecanal, or HEX, is one of 6,000 volatile chemicals emitted by our body secretions, like tears and sweat, and in HEX’s case, by an infant’s scalp. Chemical signals like HEX fly under our conscious radar while altering our behavior, said Noam Sobel, a professor of neurobiology at Israel’s Weizmann Institute of Science, who calls his lab “very nose-centric.”

Two experiments—recently published in the journal Science Advances by Prof. Sobel, data scientist Eva Mishor and a team of colleagues—revealed that breathing in HEX influences our social behavior, dialing up aggression in women but attenuating it in men. This sex difference stunned the researchers. Based on mouse studies, they expected HEX to have a calming effect across the board. “Until the end of the second study I was skeptical about the results. HEX has no odor, yet our body reacts to it, and our behavior changes,” said Dr. Mishor.

The researchers made this discovery through a classic double-blind study in which 127 people were randomly assigned to an experimental or a control group, either inhaling clove oil infused with HEX or clove oil alone. Both groups played a computer-based negotiation game, believing that they were interacting with a remote opponent.

In reality the participants were playing against an algorithm that offered them egregiously unfair financial deals. “The ‘opponent’ proposes that he get 90% of a sum of money while you get 10%,” said Prof. Sobel, for example, and by the time participants reached the next phase of the experiment “they’re really mad at this person because they’re being so antisocial.”

That’s when the participants moved to a reaction-time game in which they could exact their revenge. When their “opponent” lost a round, the subject could punish them with a horn blast at different volumes, each illustrated by a face showing increasing signs of distress. “What we saw was a small but consistent difference between the HEX and the control subjects,” said Dr. Mishor. “Women exposed to HEX reacted 19% more aggressively, while men were 18.5% less aggressive.”

This was such an unexpected finding that the researchers did a second experiment. This time participants were tested while in a brain scanner. They were compared with themselves after inhaling either HEX or a dummy liquid. After being made to believe that money was being stolen from them in the game, would the same person react the same way in both conditions? Again, the women reacted with more aggression when exposed to HEX vs. the control liquid, this time by extracting more money from their “opponent” as retribution, while the men reacted less aggressively when exposed to HEX.

In the HEX condition, the men’s scans also showed greater connectivity to other areas of the brain, suggesting more neural engagement in regions that might control aggression. “We can look at the functional connectivity alone and distinguish men from women at 86% accuracy,” said Prof. Sobel.

What to make of the findings? The authors speculate that HEX is an ancient survival mechanism. Mothers exposed to the chemical signal would be more likely to defend their babies against threats, while fathers who inhale it would likely be less aggressive. Excited by the finding, Prof. Sobel thinks this is just the beginning of investigating olfaction as a driver of human aggression. “The next stage is to do this with actual babies’ heads instead of HEX in a jar.”

How to Bee Socially Distanced

Members of a hive instinctively stay farther apart when they sense a viral intruder.

illustration of bee's socially distancing


By Susan Pinker


Ants do it, bees do it, even baboons in the trees do it. Let’s do it, let’s keep our distance. It’s not so easy for humans, it seems, even when a contagious disease is rapidly spreading. But for honey bees? No problem. A study published last month in the journal Science Advances shows that honeybees start social distancing as soon as a bee brings a dangerous parasite into the hive.

Worthy of its name, the varroa destructor mite carries a virus that can destroy the colony from within. But the presence of the parasite is noticed by the colony’s healthy bees, who change their behavior to limit viral transmission, according to a suite of experiments led by Michelina Pusceddu and Alberto Satta, agricultural researchers at the University of Sassari, Italy, along with colleagues at three other European universities. “Varroa destructor is among the most serious threats to honey bees world-wide and has played a fundamental role in the decline of honey bee colonies all over the Northern Hemisphere in the past decades,” they write.

It’s a scientific parable for our times: A deadly virus descends on us out of the blue and exploits our social habits to expand its territory and reproduce. We’d be goners, except that evolutionarily speaking, a social species has a couple of ways to fight back. In some social animals, like ants, chimps and gorillas, the infected animal acts first: It might move slowly and look a little mangy, or skulk off to self-isolate. Other members of the group then know to avoid it.

But in the noble honeybee, the pest’s intrusion immediately alters the behavior of the healthy forager bees, who know their colony members by smell and can distinguish between the scent of healthy nest mates and those carrying parasites. The presence of the parasite in the colony prompts them to shift their activities away from the uninfected and more vulnerable members of the hive—the queen, the babies and their nurses.

The study’s authors call this change in the healthy bees’ behavior social distancing, and they expected to see more of it in the infested hives. Their experiment consisted of observing the behavior of bees in six colonies. Half of the hives had been regularly treated with oxalic acid, a natural pesticide, to make sure they were mite-free. A varroa destructor infestation bloomed naturally in the other three hives. The researchers videorecorded what went on in the hives over three consecutive days.

Forager bees are the explorers who leave the hive to find the nectar that nourishes the colony. Upon their return, they communicate where the sweetest flowers are, how big the nectar cache is and whether more foragers are needed. They do this by executing a waggle and vibration dance in the shape of a figure eight.

The comparison among hives revealed a stark difference in the forager bees’ dances, depending on the presence of infection. When the researchers compared the varroa-infested hives with uninfested ones, they found that the number of foraging dances was the same in the two groups, but the location of the dance floor differed. In the infected hives, the foragers were more likely to stay on the perimeter of the hive. In the uninfected hives, the foragers danced and waggled to their hearts’ content in the inner sanctum.

“The frequency of dances on the outermost frames is about 70% in infested colonies, compared with 10% in the uninfested colonies. So I would say that the probability of foragers being at the outer limits of the hive in infested colonies is seven times as likely as in uninfested colonies,” wrote Dr. Satta in an email.

Even one-day-old bees changed their behavior when detecting infection around them. They groomed each other more—which removed the mites—and fed and rubbed their antennae against nest-mates less. In other words, the presence of disease changed their social habits. If one-day-old honeybees can do it, so can we.

What Dogs Do and Don’t Understand

Our canine friends don’t get the meaning of our words without extra cues, research shows—but they do learn to anticipate what we say


By Susan Pinker


“Milo, leave it!” “Forest, come here right now!” “Louis, let’s go. I’ve got a conference call.” Most dog owners talk to their dogs and assume they understand what they say, and I’m no different. I tell 75-pound Otis to stop barking at dogs passing by, and he sometimes listens. I admit to using a high-pitched form of baby talk to narrate our walks, pointing out the forgotten tennis ball or the squirrel he shouldn’t chase, enunciating as if he were a human toddler.

But he’s not. We like to think that our dogs understand what we say, but the scientific evidence for true language comprehension in dogs is sparse. A few dogs are gifted. As a 2004 study in the journal Science showed, a border collie named Rico in Leipzig, Germany, could understand 200 words and execute precise verbal commands. But when all other cues are controlled for, the scientific consensus is that context, gesture and tone of voice signify much more to the average dog than human speech does.

“When it comes to lab conditions, it turns out that dogs are not good at word meanings,” said Marianna Boros, a postdoctoral researcher at Eötvös Loránd University in Hungary. Most need gestures and intonations to understand. She adds: “This is also true of commands like ‘sit.’”

Them’s fighting words for many dog lovers, but Dr. Boros knows whereof she speaks. Her research group is one of several at the Budapest school that specialize in canine cognition. The researchers haven’t found evidence for word comprehension in dogs per se. But they have discovered some of its neural scaffolding, such as a right-hemisphere bias for language processing in dogs’ brains, which is opposite to that of humans. They have also shown, using functional MRI scans of brain activity, that dogs know when a word and its intonation match.

Now they have proof that dogs can pick up on the boundaries separating words while listening to speech recorded without pauses and in a monotone, according to a new study led by Dr. Boros and Lilla Magyari, to be published in the journal Current Biology next month. Not only can dogs sense where a word begins and ends, but they can compute the probability that a certain syllable will appear next, much as our smartphones predict what we will tap next in a text or email.

To get access to such arcane canine data, the researchers used brain imaging on 37 dogs; 19 were tested by electroencephalogram and another 18 were trained to jump into the MRI scanner—which they did willingly and with tails wagging—to listen to speech samples.

The dogs’ brain responses showed that they could follow two rules: They note how frequently they hear two syllables together, and they compute how likely two particular syllables are to follow each other. This hasn’t been shown in nonhuman mammals before, though it has been shown in 8-month-old infants.

Dr. Boros’s study showed that dogs use some of the same neural hardware as babies do to detect word and syllable probabilities: the basal ganglia, which supports sequential and pattern learning, and the auditory cortex, one of the areas specialized for language.

While this doesn’t mean that dogs understand the meanings of words, it tells us that recognizing the building blocks of language is not unique to humans. “It suggests that the ability to segment speech is a general mammalian capacity” that may have evolved or been acquired by dogs while living alongside humans, said Dr. Boros.

In short, our babies, our smartphones—and even our dogs—can handily detect and predict what we might say or write next. As long as none of them actually finishes my sentences or tells me to “sit,” that’s fine with me.

Appeared in the November 20, 2021, print edition.

Storytelling Makes Hearts Beat As One

Research shows that listening to the same narrative leads our heart rates to rise and fall in unison


By Susan Pinker


A human heart is so much more than an organ. No one says they left their pancreas in San Francisco, for example, or that two kidneys beat as one. Yet most of us believe that two hearts can beat as one, and that the heart reveals our unedited emotions. Now there’s some evidence that such folk wisdom is true.

When people listen to the same story—each alone in their own home—their heart rates rise and fall in unison, according to a new study published last month in Cell Reports. “The fluctuations of our heart rates are not random,” said Lucas Parra, a professor of biomedical engineering at City College of New York and a senior author of the study. “It’s the story that drives the heart. There’s an explicit link between people’s heart rates and a narrative.”

This finding aligns with a mountain of research showing that our brains sync up when we interact in the same location, participate in the same activity, or simply agree with each other. The new study goes one step further; it tests whether our heart rates become synchronized while taking in the same narrative—even though we’re not in the same room nor even listening at the same time as other listeners.

The paper describes four small studies, each one with approximately 20 to 30 participants. In all four, subjects’ heart rates were monitored via EKG while they listened to or watched various types of stories, which included short audio segments of Jules Verne’s “20,000 Leagues Under the Sea,” excerpts from educational videos, and prerecorded children’s fables.

The goal was to see how much heart rate coordination there was among participants within the same study, all of whom had listened to the same type of content, though at different times. Did the peaks and valleys of their heart beats match up on the EKG? How faithfully do our hearts clock our mental lives—while we are reading a book, or listening to the radio or a podcast, or watching video content on our phones?

Marcel Proust wrote at the turn of the 20th century, “the heart does not lie.” The data tells us much the same: The heart’s connection to the brain is so tight that when we hear the same story, our heart rates sync up. The study found that subjects in the same group produced synchronized heart rate patterns that rose and fell at roughly the same times during the narrative. But if the subjects became distracted from the story by having to count backward, their hearts became desynchronized, and they remembered less of the story.

The researchers didn’t analyze which parts of the story changed an individual’s heart rate, only how well the patterns matched. But they also could tell that a participant whose heart rate was highly correlated with other participants remembered the content better. “Our explanation is that the story drives one’s attention,” said Prof. Parra.

The results are “heartwarming,” he added. “The novel finding is that heart rate correlation between subjects does not require them to actually be interacting, or even be in the same place. They can be listening to stories all alone at home, and their heart rate fluctuations will align with the story, and thus correlate with other listeners. It’s not the interaction between people but the story itself that does the trick.”

The point, he said, quoting another of the study’s authors, is that when we listen to the same radio program or watch a Netflix show, our hearts beat in unison, showing that “we’re not alone.”

Appeared in the October 9, 2021, print edition.

Fighting Crime With Home Renovations

Research shows that funding big repairs for a damaged house can affect the crime rate for an entire city block



By Susan Pinker


“It takes more than a hammer and nails to make a house a home,” sang the Staple Singers in 1965. An infusion of cash to keep it shipshape helps too, and that in turn, according to a new study, can improve the safety of a city block.

Published last month in the Journal of the American Medical Association’s Open Network, the study explored the relationship between home improvement grants and street crime in Philadelphia. It found a tight link between municipally funded house repairs and a drop in crime on those blocks with a city-funded overhauled home.

The streets of many of Philadelphia’s older neighborhoods are lined with graceful, colorfully painted Victorian row houses. But with more than 23% of the city’s residents living in poverty, many of these architectural gems have been showing the wear-and-tear of neglect for decades. Since 1995 the city government has been offering home-repair grants—up to $20,000 to low-income homeowners—to assist with costly maintenance jobs.

This Basic Systems Repair Program does not cover cosmetic upgrades, like fixing cracked windows or painting, but instead addresses the structural problems that beset old houses, such as leaky roofs, broken sewer lines, dangerous wiring and damaged plumbing. The goal is to prevent evictions and abandoned homes and thus to preempt broken neighborhoods. The program differs from the controversial “broken windows” theory of the 1980s, which suggested that eliminating surface signs of deterioration—while escalating the policing of minor offenses—would reduce serious crime; that approach did not feature investing in the community itself, or its homes.

“From the city’s perspective, there are multiple social costs when a house becomes uninhabitable and vacant,” said Vincent Reina, an associate professor of urban planning at the University of Pennsylvania and one of the study’s authors. “A vacant house becomes a vacant lot. Historically there has been a lack of investment in communities of color. So we asked, what does this small investment do?”

To find out, the research team merged data from 19,869 city blocks with each block’s crime data, focusing on the years from 2006 to 2013. Over a third of those blocks had received a home repair grant during that time. Blocks with at least one house repaired ultimately were compared with blocks where owners were on the waiting list, who formed a natural control group. Using census tract data, the researchers statistically controlled for demographic and economic variables, seasonal fluctuations in crime and “regression toward the mean”—which happens when extreme findings level off over time.

The results showed that blocks with a single house repair subsequently had a 21.9% reduction in crime compared with blocks with houses on the waiting list. Additional houses repaired on a block were linked with further drops in crime—up to a maximum of four houses, after which the curve flattened.

This was an observational study, so it remains unclear exactly why fixing the plumbing or roof of a home might lead to fewer homicides or thefts on that block. But Dr. Eugenia South, an assistant professor of emergency medicine at the University of Pennsylvania and the study’s lead author, has some ideas.

A maintained house might lead to a reduction in stress and a boost in mental health, which lead to a “cascade of good things” she said. “Perhaps it’s easier not to get mad at a neighbor’s barking dog or to connect with neighbors if there’s no mold in the house causing a child’s asthma.” In short, the study may be telling us in numbers what the Staple Singers told us in the next verse of their song: “Truth and trust” are what make a house a home.