Dunbar's number is a popular estimate for the maximum size of social groups. But new research suggests that it's a fictitious number based on flimsy data and bad theory.
- A team of researchers recalculated Dunbar's number using his original methods and better data.
- Their estimates were as high as 520 and were stretched over a wide enough range as to be nearly useless.
- The authors suggest that the method used to calculate the number of friends a person can have is also theoretically unsound.
Since 1992, people have been talking about "Dunbar's number," the supposed upper limit of the number of people with whom a person can maintain stable social relationships. Named for British anthropologist Robin Dunbar, its value, rounded from 148 to 150, has permeated both professional and popular culture.
The Swedish taxation authority keeps offices under 150 people as a result of it, and the standard facilities of the W. L. Gore and Associates company are based around the concept. Dunbar's number was cited in Malcolm Gladwell's bestselling book Tipping Point, and it also has a fair amount of academic influence, the original paper having been cited 2,500 times.
It's also probably wrong.
Despite its fame, Dunbar's number has always been controversial. A new study out of Sweden and published in the journal Biology Letters suggests it might be both theoretically and empirically unsound.
Getting to 150
Less well known than the value of Dunbar's number is how he came up with it. The value of 150 is determined by looking at the ratio between the size of the neocortex in primates and the average size of groups they form. These ratios were then applied to data on the human brain, and the average value of roughly 150 relationships was determined.
The point of this study isn't to replace Dunbar's number but to dismiss the notion that such a number can be determined in the first place.
However, this number has always been the subject of debate. An alternative value based on empirical studies of American social groups is a much higher 291, nearly double that of Dunbar, and suggests that the median social network has 231 people in it. That value wasn't calculated by crunching other numbers; it kept coming up again and again when the authors of that study looked at the professional and social networks cultivated by different groups of people.
Yet, even in the face of critics and new studies, Dunbar's number always managed to hang on in popular and academic discourse. That is where this latest study comes in.
A new study with old methods but better data
In the new study, the researchers did similar calculations as Dunbar but with updated information on the size of monkey brains and social networks. While their average human group size was below Dunbar's estimate, the upper boundary of the 95 percent confidence interval ranged between 2 and 520 people depending on what methods were used. Nearly every method gave a range of possibilities with a maximum value higher than 150.
When the authors applied Dunbar's exact same methods from 1992 to their new data, they got an average group size of 69 people — but a 95% confidence interval between roughly 5 and 292. This is far too wide a range to be of any use.
Additionally, the authors discuss the flimsy nature of the theory behind Dunbar's number. Human brains often work differently than those of our nearest evolutionary cousins, as evidenced by our ability to create things like, "Stockholm, symphonies, and science." The idea that we would process social information exactly like other apes do is a bold and largely unsubstantiated claim.
They quote a study by Jan De Ruiter and their rejection of the idea that the ratio between monkey neocortex size and group composition can be carried over to humans:
"Dunbar's assumption that the evolution of human brain physiology corresponds with a limit in our capacity to maintain relationships ignores the cultural mechanisms, practices, and social structures that humans develop to counter potential deficiencies"
So, is there a new Dunbar number?
The point of this study isn't to replace Dunbar's number but to dismiss the notion that such a number can be determined in the first place. The authors go so far as to end their paper with:
"It is our hope, though perhaps futile, that this study will put an end to the use of 'Dunbar's number' within science and in popular media. 'Dunbar's number' is a concept with limited theoretical foundation lacking empirical support."
While this study may not be the death of Dunbar's number — after all, less empirically sound ideas have endured much longer — it may be the foundation for new attempts to determine how large our meaningful and stable social groups can be.
Scientists ripped up kids' drawings. This is what they learned about relationships.
- Forgiveness as a cultural act linked to religion and philosophy dates back centuries, but studies focused on the science of apologies, morality, and relationships are fairly new. As Amrisha Vaish explains, causing harm, showing remorse, and feeling concern for others are things children pay attention to, even in their first year of life.
- In a series of experiments, adults ripped children's artworks and either showed remorse or showed neutrality. They found that remorse really mattered. "Here we see what [the kids] really care about is that the transgressor shows their commitment to them, to the relationship," Vaish says. "And they will seek that person out over even an in-group member."
- As a highly social species, cooperation is vital to humans. Learning what factors make or break those social bonds can help communities, teams, and partners work together to meet challenges and survive.
Experts plead with Americans to keep gatherings limited this Thanksgiving, while families devise new ways to celebrate the holidays.
Like any holiday, Thanksgiving has always had challenges mixed in with the fun. There are maddening travel logistics, crafting a dinner to meet everyone's dietary needs, avoiding your uncle's ceaseless politic-baiting conversation starters, and, of course, finding someone who can muscle through the post-dinner slumber to tackle the dishes. But this year, families must face an unprecedented challenge: managing family expectations and safety during the pandemic.
After 2020's contentious news cycle and a record-breaking number of disasters, Americans want a dollop of normality to go along with their pumpkin pie. Unfortunately, this desire has grown in tandem with COVID-19 cases. As of this writing, the United States is climbing its third pandemic peak and has endured more than 11 million cases and nearly 250,000 deaths (more than any other country). According to Johns Hopkins data, last week saw the U.S.'s highest seven-day average at 78,738 cases per day.
"We're at a point where the epidemic is accelerating across the country. We're right at the beginning of the steep part of the epidemic curve," Dr. Scott Gottlieb, former U.S. Food and Drug Administration commissioner, said on CNBC. He added, "You'll see cases start to accelerate in the coming weeks. December's probably going to be the toughest month."
The experts agree
A graph showing confirmed coronavirus cases from Jan. 3 to Nov. 18, 2020. The third, current peak is the largest so far.
Dr. Gottlieb is just one of many experts who worry that Thanksgiving trips and gatherings will bolster the growth of COVID cases in America. Dr. James Phillips, chief of disaster medicine at George Washington University Hospital, told CNN that he expects cases to spike after Thanksgiving, further stressing the health care system and prompting harsher restrictions. If Americans do not learn from Thanksgiving, he forecasts another spike at Christmas.
Dr. Iahn Gonsenhauser, chief quality and patient safety officer at The Ohio State University Wexner Medical Center, concurs. As he told Live Science: "Most experts would agree that we're expecting to see a spike after Thanksgiving and that's a spike on top of already very discouraging and very scary numbers. By far the safest choice that anybody can make this Thanksgiving holiday and likely stretching into the other winter holidays that are coming up is to host your celebration virtually."
While many Americans may recognize Dr. Gonsenhauser's advice as sage, it's equally unwelcomed. Pandemic fatigue is depleting the nation's willpower and clouding its judgment. Add to that a longing to see family and friends—many of which we may have been separated from for close to a year—and it's easy to see why so many Americans are heading home for the holidays.
According to a TripAdvisor survey, 56 percent of Americans plan to travel this Thanksgiving—less than previous years but a substantial amount nonetheless. Airlines are adding more flights to meet the demand, and more people in airports will increase the likelihood of transmission. Many other Americans will travel by car, popularly seen as the safer option but one that still increases one's risk of exposure at restaurants, gas stations, and public restrooms.
In response, governors have instated a patchwork of restrictions. They've closed nonessential indoor businesses, limited restaurants to pick-up orders, and made face masks a requirement when out and about. Hospitals have also geared up for an influx of new patients while facing their own holiday challenges. Many are already caring for large swaths of COVID patients while the winter weather is making physical-distancing tactics, such as outdoor tents, more difficult to manage.
"We don't really want to see mamaw at Thanksgiving and bury her by Christmas," Dr. Mark Horne, president of the Mississippi State Medical Association, told the Associated Press. "It's going to happen. You're going to say 'Hi' at Thanksgiving, 'It was so great to see you,' and you're going to either be visiting by FaceTime in the ICU or planning a small funeral before Christmas."
To grandmother's house we go?
Even while governors and experts pleaded with families to limit Thanksgiving gatherings to individual households, there has been no uniform, country-wide restrictions put in place. As such, every family must perform a risk calculation to decide how to spend Thanksgiving.
"[G]iven the fluid and dynamic nature of what's going on right now in the spread and the uptick of infections, I think people should be very careful and prudent about social gatherings, particularly when members of the family might be at a risk because of their age or their underlying condition," Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Disease, said on CBS Evening News.
He added, "When you're talking about relatives that are getting on a plane, being exposed in an airport, being exposed in a plane, then walk in the door and say 'Happy Thanksgiving' — that you have to be careful about."
To help families make their decisions, the Centers for Disease Control and Prevention (CDC) has released Thanksgiving considerations to supplement safety alongside local rules and regulations. The agency lists several factors to consider in any risk calculation. These include local levels of COVID-19, potential travel exposure, the number of people attending, the health risks of those attendees, and the duration of the gathering as well as its location.
If people from outside the household will attend, the CDC recommends the following actions to increase safety and limit viral transmission:
- Ensure everyone wears a mask when not eating or drinking;
- Keep people who do not live together at least 6 feet apart;
- Have people bring their own food, drinks, utensils, etc. No potluck-style dinners;
- Host the gathering outdoors or increase indoor ventilation;
- Keep music levels down to prevent shouting or speaking too loudly;
- Encourage good handwashing;
- Clean and disinfect commonly touched surfaces often.
You can find more information on the CDC's Holidays website. It's also worth noting that a negative result on a COVID-19 test is no guarantee of safety. People can harbor the virus, become infectious to others, show no symptoms, and still render a false positive several days after their initial infection.
Staying home for the holidays
For families staying physically distanced, there remains the question of how to celebrate Thanksgiving this year. 2020's standard answer has been the Skype or Zoom call. Certainly an option, but one that should be spiced up for the holiday meal.
You can, for example, integrate your preferred telecommunication app can into shared experiences. Family members can work meal prep together or teach each other their signature dishes. Activities like crafts, decorating, and thankfulness trees can be coordinated by the kids and shared with the family simultaneously. You can cook up the same meal, light the same scented candles, and listen to the same music to create a common sensual environment.
You can also find telecommunication apps designed to be used alongside specific activities. Discord is a favorite among gamers for video games. Even if battle royales aren't your family's speed, it works perfectly well for board games, and your family's favorite likely has a digital version available. Similarly, Netflix's Teleparty provides an online space to watch and chat about movies together. If Black Friday was your family's bonding tradition, try scouring for the savings together online and share a cocktail afterward to toast a successful shop. There is also the platform Gather, which allows for proximity video chatting in a customizable 2D world.
If your family wishes to disconnect from the binary realm, try beginning a new holiday tradition this Thanksgiving. You can write holiday letters to distant family members. We're talking physical letters, which preliminary research suggests has the salubrious bonus of reducing stress and anxiety for the writer. You can create holiday care packages for friends. And this year especially, the holiday card and photobook traditions will be more appreciated than ever. If you're in a time crunch, emails or texts are also nice.
For most families, Thanksgiving in 2020 will be unlike any other and will be, for better or worse, one to remember. Thankfully, there are ways to stay safe and healthy—and help others do so, too—while still connecting with loved ones in a meaningful way.
Building a personal connection with students can counteract some negative side effects of remote learning.
- Not being able to engage with students in-person due to the pandemic has presented several new challenges for educators, both technical and social. Digital tools have changed the way we all think about learning, but George Couros argues that more needs to be done to make up for what has been lost during "emergency remote teaching."
- One interesting way he has seen to bridge that gap and strengthen teacher-student and student-student relationships is through an event called Identity Day. Giving students the opportunity to share something they are passionate about makes them feel more connected and gets them involved in their education.
- "My hope is that we take these skills and these abilities we're developing through this process and we actually become so much better for our kids when we get back to our face-to-face setting," Couros says. He adds that while no one can predict the future, we can all do our part to adapt to it.
This video is part of Z 17 Collective's Future of Learning series, which asks education thought leaders what learning can and should look like in the midst and wake of the coronavirus pandemic.
This is one of countless studies that prove the positive impact of social connection and intimacy while highlighting the negative impact of isolation and separation.
- New research, led by behavioral neuroscience assistant professor Zoe Donaldson explores what drives our mammalian instinct to create lasting bonds - and what exactly happens when we are apart from people we share those bonds with.
- Studying prairie voles (who fall under the 3-5% of mammals who, along with humans, are monogamous), Donaldson and her team discovered a unique set of cluster cells that light up when reunited with a mate after a period of separation.
- This study is just the tip of new developing research that could lead to groundbreaking new therapies for individuals who struggle with these types of connections, including people with autism, people who struggle with mood disorders, etc.
Assistant professor of behavioral neuroscience at CU Boulder Zoe Donaldson has recently led a year-long study of prairie voles, who are in the 3-5% of mammals (along with humans) who tend to mate for life.
"In order to maintain relationships over time, there has to be some motivation to be with that person when you are away from them. Ours is the first paper to pinpoint the potential neural basis for that motivation to reunite," explains Donaldson.
What drives the mammalian instinct to create lasting bonds? This was the question Donaldson and her team sought out an answer for. And not an answer based on philosophy or emotion, but an answer based on neuroscience and hard-proof.
This research ground lead to new therapies for individuals who struggle with this kind of emotional connection.
Photo by torook on Shutterstock
Donaldson and her team used tiny cameras and a new technology called in-vivo-calcium imaging to analyze the brains of prairie voles at three separate times:
- During their first encounter with another vole
- Three days after mating with another vole
- 20 days after living in the same area as the mate
When the voles were together in the same area, their brains looked and reacted the same way. However, after separating the voles, it was discovered that a unique cluster of cells in the nucleus accumbens fired up when they were reunited.
In fact, the study proved that the longer the voles had been paired before being separated, the closer their bond became and the glowing cluster that lit up became stronger during their reunion.
It's interesting to note that a whole different cluster of cells lit up upon them being introduced to a stranger vole, suggesting that these specific cells may actually be there for the purpose of forming and maintaining bonds with others.
This study confirms that monogamous mammals (voles and humans alike) are very uniquely hard-wired to mate with others. We have a unique biological drive that urges us to reunite with people we care for, and this drive can be one of the reasons we fall under the 3-5% of mammals that seek out monogamy.
What does this mean for the future of human behavior studies?
As far as research goes, this is quite groundbreaking - as this could potentially give us insight into various kinds of therapies for individuals who are autistic or individuals who struggle with severe depression and/or other disorders that make these kinds of emotional connections difficult.
There is still much to learn about these specific series of events that happens when we're reunited with a mate after a period of separation. For example, it's unclear if this "neuronal code", so to speak, is associated with emotion in humans the same way it is associated with desire in voles.
According to Donaldson, the research in this department is only just beginning, and the definitive outcome of this study is that mammals are quite literally hardwired to be monogamous mammals.
Social connection and intimacy is essential to our growth and development
This isn't the first time a study like this has been conducted, even though this particular study has unveiled new neuronal clusters that had not been previously accounted for.
There have been many other studies of mammals (from small rodents all the way up to human beings) that suggest we are not only hardwired to seek out intimate connections through monogamy, but that we are also extremely and profoundly shaped by (and perhaps even dependent upon) the experiences we have with those mates.
Brene Brown, a University of Houston Graduate College of Social Work (who specializes in social connection), explains:
"A deep sense of love and belonging is an irresistible need of all people. We are biologically, cognitively, physically, and spiritually wired to love, to be loved, and to belong. When those needs aren't met, we don't function as we were meant to."
This idea is backed up by countless studies, including Dr. Helen Fischer's revolutionary study back in 2005, which included the very first fMRI images of "the brain in love".
This study concluded that the human brain doesn't just work to amplify positive emotions when we experience romantic love, but that the neural pathways responsible for negative emotions (such as fear and anxiety) are actually deactivated.