Robin Dunbar, an anthropologist from England, has been studying and refining his theory on how large human networks can realistically get. Graphic by Miguel Tovar/University of Houston

You go to conferences; you network; you collaborate — all researchers and academics do. But do you need more than 150 contacts? Linkedin, Facebook, Twitter — all of these platforms open us up to the possibility of thousands of acquaintances, though fewer we would refer to as "friends."

Studying the primate brain

Robin Dunbar, an anthropologist from England, has been studying and refining his theory of the "Dunbar number" for 30 years. Dunbar became convinced that there was a ratio between brain sizes and group sizes through his studies of primates. "This ratio was mapped out using neuroimaging and observation of time spent on grooming, an important social behavior of primates. Dunbar concluded that the size, relative to the body, of the neocortex – the part of the brain associated with cognition and language – is linked to the size of a cohesive social group," wrote Christine Ro in a 2019 BBC.com Future article.

After the group reached approximately 150, it collapsed.

Your network

Is it true that humans based on their brain, and especially pre-frontal lobe size, are only able to connect in an intimate manner with around 150 other individuals? Defined as someone you would make plans to have a drink or coffee with if you bumped into them randomly on the street, Dunbar's claim is that it seems to be a consistent theme throughout history. Says the BBC: "This rule of 150 remains true for early hunter-gatherer societies as well as a surprising array of modern groupings: offices, communes, factories, residential campsites, military organizations, 11th Century English villages, even Christmas card lists."

The Dunbar number decreases by a "rule of three" where the next step down is the number 50 – those you consider "friends." Then about 15 in a closely knit circle, and four to six only in our familial or closest friend contacts.

Social media and COVID-19

"What determines these layers in real life, in the face-to-face world… is the frequency at which you see people," says Dunbar. "You're having to make a decision every day about how you invest what time you have available for social interaction, and that's limited." So, social media and COVID would seem to be game-changers for this theory.

Dunbar went on to study the process of "grooming" and light touch with astonishing results, which you can read about in the New Yorker. Basically, if a person has a face-to-face encounter with a friend, they are consequently able to withstand unpleasantness right afterwards (their hands stuck into a bucket of ice, for instance!) at a much higher rate.

"It makes sense that there's a finite number of friends most individuals can have," wrote Ro. "What's less clear is whether that capacity is being expanded, or contracted, by the ever-shifting ways people interact online …'It's extremely hard to cry on a virtual shoulder,' Dunbar deadpans."

And how has COVID changed Dunbar's theory? "While our culture has encouraged us to accumulate friends, both on- and offline, like points, the pandemic has laid bare the distinction between quantity and quality of connections," said a New York Times article. "There are those we've longed to see and those it's been a relief not to see."

The Big Idea

Many try to debunk Dunbar's number, by saying that primate and human brains differ and that the calculations are off. Robin Dunbar defends his theory thirty years after first proposing it in The Conversation.

The number of people you can just recognize according to Dunbar, is about 1,500, so you might want to keep that in mind if you are an extrovert and have an incredibly large network of collaborators – both online and offline.

University of Houston's central research department, the Division of Research, has about 100 members. But, your Linkedin network — check the number and see what it sits at. And if it's 600, ask yourself: do you really need that many contacts?

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This article originally appeared on the University of Houston's The Big Idea. Sarah Hill, the author of this piece, is the communications manager for the UH Division of Research.

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8+ can't-miss Houston business and innovation events in April

where to be

Editor’s note: Houston's weeklong innovation festival kicks off April, followed by Rice University's globally recognized pitch competition returning for its 26th year. Plus, find coworking pop-ups, industry meetups, pitch battles and even a crawfish boil on the calendar. Here’s what not to miss and how to register. Please note: this article might be updated to add more events.

March 30-April 4 — H-Town Roundup

Celebrate innovation, entrepreneurship and collaboration at Houston Exponential's sixth-annual H-Town Roundup. During the free event series, previously known as Houston Tech Rodeo, attendees can expect insightful talks, workshops and networking events at venues across the city.

This event began March 30. Register here.

April 2 — Industrious Coworking Day

Enjoy a complimentary day of cowering at Industrious and network with professionals at the Ion. Breakfast, snacks, wifi and workspace tours are included. Following the cowering day, Industrious will host happy hour at Second Draught from 4-6 p.m.

This event is Thursday, April 2, from 8:30 a.m.-5 p.m. at the Ion. Register here.

April 2 — Technology Summit for Women

The fourth annual Women in Tech Cummil will feature speakers across three core tracks: Transformation + Digital strategy, Cyber + Risk + Resilience, and AI in Practice. Pearl Chu, director of technical domains and university relations at SLB, will give the opening remarks. Other panelists come from CenterPoint Energy, BP, Technip Energies and other leading companies.

This event is Thursday, April 2, from 2-5 p.m. at the Ion. Register here.

April 8 — Veterans Business Battle

Hear pitches from veterans and entrepreneurs as they compete for more than $10 million in investments at Rice Businesses' 12th annual Veterans Business Battle. This year, the two-day event will also feature a Small Business Expo, which invites Houston-based, veteran-owned businesses to participate in education, networking and the opportunity to showcase their business. Moonshots Capital and Mercury Fund will also host a fireside chat.

This event begins Wednesday, April 8, at 11 a.m. at the Ion. Click here to register.

April 9-11 — Rice Business Plan Competition

The Rice Alliance for Technology and Entrepreneurship will host the 26th annual Rice Business Plan Competition this month. Forty-two student-led teams from around the world, including one team from Rice, will present their plans before more than 300 angel, venture capital, and corporate investors to compete for more than $1 million in prizes.

This event begins Thursday, April 9. Find more information here.

April 10 — BioHouston Chili Cookoff

Connect with Houston's life sciences community at BioHouston's 21st annual chili cookout. This event is geared toward startup founders, researchers and industry veterans alike.

This event is Friday, April 10, from noon-4 p.m. at Bayou City Event Center. Register here.

April 14 — Mercury Fund Day at the Ion: Agentic Commerce

Don’t miss the latest installment of Mercury Fund Day at the Ion, previously known as Software Day. The recurring monthly event features office hours (by application), a keynote and networking opportunities. This month's topic focuses on agentic commerce.

This event is Tuesday, April 14, from 3:30-7 p.m. at the Ion. Register here.

April 19 – UH Energy Industry Crawfish Boil

Head to the UH Cullen College of Engineering Green Space for the 35th annual UH Energy Industry Crawfish Boil. The event will include a student showcase, STEM activities, a kids zone, live music, networking and, of course, crawfish. Proceeds from the event will support the multidisciplinary capstone fund that aims to increase professional readiness for Cullen College engineering and technology students.

This event is Sunday, April 19, from 1-5 p.m. at the Cullen College of Engineering Green Space. Find more information here.

April 24 — Rice Business Healthcare Conference

Leading experts, innovators and the next generation of healthcare leaders will converge at the Rice Business Healthcare Conference. Hosted by the Rice Business Healthcare Association, the conference will explore AI's potential impact on the sector.

This event is Friday, April 24, from 8 a.m.-2 p.m. at McNair Hall on Rice University's campus. Find more information here.

Houston unicorn closes $421M to fuel first phase of flagship energy project

Heating Up

Houston geothermal unicorn Fervo Energy has closed $421 million in non-recourse debt financing for the first phase of its flagship Cape Station project in Beaver County, Utah.

Fervo believes Cape Station can meet the needs of surging power demand from data centers, domestic manufacturing and an energy market aiming to use clean and reliable power. According to the company, Cape Station will begin delivering its first power to the grid this year and is expected to reach approximately 100 megwatts of operating capacity by early 2027. Fervo added that it plans to scale to 500 megawatts.

The $421 million financing package includes a $309 million construction-to-term loan, a $61 million tax credit bridge loan, and a $51 million letter of credit facility. The facilities will fund the remaining construction costs for the first phase of Cape Station, and will also support the project’s counterparty credit support requirements.

Coordinating lead arrangers include Barclays, BBVA, HSBC, MUFG, RBC and Société Générale, with additional participation from Bank of America, J.P. Morgan and Sumitomo Mitsui Trust Bank, Limited, New York Branch.

“As demand for firm, clean, affordable power accelerates, EGS (Enhanced Geothermal Systems) is set to become a core energy asset class for infrastructure lenders,” Sean Pollock, managing director, project Finance at RBC Capital Markets, said in a news release. “Fervo is pioneering this step change with Cape Station, a vital contribution to American energy security that RBC is proud to support.”

The oversubscribed financing marks Cape Station’s shift from early-stage and bridge funding to a long-term, non-recourse capital structure, according to the news release.

“Non-recourse financing has historically been considered out of reach for first-of-a-kind projects,” David Ulrey, CFO of Fervo Energy, said in a news release. “Cape Station disrupts that narrative. With proven oil and gas technology paired with AI-enabled drilling and exploration, robust commercial offtake, operational consistency, and an unrelenting focus on health and safety, we have shown that EGS is a highly bankable asset class.”

Fervo continues to be one of the top-funded startups in the Houston area. The company has raised about $1.5 billion prior to the latest $421 million. It also closed a $462 million Series E in December.

According to Axios Pro, Fervo filed for an IPO that would value the company between $2 billion and $3 billion in January.

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This article first appeared on EnergyCapitalHTX.com.

Houston food giant Sysco to acquire competitor in $29 billion deal

Mergers & Acquisitions

Sysco, the nation's largest food distributor, will acquire supplier Restaurant Depot in a deal worth more than $29 billion.

The acquisition would create a closer link between Sysco and its customers that right now turn to Restaurant Depot for supplies needed quickly in an industry segment known as “cash-and-carry wholesale.”

Sysco, based in Houston, serves more than 700,000 restaurants, hospitals, schools, and hotels, supplying them with everything from butter and eggs to napkins. Those goods are typically acquired ahead of time based on how much traffic that restaurants typically see.

Restaurant Depot offers memberships to mom-and-pop restaurants and other businesses, giving them access to warehouses stocked with supplies for when they run short of what they've purchased from suppliers like Sysco.

It is a fast growing and high-margin segment that will likely mean thousands of restaurants will rely increasingly on Sysco for day-to-day needs.

Restaurant Depot shareholders will receive $21.6 billion in cash and 91.5 million Sysco shares. Based on Sysco’s closing share price of $81.80 as of March 27, 2026, the deal has an enterprise value of about $29.1 billion.

Restaurant Depot was founded in Brooklyn in 1976. The family-run business then known as Jetro Restaurant Depot, has become the nation's largest cash-and-carry wholesaler.

The boards of both companies have approved the acquisition, but it would still need regulatory approval.

Shares of Sysco Corp. tumbled 13% Monday to $71.26, an initial decline some industry analysts expected given the cost of the deal.