Physicist explorer of datasets

Gut feeling for good ideas

Seated comfortably in his office in Lyngby, the professor appears at ease with the interview situation and answers questions by inching closer - sentence by sentence - to what sets him apart from the crowd. Because according to himself, he’s probably not the smartest person in the room or the best at machine learning.

So what is it that he brings to the table with his physicist background from the University of Copenhagen to the engineering-heavy computer science research environment at DTU Compute? He does not have a clear answer, so instead he thinks out loud:

“As a scientist, I have probably found a somewhat unusual niche that is more about breadth than depth. I believe that the typical path to success as a scientist is to have very deep knowledge of a single topic. I have a very wide range of interests and can keep up with conversations on many different topics. That offers you an opportunity to look across various areas and come up with out-of-the-box ideas,” says Sune Lehmann, and continues:

“Another strength of mine is probably that I’m good at spotting good ideas. I’m not necessarily the one coming up with the idea - it can also just be an idea that emerges from something a student said. But I have a gut feeling when something is promising. That’s the direction we’ll be pursuing. And I love conversation. I talk a lot with my students, my research colleagues, and all sorts of people. New ideas and new connections often emerge from those clashes of thoughts from different people,” says the professor, who originally studied philosophy, but chose physics because it offers the opportunity to observe the world rather than just talking about it, as he put it in a previous article about his journey into research.

Data explorer

The physicist’s urge to observe the world combined with an unbridled curiosity has thus become the 48-year-old professor’s driving force.

“Unlike today’s young people, my driving force is not to save the world.”

The sentence is followed by loud spontaneous laughter, after which the professor elaborates:

“Naturally, I want to help make the world a better place. But the aim of my research is not to solve all the world’s problems. My point of departure is actually a more humble one: I do the research I do because I want to find out how the world works.”

The raw material in Sune Lehmann’s research is data. He is a kind of data set explorer. Sune Lehmann discovered his passion for exploring data as a postdoc in the United States, where he collaborated with Laszlo Barabási - one of the world’s foremost network researchers.

“He was driven by the idea of exploring data from the world around us. It was completely different from the theory-focused physics I had grown up with. Today, I believe that when it comes to human behaviour, the patterns we can find ‘in the wild’ through data are often much richer and more interesting than the theories we humans can come up with. I realized that data is where we can really learn something new about the world.”

Sune Lehmann never begins his research with a question he wants answered. It’s actually the other way around, he says:

“I examine a data set and look for the kind of questions we can find a good answer to using that data. So I only pose the question when I see which answers the data set might provide.”

Distributed 1,000 smartphones

When Sune Lehmann came to DTU in 2010 as a researcher in the physics of complex networks, he had already made his first international media headlines. There had been a lot of interest in his research from his stays at Harvard University and Northeastern University, where Lehmann, using data from X (formerly Twitter), mapped Americans’ moods throughout the day and found that they are happier in the morning compared to later in the day, and that they are happier on the US West Coast than on the East Coast.

In Lyngby, Sune Lehmann hadn’t been on campus long before he laid the ground for new headlines by purchasing a total of 1,000 smartphones in 2012, which in the early 2010s were not household items. He distributed the phones to students in exchange for them donating their data to his research into human behaviour and networks.

The mobile phones gave the young assistant professor a groundbreaking dataset, enabling him and his colleagues to be among the first in the world to demonstrate how much the companies behind apps can actually monitor our activities via mobile phones. The dataset was also part of the discovery that we humans - young and old - move between a maximum of 25 locations. The number is pretty constant, and if we add a new location, one of the others is abandoned.

Last but not least, the dataset came in world-wide demand when the pandemic hit in 2020 and it became a matter of understanding people’s behaviour and contact points in order to limit the spread of COVID-19.

It is no coincidence that Sune Lehmann came up with the idea of tracking people’s mobility through smartphones. Or that his research in the US was based on data from the platform formerly known as Twitter.

“I became interested in smartphones and social media quite early on. Maybe that’s why I became one of the first to experience the negative effects of this technology and these apps. I personally noticed that the phone did not always affect me in a good way,” says Sune Lehmann.

Difficult to be present in the moment

The first signs that there is a downside to smartphones became clear in the mid-2010s, when he found it increasingly difficult to concentrate, to immerse himself in a task or a conversation, and generally being present in the moment. Failing focus was a key concern. At some point, he wondered if it was just an inevitable part of ageing, though he was barely 40 at the time.

“My children were small at the time, and I wanted to spend time with them. But it was difficult to slow down enough to sit down and read a book with them when your brain had gotten used to needing new information every ten seconds to be stimulated.”

This set two things in motion for the researcher: firstly, a new idea for his research, which led to the aforementioned realization of our decreasing collective attention, and secondly, the introduction of a much more conscious use of his smartphone and social media.

“There’s nothing wrong with the smartphone as such; the problem is our social media apps. They are designed to steal as much of our time and attention as possible, and if you don’t have a huge amount of self-discipline and are extremely conscious of your consumption of those apps, you will end up getting sucked in constantly. The same goes for emails. You can end up spending half your life responding to emails, unless you consciously choose to do something else,” says Sune Lehmann.

And the professor does this regularly - chooses to do something else. For instance, he prefers to talk to his students at a physical meeting once a week.

“So instead of each of them sending me ten emails with small questions, we talk it all through when we meet face to face.”

Eternal struggle to avoid being sucked in

Despite his conscious consumption of smart technologies, Sune Lehmann occasionally gives in to temptation and suddenly finds himself answering loads of emails. Just then, a ding is heard from the professor’s smartphone. He glances at it.

“It’s just a calendar notification letting me know we have ten minutes until my next meeting,” he says and elaborates: “The calendar is the only app allowed to make a sound on my phone. And calls from my family.”

Yet he still experiences it as a struggle to find a space for peace, contemplation, and quality in a world that has been designed for the opposite.

“The most important thing I have discovered is that if you understand that staying focused and not getting sucked into these technologies is a constant battle, it’s easier to win that battle than if you have a blue-eyed belief that it’s a quick fix.”

Award for research environment

The desire for immersion and quality in both his research and his relationships is also reflected in Sune Lehmann’s management of the Social Complexity Lab research group - a management he shares with Laura Alessandretti, Associate Professor at DTU Compute. In the summer of 2023, Social Complexity Lab won Research Environment of the Year, which is awarded by the Danish Young Academy. The research group was chosen from 29 nominated environments.

The secret is not that Sune Lehmann has read hundreds of management books. He doesn’t base his work as a leader on long-winded theories or fancy diagrams. When summing up his management style, this is what he says:

“I really just want to be a decent and honest person. My goal is to always be able to substantiate anything I do or say. And from there, it’s just about doing work to the best of our abilities.”

However, he has, together with his co-leader Laura Alessandretti, created a structure around the researchers in the Social Complexity Lab that allows them to divide their time between joint events and free time, which can, for instance, be used to immerse themselves in their work.

In addition, Sune Lehmann has chosen Thursday as their weekly meet-up day. Here, he can look his employees in the eye and talk to them about their projects and everything in between, as a way to minimize the number of emails.

Room for fun - and mistakes

And last but not least, they meet for joint lunches on Fridays, something that has become a priority for the entire group.

“We relax and have a good time - followed by a group meeting where everyone gets to speak. You choose what you want to share with the others. It is usually something from your professional life, but it can also be something personal. It’s a space where there is room for both. After all, we’re not just scientists, we’re also human,” says Sune Lehmann, who likes to take the lead in telling about his own experiences and mistakes to encourage others to do the same.

The fact that the research group values both their academic competency and their private lives is also evident from the Social Complexity Lab’s website. A little further down the page, it says:

“Finally, if you wonder why the website is so minimal (and terrible), it’s because we’re busy writing papers or perfecting work/life balance instead of making fancy websites.”

There you go. It can’t be said much clearer than that: It is about maintaining focus on what’s important.