What brought you to neuroaesthetics?

Dr. Chatterjee: I’m trained as a neurologist. I saw patients for 40 years before retiring from clinical practice about two years ago. My research life was embedded in cognitive neuroscience, which basically asks the question of how our mind is implemented in the brain.

Where I started was to study how people with focal brain damage are affected in their thinking and interactions with the world. It’s a reverse engineering problem: if things break down in principled ways, you work backwards to understand the original characteristics of systems.

Around 1999, Penn was starting a Center for Cognitive Neuroscience, and I was recruited to come back, having been there as a medical student. This transition gave me an opportunity to reevaluate my research program. I thought that aesthetics—something I had always personally been interested in—seemed like a fundamental aspect of what humans are preoccupied with and affected by. At that time, there was virtually nothing written about or neuroscience work done in this area. That’s how it started.

You developed the Neuroarchitectural Triad to explain how people experience space. Walk us through it.

In our research, the Triad accounts for a lot of the variability in how people respond to the built environment.

Coherence is how organized and legible a space is. When you look at a space, do you have a clear sense of where you need to go and how you navigate through it?

Fascination has to do with informational density and complexity. Is it the kind of place people wish to explore? Does it generate interest? Do you feel curious about what’s happening in this space?

The third one is hominess, and that has received the least attention. It may be the most important one for interior designers. Does a person in that space feel that they’re at home? Does it feel natural? Do they feel as if they are in their skin and completely comfortable?

How does the balance of those three change depending on the type of space?

Start with the function of the space and the people in it. If you’re designing an airport, coherence is key. You want the space to be coherent above all. You might want some fascination, but what I personally find annoying is the duty-free section where you get in and can’t figure out how to get out. Those places are high in fascination. They’re designed to trap you in there to explore, even when you need to get to your gate.

One thing I appreciate is the trend to include more artwork and exhibits in airports. If you’re not in a rush and you’re between gates, you can stop and look at what local artists are doing.

If you’re designing a sports stadium, you want high fascination. You want people to be aroused and excited.

If there’s one piece of design that gets the least attention in America, it’s the soundscape. There’s a pernicious assault on our physiology from HVAC systems, construction and all the mechanical sounds that envelop us. Hospitals are among the worst places for this—the sounds in them are horrible.

Not everyone experiences space the same way. How should designers think about individual differences?

Individual differences are really important. My experience is that most architects and designers do not even think to ask the question. So kudos to you for not only asking it but conducting work in this area.

We have found that people on the autism spectrum, for example, don’t respond the same way as neurotypical people in environments that most regard as fascinating. We think that’s partly because they find the space overwhelming. Instead of evoking an approach response, there can be a repulsion. That’s not to say make it boring, but fascination tends to be associated with arousal, and you can ask the question: under what arousal conditions are people most comfortable?

One other piece—and there’s no judgment here—is that we have found that designers and architects tend to value coherence more than everyday folks. Sometimes there can be a disconnect between the designers and the people for whom the spaces are being designed. It could very well be that the users come around to thinking the architects’ view of coherence was a good one. But at the very least, recognizing that the way these components are weighted can be different encourages ongoing communication.

You also developed the Aesthetic Triad. How does that framework relate to the built environment?

The Aesthetic Triad is the idea that our aesthetic experiences are informed by three large-scale neural systems. The first concerns our sensory and motor processing. The second has to do with our emotional systems. When we talk about beauty, we often default to pleasure and reward. But our emotional systems are more nuanced than that—there’s no one-emotion-fits-all. The third is semantics and knowledge, which is what we all bring to bear in our experiences. That can be based on our level of education, our prior experience with art and architecture, the culture we’re in, how old we are and what time in history we’re living in.

In the built environment, all three are in play. Most of our sensory systems are very similar to each other. Our emotional systems broadly tend to be similar. Where it starts to vary is in the words we use to describe emotions. But once you get to semantics and knowledge, that’s where people really diverge. The great art historian Ernst Gombrich talked about the “beholder’s share.” What are you bringing to the table before you’ve encountered anything?

Your work explores a basic question: what is beauty? What have you learned?

Beauty is one of those things that everybody has a feel for, and it becomes hard to define. At its simplest, beauty is linked to pleasure. It can be as simple as a little sugar on your tongue. You wouldn’t call that especially beautiful, but those are the elemental features that build into a beautiful meal or a larger experience.

It’s important to ask: beauty of what? We use the way the brain carves out the world as our organizing principle: people, places and things. We react to the beauty of faces. We react to the beauty of places, both natural landscapes and the built environment. And to things like art, which in some ways poses a real mystery about why we care about a bunch of paint slathered on a canvas.

There is more consistency across people when it comes to faces and landscapes, and more variability with human artifacts like the built environment and art. One study looked at how architecture graduate students responded to buildings compared to students without that expertise. In the architecture students, in addition to reward areas, there was also activity within the medial temporal cortex, which encodes memory and knowledge. People with expertise in this domain were engaging their knowledge systems when they had a reward response, in a way that someone without training in architecture didn’t. It’s a roundabout way to say that beauty depends on what is being experienced and who is doing the experiencing.

How quickly does the brain make these judgments about a space?

In my lab, we don’t do this kind of work, but EEG research has reported an early and a late beauty response. The early one is on the order of 250 to 300 milliseconds. That’s that instant response—a quick appraisal that might lead to a decision. And then at around 800 to 1,250 milliseconds, still less than two seconds, there’s another wave where other systems are catching up.

What are you working on now?

I think of the mission of my center in two parts: understanding the fundamental nature of aesthetic experiences, and why they matter? The “why do they matter” becomes the application. I’ll mention two applications: one relevant to urban design and the other to interior design.

The urban design question is, what is the role of public art in the city’s landscape? Philadelphia has the largest open-air, accessible art gallery in the country. There are between 4,000 and 5,000 public murals across the city. We have done work suggesting that when people engage with murals in a guided way, it actually changes their perception of those neighborhoods. My sense is that urban designers have keyed into the importance of nature and green spaces and not enough into the role of public art and how it can bind communities.

On the interior side, there’s this question that is now popular in design circles about biophilic design. And if you do a deep dive into the academic literature, there are some very good ideas, but actual solid evidence of its beneficial effects is harder to come by.

We find that people do seem to like elements of nature in the interior, and people like the imprint of human order in nature. One way to think about this is that the building is like a semi-permeable membrane. We want some nature brought in and some of our order sent out. That’s a sweet spot where people live.

One of the big ideas around biophilic design has been stress reduction theory—that these kinds of environments reduce stress. We decided to do a real-world test of this. There is a behavioral health facility treating substance use and mental health challenges in La Plata, Maryland, about half an hour from D.C. We helped with the design, especially the refresh rooms designed with biophilic principles.

When we do field studies, we don’t have the same level of control as in the laboratory, so we compromise on purity. But we get a big boost in ecological validity. I mean, if our laboratory work doesn’t apply in the real world, who cares?

We haven’t analyzed the data yet, but there are some anecdotes. And though anecdotes do not make science, they do make for good stories. What people tell us is that some of the visitors take off their shoes as soon as they go in. And this is not a culture where that is a common practice. The fact that they’re taking off their shoes says something about them feeling safe and comfortable. We had one military veteran who has a very hard time sleeping. He’s been in there twice now, and within 10 minutes, he’s fallen asleep on the couch. As an anecdote, that gives us some optimism that maybe this design stuff works.

Anjan Chatterjee, MD, FAAN, is a Professor of Neurology, Psychology and Architecture at the University of Pennsylvania and the founding director of the Penn Center for Neuroaesthetics. His 2026 essay “Neuroaesthetics” in the MIT Press Open Encyclopedia of Cognitive Science offers a concise overview of the field’s key ideas and themes. To learn more about the Center’s research, visit neuroaesthetics.med.upenn.edu.

Philadelphia mural photography by José Antonio Gallego Vázquez/Unsplash.