Different auditory stimuli can modulate the emotional and physiological responses associated with an anxiety disorder, explained Norberto Naal, a research professor at Tecnológico de Monterrey’s School of Humanities and Education (EHE).

Naal and a multidisciplinary team investigated how 3D soundscapes—acoustic environments made up of a collection of sounds that characterize a particular setting—could serve as a tool to support mental health.

After observing a range of emotional responses in their studies, the researchers developed four soundscapes to test: an urban park, a market, an electronic music concert, and a war zone.

“In recent years, many more efforts have been made to present these soundscapes in more immersive formats with the aim of supporting people’s health, but the work is still highly exploratory,” Naal said. “It is a new and timely subject, and there is still a great deal to investigate.”

Approximately 359 million people were living with an anxiety disorder in 2021, according to the World Health Organization (WHO). In Mexico, 21.4% of the adult population showed signs of anxiety in 2025, yet only one in four people receives care.

Naal, who also coordinates research projects for the Laboratory for Advanced Analytics and Decision Sciences and the Behavioral Research and Public Opinion Lab at Expedition FEMSA, noted that the project has involved specialists in neuropsychology, otolaryngology, biomedical engineering, and audio engineering and music production.

Sounds and Emotions: The Study That Preceded the Soundscapes

During his master’s and doctoral studies, Naal pursued a line of research in acoustics for health under the guidance of David Ibarra and Luz María Alonso, scientists at Tec’s School of Engineering and Sciences (EIC).

They focused on understanding how sounds affect people and characterizing how the Mexican population responded emotionally to different auditory stimuli.

More than 150 sounds were evaluated with the participation of over 300 people from several regions of the country, including at least one participant from every state.

In this study, which was conducted remotely during the pandemic, participants listened to the sounds and rated three dimensions: valence, or how pleasant or unpleasant the sound was; arousal, or how stimulating it was; and dominance, or how much control they felt they had over their emotions.

The results helped identify which sounds produced pleasant and calming sensations, which were neutral, and which created a sense of threat. Based on that characterization, the researchers turned their attention to designing the soundscapes.

To design them, the team combined field recordings with some audio sourced from libraries. They then used specialized software to position the sounds virtually around the listener, creating an immersive three-dimensional experience in which the sounds could be perceived from different directions and even move around the person.

“In every community, in every part of the world, this series of sound events can shape our customs and the way we feel emotionally, and can even elicit either a positive or negative response,” Naal explained.

Although one might assume that most of these soundscapes were intended to induce relaxation, Naal said that the war-zone soundscape was designed to explore what happened when people heard loud or disturbing sounds and whether those sounds, too, could help reduce anxiety.

“It sounds contradictory, doesn’t it? But if we think about it, some people play war-themed video games to unwind for a while or take their mind off something that is worrying them,” he said.

An Immersive Experience to Measure the Effects of Sound

To learn how these soundscapes could influence anxiety, the researchers conducted an experiment involving 60 participants. First, they induced a temporary anxiety response under controlled conditions to observe how people reacted before and after listening to the different environments.

For about five minutes, participants viewed a series of unpleasant images, including animals, blood, and violent scenes. The images were selected from the International Affective Picture System, a database used in research to elicit and study different emotional responses.

After this exposure, each person put on headphones and listened to one of the four soundscapes in 3D audio. A control group instead followed an audio guide developed by the WHO during the pandemic, featuring exercises designed to help regulate emotions in stressful or anxiety-inducing situations.

In addition to asking participants how they felt, the team measured their cardiac activity and skin perspiration.

“The heart’s response and perspiration are closely tied to responses from the autonomic nervous system, which is activated in threatening or highly arousing situations. They are almost direct indicators of transient emotional changes,” Naal said.

The protocol was approved by Tec’s Clinical Research Committee, and the Emotional Counseling Department was available to provide psychological support if any participant needed it.

Different Responses to Soundscapes

The study’s results showed that the soundscapes associated with pleasant emotions had clearer effects. For example, the park helped participants recover emotionally: it lowered anxiety levels and created feelings of relaxation and well-being.

“The electronic music concert also reduced anxiety levels, but it maintained emotional arousal”—in other words, it was stimulating—Naal explained.

The market also produced a gradual decrease in anxiety, though to a lesser degree than the park and the concert. The war zone, on the other hand, caused higher anxiety levels—even higher than those triggered by the images—and also produced unpleasant feelings and high emotional arousal.

“We could say that 3D audio amplified the expected response to the stimuli,” he said. “If a stimulus was already going to feel pleasant, presenting it in 3D may make it feel a little more pleasant or slightly more arousing and stimulating.”

As for the physiological measurements, the team found differences in heart rate depending on the soundscape and whether it had been designed to produce higher or lower emotional arousal.

Heart rate decreased during the park soundscape, for example, but increased during the concert. Skin perspiration, meanwhile, showed no significant differences among the soundscapes, which, according to Naal, suggests that other types of measurements need to be incorporated.

The Project’s Next Steps

The team is now seeking to incorporate technologies such as electroencephalography to gather more information about the brain’s response to these stimuli, combine 3D audio with visual experiences in virtual and extended reality, and study its effects on other emotional states, such as stress.

Naal said that this line of research still needs to advance before these experiments can be turned into solutions. He added that continuing to study the interaction between the senses and the body’s responses could pave the way for the development of new tools to address problems such as anxiety.

“The idea is to continue conducting research so that, in the future, we can develop these alternatives that could benefit people’s mental health,” he said.

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