How Endel’s AI-powered Focus soundscapes earned the backing of neuroscience

(Editor’s Note: This is the second in a series of articles Amazon Science is publishing related to the science behind products and services from companies in which Amazon has invested. The Amazon Alexa Fund first invested in Endel in 2018, and in 2020 the Alexa Fund participated in Endel’s $5 million Series A financing round.)

Founded in 2018, Endel creates personalized soundscapes to help people focus, relax, and sleep. Built on the back of its patented technology, Endel Pacific, the artificial intelligence (AI)-powered service takes into account the individual conditions of each listener, such as their heartbeat or the amount of light present, to generate customized sounds that help improve their well being, the company says.  

Endel provides three primary soundscapes: Focus, Relax, and Sleep. Using Alexa for instance, each soundscape is able to extract key local data about individuals, such as time of day, weather, and the amount of natural light, to help generate sound environments that improve these key states.

With the aim of helping people sleep better, Endel started collaborating with SleepScore Labs in 2020, to improve the effectiveness and user experience of their sleep soundscapes. The company also made headlines when it collaborated with musician Grimes to create “AI Lullaby”, a custom-made sleep soundscape which was made available through the Endel skill, for Alexa. 

Now, with the recent publication of a new white paper, "Differences In The Effects On Human Focus Of Music Playlists And Personalized Soundscapes, As Measured By Brain Signals", Focus mode is in the scientific spotlight. The white paper examines what properties of sound affect human focus, validating the company’s existing approach, while providing a roadmap for future improvements to its custom soundscapes. 

Focus results

Published by Arctop, a data and AI technology company that has developed a pioneering brain decoding SaaS solution, the white paper used Endel’s personalized Focus soundscapes, alongside focus-themed playlists from popular streaming platforms, to see how they affected a cross-section of users as they performed everyday tasks.

The white paper, which was authored by Arctop's research and development team led by principal investigator Dan Furman, PhD, and first author Aia Haruvi, MSc, was supported by Warner Music, Sony, Endel, and Universal Music, who provided the company with sounds, data, and financial support to help advance the research. The report looked at users at home in their natural environment, recording and interpreting their brain signals to show how they reacted to the music. The aim: examine what, if any, impact the use of Endel soundscapes, popular curated playlists that have been optimized for focus purposes, or just pure silence, had on the ability of listeners to perform tasks.  

“From the very beginning it has been important to us to be rooted in science,” says Endel co-founder and CEO Oleg Stavitsky. Upon launching Endel with renowned composer and sound designer Dmitry Evgrafov, Stavitsky began looking for research papers to inform their work within functional music, especially as it relates to helping people focus. 

“The majority of white papers out there would only reference popular music like Queen, Bach… making straightforward comments like, sad music makes you feel sad,” said Stavitsky.” There was nothing out there for what we were trying to apply here, anything that would help us go deeper and ask, ‘How does your brain react to certain types of sounds?’” 

When Stavitsky and Evgrafov received preliminary results from Arctop, it helped validate how their soundscapes impact brain activity on a second-by-second basis. 

Credit: Arctop

“This was gold for us,” Stavitsky says about the results. “It wasn’t just about validating what we had, it was about how it worked specifically. Arctop has this proprietary system that allows you to zoom into a song, and on a second-by-second basis say ‘here’s the progression and here’s the brain activity.’”

Arctop examined participants doing various tasks in their home or work environments. Listening to either Endel soundscapes, curated playlists, or just silence, each volunteer completed four, one-hour sessions, that included a set tasks, and followed by an activity of their own preference. As the participants performed their tasks, they were monitored using state-of-the-art technology to pick up on the brain’s impulses, tracking its responses to the audio in relation to their task. Through this analysis, the team devised a ‘focus coefficient’, based on input from a brain decoded data electroencephalograph headband, and additional survey data from the participants. 

The results demonstrated that participants listening to personalized soundscapes increased their focus significantly when compared to listening to music playlists, or silence.

“When we set up this experiment we didn’t know what would happen,” Furman explained. “One of our main takeaways is that the personalization of soundscapes is really effective.” 

The approach to the research is also relatively new, Furman explains. 

“One thing we want to highlight is that the method we used is naturalistic neuroscience – outside of the lab, with no technicians present, no wires... It was a uniquely natural capture of data. Here people were able to work at home, and use their own tablet or phone, they wore regular headphones and a light headband only for the brain decoding, which was really novel they were able to experience the content exactly as they would in everyday life. Ultimately, we believe that context, gives more credence to our findings.”

How focus works

Endel’s founders believe the study provides new information that the company can use to enhance its soundscapes. Unlike its other modes, Sleep and Relax, Focus is the only Endel soundscape to employ percussion. But it’s more complex than just adding a few beats.

“The tempo is closely tied to your heart rate, and can adjust based on your resting and active heart rate,” explains Evgrafov, who works closely with fellow Endel sound designer, Alexander Vasilenko, to bring its soundscapes to life. “The sounds are more active, have less reverb and are more nuanced. There is a very gentle balance that must be maintained with the rhythm, as the brain starts to block out rhythmic sounds after a time.” 

Credit: Arctop

Thanks to the way that in which the data was collected, Endel can now assess how sound impacts customers’ responses on a second-by-second basis.

“We got a lot of information about structure, where we realized we had to build it up, and relax things. In those transitions, the curve [for the focus coefficient] goes up drastically,” Evgrafov explains. “It’s not about the amount of instruments, it’s the nature of change that provides the most impact. This isn’t something we could have worked out ourselves.”

Further areas of focus 

From its inception, Endel has taken a scientific approach to programming its technology, applying information and knowledge on psychoacoustics that was readily available online, while at the same time relying on Evgrafov’s musicianship and heuristic knowledge.

“We started getting more neuroscience data, and that was more important for us, but we couldn’t answer simple questions like, ‘What is focus?’, and ‘What makes something relaxing?’ Now, thanks to the report, we see how the entire structure of a song impacts brain functionality,” Evgrafov said. “There are other layers of knowledge as well, such as the acoustical and other sound treatments that are present in the very spectrum of the sound. These parameters can help us program our core technology.”

Now, Endel is focused on taking its AI technology to the next level. 

“To me, what is important is how groundbreaking this is,” says Stavitsky. “This is more thorough and goes deeper than anything that has been done before, specifically about how sounds affect your cognitive state when it comes to concentration.”

Both Arctop and Endel see potential in further exploring additional factors that weren’t examined in the report, such as how personalized soundscapes can affect productivity, creativity, and wellbeing — states that can be directly associated with focusing. Using current Arctop technology for headphones, earbuds, AR/VR devices and the ‘focus coefficient,’ for example, Endel soundscapes can adapt in real-time to fit an individual user’s precise needs for focusing in the moment.   

“We believe personalized soundscapes are the new way to experience functional music,” Stavitsky says. “We see it as a new category of music — functional music — and within this field, Endel is a leader.”