Earlier this month, we lifted the lid on the second volume of Sonic Science—our deep-dive biometric report into how digital audio impacts the human body, from subtle physiological effects to its ability to instantaneously boost our mood.

The research is packed full of insights for advertisers, as well as creative thought starters for making the most of a digital audio advertising campaign on Spotify.

But science is a dish best served by scientists themselves—so we sat down with Sonic Science advisor Josh McDermott, Ph.D, to hear the what, why, and how of this first-of-its-kind report.

1. Let's start with you, Josh. What's your professional background and how did you come to be involved with Sonic Science?

I study how people hear. My work is situated at the intersection of psychology, engineering and neuroscience—I conduct experiments on people to measure and understand our auditory abilities, and I build machine hearing systems that replicate aspects of these abilities and that we hope to harness to help people hear better. So I’m interested in pretty much everything related to sound, hearing, and music.

I was asked by Spotify in 2021 to serve as an advisor on their advertising research. The research intersects my interests in many places, speaking to the function of audio in our lives, what aspects of audio humans notice and remember, and how sounds make us feel. It has been a natural partnership, and a lot of fun.

2. Tell us about the thinking behind Sonic Science. What are the goals of the research and how is Volume 2 different from Volume 1?

The broad goal was to go out in the world and document the role of digital audio in everyday life. Most advertising research, including the research from Sonic Science Volume 1, takes place in a laboratory environment—which inevitably makes it hard to know whether what you measure is representative of what happens under more normal conditions. For Sonic Science Volume 2, however, we designed a study to measure responses to audio and audio advertising in as realistic conditions as possible.

We wanted to understand what people do when they consume digital audio, how it makes them feel, whether they choose what to listen to based on their activities and whether they remember ads that are delivered during these activities. We also aimed to measure physiological responses to audio as an online continuous measure of engagement.

3. Could you tell us a little more about the methodology used? How did we ensure the results were accurate and representative of a global consumer base?

We enrolled participants in both the US and UK who were active Spotify users. We asked them to wear a palm sensor each time they listened to Spotify, and to complete a brief survey before and after each listening session. Ads were delivered as they would be normally, with the exception that some of the ads were created in-house, featuring mock brands. That way we could ensure that someone recalling an ad was actually recalling something from the listening session, as opposed to something they might have heard elsewhere. People were otherwise unrestricted, and just did whatever they would normally do during their day.

So, it was a realistic and fairly comprehensive glimpse into the role of audio in modern human life. We might not have enrolled participants from other countries, but I’d bet that the main qualitative conclusions apply pretty broadly.

4. Give us the TL;DR on this year’s report. What was the focus, and what were the top trends for advertisers?

We found that people engage with digital audio across a wide range of activities—eating, commuting, studying, working, exercising, etc.—and that regardless of the activity, listening to Spotify improves the listener’s mood and increases physiological measures of arousal. We also found that people customise their listening experience, tending to listen to different types of content depending on what they are doing, yet still recall ads across all major activities documented in the study.

5. Which insights surprised you the most?

It was really cool to see the associations between the activities people engage in and the audio they consume. This is something that people have long suspected, but it has never been possible to test at scale in realistic conditions. The study we did was unique in measuring what hundreds of people listen to “in the wild”—essentially while they do whatever they do—over several weeks. For this reason, the dataset is unprecedented and reveals beautiful relationships between activities and audio attributes. For instance, people are much more likely to listen to music that’s instrumental (lacking vocals) and acoustic (lacking electronic effects) while studying. By contrast, high-energy activities—working out, walking, partying, etc.—are associated with music that’s more danceable and less acoustic.

The results provide evidence that people customise their auditory diet based on what they’re doing, suggesting that music and other digital audio plays an important functional role in our lives.

6. Sonic Science explores how digital audio affects our mood and behaviour, but it also goes beyond that. What else can advertisers expect from the report?

The research shows that digital audio ads work, even in realistic conditions when people are engaged in everyday activities—they remember the brands they’re exposed to during ads served via Spotify.

But the work also shows that streaming audio is different from traditional media in that people can and do customise their listening experience. I think the implication is that advertising could leverage this customized functionality, delivering content that fits what people are doing and listening to. To me, this seems like an underutilized opportunity.

7. And let's circle it back to you to finish: What music and podcasts do you listen to on a typical day, and when? Is there a particular context that you're more open to hearing ads in, based on how your favourite digital audio makes you feel?

I personally wish ads were more relevant to me, less disruptive to my listening experience, and more tailored to my taste. I love music—soul, disco, house, jazz—and I’ve curated a huge list of tracks I like on Spotify. I like to imagine a world where the ads I hear are integrated into my playlists, and my life. When I’m unwinding and listening to something relaxing, I’d like to think I’m more receptive to a lower-key ad with softer music that fits the vibe.

Part of what excites me about Sonic Science is that it highlights the potential to leverage streaming audio to make advertising a better part of the listening experience, while at the same time making ads more useful to the listener and thus more effective.