This post is by Gail Marie, brand journalist at McKinney.

Call them stories, narratives or yarns, science has proven that they can "change our attitudes, beliefs, and behaviors." So says Paul J. Zak in the Harvard Business Review and many chief creative officers every day. Specifically, by measuring oxytocin levels, Zak found that our brains are most attracted to visual stories of characters who try to overcome adversity, and that our attention is most concentrated when the outcome is uncertain.

The world's most successful podcast, Serial, proved the same effect is possible with stories we can only hear, so much so that the phrase "the Serial Effect" was coined and the entire podcast platform benefited. A McKinney survey of Serial's newsletter subscribers showed 23% had never listened to a podcast before Serial, and nearly half of them are now listening to other podcasts at least once a week.

McKinney's Chief Creative Officer Jonathan Cude met with the creators of Serial on stage at the Cannes Lions Festival of Creativity last month to talk about how these storytelling heroes did it and what marketers can learn from them. This is what I took from their conversation.

Start with what you know

All writers are told to do this, and the creators of Serial did it, too. Host Sarah Koenig, Executive Producer Julie Snyder and Producer Dana Chivvis are award-winning journalists (all three just won Peabody Awards). All three spent a collective 35 years working on This American Life, one of the first successful podcasts and another Peabody Award winner. It only made sense for them to start a podcast that relied solely on investigative journalism.

And it worked. But what the Serial creators didn't immediately realize they were also doing – and an undeniable part of the podcast's draw – was making the podcast about their experience of investigating. They were good at that, too, but it had never been done before.

At Cannes, Snyder explained that the only way to deal with their uncertainty about the reported facts of the case, about the trial, about Adnan, was to admit it. This level of personal and professional vulnerability in journalism is unheard of. Snyder told the Cannes crowd that male reporters may not have taken that risk. Digiday Editor Shareen Pathak tweeted during the panel, "Male reporters are less likely to show uncertainty about their stories. Women are more comfortable with ambiguity."

Both agencies and their clients could learn from Serial's risk taking. As Cude said, agencies, too, go where the story of a brand takes them, and sometimes it takes a brave client to follow them there. It may also require an uncomfortable level of vulnerability.

Make it personal

After the first episode, the theme music alone conjured what all Serial listeners imagined Woodlawn High School to look like in 1999. We knew Sarah's voice, how prepaid calls from a Maryland correctional facility begin, and attorney Cristina Gutierrez's "extremely polarizing speech mannerisms" (aptly described by Bustle writer Arielle Dachille). Most of us heard them through devices literally stuck in our ears, making the listening experience exceptionally personal.

Every time we listened, it was just us and Serial. And we listened carefully: Almost all Serial newsletter subscribers (93%) reported giving their full attention to every 60-minute episode.

Keep in mind that the oxytocin test done by Zak measured a brain's response to visual stories. Perhaps the extra engagement of Serial listeners' imaginations to invent the images made this story even more personal. After all, we could only assume that what we saw as we listened – the Best Buy parking lot, the courtroom, the pay phone – was exactly what Koenig, Snyder and Chivvis saw, too.

That said, brands hoping for committed and engaged audiences don't have to crank out the next best podcast. The podcast part is irrelevant. The Cannes Grand Prix-winning #VolvoContest didn't happen through our ear buds. We didn't imagine the dog eating spaghetti in Geico's preroll.

Tug at heartstrings

If generating empathy could be measured on the Billboard Top 10, Serial would be anything by Taylor Swift. How'd they do that? With tension. Listeners were conflicted by the story being reported and by the story of the reporters themselves. Because the podcast was serialized and because the investigation was following real-time leads, we felt like we were going on the same ride as Sarah, Julie and Dana. And we cared.

Zak's tests proved that once we care, we're hooked. Serial drew out tension one hour a week for 12 weeks, giving listeners nothing between episodes. But Serial didn't have to: There were podcasts about Serial, recaps published in online magazines and a Serial Reddit page for 24-7 discussions. McKinney's survey results show that 99% of listeners listened to all episodes, and some listened more than once. Many of us manufactured long-term relationships with Serial's real-life characters, including the podcast's creators.

If this sounds like an impossible situation for marketers to model, buck up. With a narrative arc and enough adversity to cause tension and warrant resolution, it's possible to do it in mere seconds. Remember the buckets of ice water we poured over our heads for ALS? All 2.4 million #IceBucketChallenge videos had what Serial has:

  1. A character who must perform a difficult task.
  2. A temporary (and often humorous) resolution when he does.
  3. More tension as we wait to see if those he challenged will do it, too.

The podcast format alone didn't make the story behind Serial a standout success. It was how the story was told. It always has been.