How old do you feel at this very moment? I’m not talking about your actual age, or the age you feel after a workout when you’re not quite as limber as you used to be. (We all have those moments.) What I mean is, what age do you actually feel like, deep down?

We all have multiple ages. The first is our actual physical, chronological age. Then there’s our inner age, the age we feel emotionally. I call this “emotional age” our Twin Self. And if you’re working on building a successful brand, considering your audience’s Twin Self is a huge part of reaching them – figuring this out may have saved iRobot the manufacturers of the Roomba vacuum cleaner.

For most people, the age of their Twin Self falls between 18 and 26 years old. This is when many of us are leaving home for the first time, heading to college, moving into first apartments, buying a car, taking some risks as we discover ourselves. It’s often when we start to make major choices on our own.

Of course, there is no set age for a Twin Self — a 47-year old man told me his inner age was 40, since that was when he married his wife and they moved into their dream home. It was the first time he had felt truly liberated. I started my first advertising agency when I was 12 years old, and I believe that 12-year old me is very much an influence on my worldviews today.

The Twin Self has been useful for me in many of my projects, but it really springs to mind from my work with iRobot. After soaring to over 10 million units sold, sales inexplicably plateaued. They brought me in to figure out why people just weren’t that into buying a Roomba anymore, and how they could regain their popularity.

I embarked on some Subtext Research — that is, going directly to the homes of Roomba owners and interviewing them there to see what clues I could find, both in their words and their surroundings.

The first thing I found was that Roomba owners are tremendous lifelong brand ambassadors. They are quick to tout the wonders of the Roomba to everyone they meet. Second, they regard their Roombas almost as a member of the family. Some even name them: Whitie, Big Red, Spot. Over and over, I heard the word ‘cute’ to describe the Roomba as it zoomed across the floor, bouncing off of the walls and chairs.

I also noticed they all had objects on display that they admitted to rarely using, but which conveyed a certain kind of persona. One woman had a pattern hanging off a sewing machine that she admitted she hadn’t used in 15 years. One man had a hydroponic plant garden that yielded only three or four tomatoes a year. Another, a basket of toys for his nephew who only visited once or twice a year.

Of the Roomba owners I interviewed, almost all of them worked highly structured, disciplined, administrative jobs with establishment titles. They were lawyers, insurance claim adjusters, middle managers. But at home, they put on different personas through small, rebellious quirks and displays of personality. A sewing machine. A hydroponic garden. A basket of toys. I call these personal touches “Breaking the Frame.” It’s the alternate life that they are forbidden to express in their tightly structured day jobs.

And every one of them had a Roomba. Not only that, but in almost every home the Roomba was also partially on display, just like the other objects that were Breaking the Frame.

I mulled over the concept of the Twin Self and the ways in which Roomba owners Break the Frame, but I still wasn’t quite hitting on why people were no longer buying Roombas. It wasn’t until I was working on my next job with Pepsi that I had a breakthrough on Roomba’s problem. My work on Pepsi had led me to realize that sound influences how we taste things, and to refresh their brand Pepsi needed to “own” their sound. The crack of a can opening, the glug-glug-glug of pouring one out, the soda fizzing in the glass.

So what does sound have to do with a Roomba? Well, the original Roombas took some cues from R2-D2 and made robot sounds. They said “uh-oh” when they bumped into a wall, and made a ‘dood dood’ sound when backing up. Roomba owners I spoke to loved these cutesy sounds. It was adorable, and it was removed from later models so that the Roomba was now a silent disc performing its task. No personality whatsoever. Its humanity was gone.

Sure, the Roomba performs its task as a vacuum and that’s all well and good, but the talking Roomba hit on a feeling of childlike wonder. It’s a toy, a pet, a baby, a conversation piece, and a displacement for the owner’s identity. In short, the chatty Roomba spoke to the Twin Self within them, and it also gave them another way to Break the Frame and be a little quirky at home.

So the answer for Roomba was simple: bring back the sound! And now, with Amazon Alexa and Google Assistant, owners can even talk back.

As you build or refresh your brand, try to think about the Twin Self. These dualities speak volumes about what people really want out of the world. It may take a lot of digging, but when you can reach your customers on this deeper, more personal level and keep them for the long-haul, it’s worth it.

Martin Lindstrom, one of the world’s foremost branding experts, and author of Small Data: The Tiny Clues That Uncover Huge Trends. His previous books have been translated into 47 languages and have sold well over one million copies. He was named one of TIME magazine’s 100 most influential people in the world. In 2016, Thinkers50 named him one of the top 20 business thinkers in the world, and he has been ranked the world’s #1 branding expert for three consecutive years. His articles appear in The New York Times, Harvard Business Review, and Fast Company. He advises startups and a Who’s Who of Fortune 100 companies on branding, communication, consumer psychology, retail, innovation, and transformation. Lindstrom currently hosts Main Street Makeover, a series on NBC’s TODAY show that creates solutions to business problems in less than just 24 hours.