What does it truly mean to experience fulfillment? How do you know if you're fulfilled or just getting by? If asked to rate your fulfillment on a scale from 1 to 10, where would you land? The challenge with self-assessment is that there's no universal standard—your 3 might feel like my 10. But what exactly makes something a 10 for you? Is it when you’re having a game night with friends or when your dog greets you with enthusiasm?

But if you don't know what truly resonates with you, how can you make choices that enhance your sense of emotional well-being?

At Immersion Neuroscience–the company who created SIX–we've solved this puzzle, tracing our insights back to the roots of psychology. William James, the pioneer of modern psychology, sought to map physiological responses to observable behaviors. He understood that introspection alone couldn’t reveal the motivations for our actions. In his groundbreaking 1884 article, "What Is an Emotion?," James differentiated between feelings (what we consciously report) and emotions (physiological responses that drive behavior). Often, these two are in conflict. 

I experienced this first hand while filming a segment for the BBC Show Animal Friends, where my mission was to measure oxytocin levels in different species who seemed to interact as ‘friends’, in order to see if there was biological evidence of true bonding.  As I drove to the shoot location, my heart began to race, and my breathing quickened. I assumed these were symptoms of excitement–which I found a little surprising since I’d appeared on television several times prior; however, I am an animal lover so thought perhaps that was the driver for my enthusiasm. As I continued to drive and felt my breathing become even more labored, I suddenly realized the real cause. The dry ice in my trunk which I’d brought to ship back the samples was venting carbon dioxide, starving me of oxygen. My body was fighting for survival while my mind misinterpreted the signals as excitement. 

This moment illustrates a profound truth: our conscious mind often misreads what's really happening inside our bodies. I consciously rationalized my racing heart and accelerated breathing as due to excitement, when my body was actually fighting for oxygen. Interestingly, Dr. Lisa Feldman Barrett shares a similar experience on the Hidden Brain podcast, where she misinterprets signs of the flu as attraction to a graduate school colleague. 

This disconnect between conscious perception and reality is why it can be so difficult to identify the things that truly make us thrive. When we self-report on the things we ‘like’ or ‘enjoy’, we’re only focused on what we think we feel, not the deeper neurochemical story unfolding beneath the surface.

At Immersion Neuroscience, we've harnessed this insight to create SIX–a revolutionary app that goes beyond surface-level perceptions to measure the subtle signals your body sends when oxytocin and dopamine flood your system. These are the critical moments that shape your memories, influence your decisions, and ultimately define your sense of fulfillment.

For nearly a decade, we’ve helped businesses and brands create better experiences and content for people like you, through a measurement we called Immersion, which represents a second-by-second neurologic measure of real-time emotional resonance. 

Driven by my lifelong mission to help people live longer, more fulfilling lives, I wanted to explore the connection between Immersion and fulfillment. Our research showed that tracking Immersion data could predict mood and energy levels with 98% accuracy. Peak Immersion experiences are strongly correlated with emotional well-being. But the question remained: how can we use this information to enhance our sense of radical fulfillment?

To answer this, I returned to the lab to determine how many peak Immersion experiences are needed to build emotional fitness. Our results revealed the answer: six. Experiencing six or more peak Immersion moments daily significantly improves emotional fitness. These moments, when we are truly thriving, are the key to living a radically fulfilled life.

That’s why we developed SIX, the world’s first app rooted in neuroscience that accurately measures your Key Moments—those peak Immersion experiences when you’re truly thriving. SIX integrates with your calendar to track which activities boost or diminish your emotional fitness, helping you curate your day for greater fulfillment.

Research from Oxford University shows that half of our happiness and fulfillment is linked to the quality of our social relationships. SIX quantifies these interactions, highlighting which friends, family, and activities most enhance your emotional fitness and which detract from it.

SIX also encourages you to build a supportive group of six friends—your “Inner Circle.” If a friend is struggling, SIX suggests sending a message of support, helping both of you to regain a positive state. While your SIX data remains private, you can share your progress with those closest to you. Supporting others often generates Key Moments for both the supporter and the supported, reinforcing the connection that builds emotional fitness.

No journaling or extra tasks required. SIX runs continuously, acting as your personal guide to emotional fitness. It has never been easier to identify the meaningful moments that make you personally thrive, so you can shape the life you want and optimize each day.

SIX is the free app you need to live a healthier, longer, and more radically fulfilled life. Download it today from the App or Play store. Six Key Moments, endless possibilities.