I have been developing The Four Factors for many years. To be clear, I’ve never hooked up electrodes to lab rats and played Barry White music to see how they respond; though I’ve always wanted to see a rat slow-dance. But I have done significant research for this book. I've interviewed hundreds of women and men about their relationships and have spent significant time listening to their relationship stories as well as hearing their perspectives on The Four Factors. I’ve also studied thousands of online dating profiles looking for what really matters in romantic relationships. Finally, I've read about every relationship book I could get my hands on including Why Him? Why Her? by Helen Fisher, The Five Love Languages by Gary Chapman, and even the funny He's Just Not That Into you by Greg Behrendt. I've studied how their themes fit together and how they fit within The Four Factors.