Why do some people quickly link up with mates who love them good and strong, while others gravitate to people who hurt them, dump them or withhold love? It's all in the neurochemistry. I've come up with a metaphor that helps explain this painful syndrome. When you're a little kid, you get used to your mom's spaghetti sauce; it's the one that tastes right, the one against which all other spaghetti sauces will be judged. (Please substitute latkes, baba ganoush, banh xeo or whatever; and for mom, use dad, another primary caregiver, or Boston Market.) When you leave home and get more experience, your tastes may broaden. But when you're a kid, it's the ONLY real spaghetti sauce. Your parents take you out to a dinner at a fancy Italian bistro, and that spaghetti just sucks. You sleep over at a friend's, whose dad simmers organic heritage tomatoes with oregano fresh from the garden? Ick! Well, every family lives in a neurochemical stew that's just as redolent as that sauce. It's made up of cortisol, for stress; oxytocin, for intimacy; adrenaline, for fear; serotonin, for calm -- and probably a few other things we haven't yet figured out. And the taste of the family chemistry feels normal. It maybe doesn't feel good, but it feels normal. It's a different kind of home cooking: the neurochemical kind. So, if you grew up simmering in cortisol and adrenaline, and you meet someone whose chemistry is oxytocin-rich, it feels bland. Wimpy. Boring or smothering. Without that seasoning of stress, the blend isn't right. To take the metaphor further, say your mom salted her sauce with a wild hand. What if she had Munchausen by Proxy syndrome and actually added a dollop of poison to her sauce? This still will be your ideal of home cooking. In the same way, you'll keep searching for someone who can help you recreate the poisonous atmosphere of your family. For people raised by abusive or neglectful parents -- and maybe, to a lesser extent, for all of us -- this goes much deeper than a feeling of comfort or social recognition. The family in which you spend your first three years or so of life actually determines how your brain will develop. Michael De Bellis, a psychiatrist on the faculty of Duke University School of Medicine's Pediatrics Department, studies the brains and cognitive functioning of traumatized kids using fMRI. He's found that early childhood experience has a powerful influence on how the brain develops -- and he's found that compromised brain development leads to permanent impairment. At the Stanford School of Medicine, Victor Carrion has done several brain imaging studies that show that stress, trauma and abuse alter the brain. If you were lucky enough to escape childhood trauma, nevertheless, your experience in your family has subtly shaped your own brain development. So, when two people meet, they may not be using exactly the same equipment to interact. The saying, "We're not on the same wavelength," could be literally true. If Mom made great spaghetti, there's no harm in seeking a mate whose home cooking smells the same. But, just like with food, sometimes it's better to find a healthier alternative.