Once, there was a young man who got into a horrific car accident. From then on he could still recognize faces, but wouldn't acknowledge them to be the loved ones that he knew. It wasn't amnesia. He would go to his mother's house and he'd say, "You look like my mother, you sound like my mother, you even smell like my mother. But I know you're not my mother. You are an impostor." He imagined that the world had created an elaborate conspiracy of clones to fool him. Because you see, your brain gives you a biological signal when you connect with someone. And without that signal, you can't recognize anyone -- even if all of the other signs tell you that the woman standing in front of you is your own mom.

At home I felt precisely like this. The valley had been filled with crowds of strangers, and often my throat clenched when I realized I had known these people my entire life. I just couldn't put two and two together.