The emotional-transference hypothesis could certainly explain the case of Winifred Potenza, a slender, middle-aged artist with mournful brown eyes who lives in a wood-shingled home on a quiet street in Santa Rosa. In September, 1989, just a few blocks from her house, a drunken William Ernst doing 70 mph plowed into the car carrying her 21-year-old son Jonathan, and his fiancee, Lisa Rodriguez. Both were killed instantly. Ernst, a young man almost Jonathan's age, had already been convicted once of driving under the influence.

"I went nuts. I wanted him to suffer," Potenza says. "I would have killed my neighbor if I thought it would bring back my kid." Potenza spent months lobbying the district attorney to prosecute Ernst for murder, not the manslaughter charge such killings usually receive. She got her wish: Ernst was convicted of murder and sentenced to 15 years to life.

But just as the judge pronounced the sentence, Potenza says, she had a stunning emotional insight. There in the courtroom, with Ernst's weeping mother just a few yards away, she saw him as a person for the first time, and realized the whole thing was a tragic accident. "It was like waking up," she says. "I thought, 'Of course I forgive him.' " She found herself getting up, embracing Ernst and telling him so. "It felt beautiful. I forgave him completely. I've never held it against him since."

Then, she says, she had to make amends. For the next six years, Potenza became Ernst's staunchest advocate, visiting him weekly in prison and lobbying all the officials she could find to release him. He was finally paroled. He and Potenza remain close friends.