Dr. Tanya Marie Luhrman, a psychological anthropologist at Stanford University, retells an old joke: When you talk to God, we call it prayer, but when God talks to you, we call it schizophrenia.

But in her special report for CNN, Dr. Luhrmann offers a surprisingly supportive scientific analysis of evangelical Christians who claim that they have heard God speak to them. She concludes by stating, "Science cannot tell us whether God generated the voice that Abraham or Augustine heard. But it can tell us that many of these events are normal, part of the fabric of human perception." There you have it: If you hear God speak to you, you might not be crazy after all.

Dr. Luhrmann concludes with a powerful example of hearing Jesus speak: "When the Rev. Martin Luther King Jr. sat at his kitchen table, in the winter of 1956, terrified by the fear of what might happen to him and his family during the Montgomery bus boycott, he said he heard the voice of Jesus promising, 'I will be with you.' He went forward."