The Tell-Tale Brain: A Neuroscientist's Quest for What Makes Us Human

Now you may well wonder why we should go through the elaborate process of measuring GSR to monitor emotional arousal. Why not simply ask people how something made them feel? The answer is that between the stage of emotional reaction and the verbal report, there are many complex layers of processing, so what you often get is an intellectualized or censored story. For instance, if a subject is a closet homosexual, he may in fact deny his arousal when he sees a Chippendales dancer. But his GSR can’t lie because he has no control over it. (GSR is one of the physiological signals that is used in polygraph, or so-called lie-detector tests.) It’s a foolproof test to see if emotions are genuine as opposed to verbally faked. And believe it or not, all normal people get huge GSR jolts when they are shown a picture of their mothers—they don’t even have to be Jewish!

Based on this reasoning we measured David’s GSR. When we flashed neutral pictures of things like a table and chairs, there was no GSR. Nor did his GSR change when he was shown unfamiliar faces, since there was no jolt of familiarity. So far, nothing unusual. But when we showed him his mother’s picture, there was no GSR either. This never occurs in normal people. This observation provides striking confirmation of our theory.

But if this is true, why doesn’t David call, say, his mailman an imposter, assuming he used to know his mailman prior to the accident? After all, the disconnection between vision and emotion should apply equally to the mailman—not just his mother. Shouldn’t this lead to the same symptom? The answer is that his brain doesn’t expect an emotional jolt when he sees the mailman. Your mother is your life; your mail carrier is just some person.

Another paradox was that David did not have the imposter delusion when his mother spoke to him on the phone from the adjacent room.

“Oh Mom, it’s so good to hear from you. How are you?” he would say.

How does my theory account for this? How can someone be delusional about his mother when she shows up in person but not when she phones him? There is in fact an elegantly simple explanation. It turns out that there is a separate anatomical pathway from the hearing centers of the brain (the auditory cortex) to your amygdala. This pathway was not destroyed in David, so his mother’s voice evoked the strong positive emotions he expected to feel. This time there was no need for delusion.

Soon after our findings on David were published in the journal Proceedings of the Royal Society of London, I received a letter from a patient named Mr. Turner, who lived in Georgia. He claimed to have developed Capgras syndrome after a head injury. He liked my theory, he said, because he now understood he wasn’t crazy or losing his mind; there was a perfectly logical explanation for his strange symptoms, which he would now try to overcome if he could. But he then went on to add that what troubled him most was not the imposter illusion, but the fact that he no longer enjoyed visual scenes—such as beautiful landscapes and flower gardens—which had been immensely pleasing prior to the accident. Nor did he enjoy great works of art like he used to. His knowledge that this was caused by the disconnection in his brain did not restore the appeal of flowers or art. This made me wonder whether these connections might play a role in all of us when we enjoy art. Can we study these connections to explore the neural basis of our aesthetic response to beauty? I’ll return to this question when we discuss the neurology of art in Chapters 7 and 8.

One last twist to this strange tale. It was late at night and I was in bed, when the phone rang. I woke up and looked at the clock: it was 4 A.M. It was an attorney. He was calling me from London and had apparently overlooked the time difference.

“Is this Dr. Ramachandran?”

“Yes it is,” I mumbled, still half-asleep.

“I am Mr. Watson. We have a case we would like your opinion on. Perhaps you could fly over and examine the patient?”

“What’s this all about?” I said, trying not to sound irritated.

“My client, Mr. Dobbs, was in a car accident,” he said. “He was unconscious for several days. When he came out of it he was quite normal except for a slight difficulty finding the right word when he talks.”

“Well, I’m happy to hear that,” I said. “Some slight word-finding difficulty is extremely common after brain injury—no matter where the injury is.” There was a pause. So I asked, “What can I do for you?”