A reader called me to say how much he enjoyed my book, The Other Brain, and then confided the true reason for his call: he wanted to share with me an extraordinary change in his brain and ask for my neurobiological insight. “After having a stroke I found that I could read other people’s minds,” he said.
I explained to the caller that I am a basic research scientist, not a medical doctor. (I was thinking psychiatrist to be specific.) “All of my ‘patients’ have fur and tails,” I joked. “I’m not able to offer medical advice.”
He was not deterred.
“After the stroke I could not speak for a long time, but strangely I could still sing. I’m a songwriter and musician–you would know my songs I’m sure.” He went on to describe how after suffering a stroke that left him mute, he could read the private thoughts and intentions on the faces of the hospital staff and people around him.
Quickly it became obvious to me that this person was not suffering a psychiatric illness nor was he describing a hallucination rooted in street-drug “pharmacology.” The man was completely lucid, articulate, and very intelligent. What he was experiencing, I concluded, had developed from a neurological disorder.
As he laid out his life history, I was reminded of how many people who lose a sensory ability sometimes develop heightened abilities in other senses. The blind can develop extraordinary abilities to hear, for example. Some blind people can perceive speech sped up to three times the rate at which a sighted person can comprehend, understanding with ease what sounds to everyone else like babble. Others can echolocate to navigate the world without vision. Ray Charles and Stevie Wonder are famous examples of people in which extraordinary musical ability was unlocked or developed with the loss of vision and increased reliance on hearing.
As far as mind-reading goes, I appreciative how much of what the brain does operates deeply below the level of consciousness. I know that humans utilize a rich vocabulary of body language that works almost entirely subliminally. The world bombards us with a blizzard of signals. Our brain takes them all in, evaluates them, synthesizes them, makes decisions and influences our conscious mind through subtle feelings and urges. Only a sliver of this perception and analysis reaches the level of consciousness. As a mountain climber I have learned to listen carefully to these subconscious perceptions or subtle feelings, and to respect them in myself and in my climbing partners. Our fates on the mountain are tied together by the rope knotted about our waists. If it just doesn’t “feel right,” that’s enough said–something’s not right. We back off the mountain to return another time or by a different approach.
So I speculated that the losses associated with the stroke had forced the caller’s brain to rely more heavily on other channels of perception that were previously suppressed by the predominance of the conscious mind, and perhaps he had developed them to a greater extent than before. He had probably developed a heightened sensitivity to body language. This seemed to make sense to both of us.
As we closed the conversation I asked, “You mentioned that you were a musician and that I might know some of your songs.” He revealed the name of the hit he wrote which had made him and his rock band legend. The song is one of my favorite rock tunes–a finger plucking guitar classic that I enjoy playing on my Martin D15. The lyrics are timeless. A delusion of grandeur I wondered? He might claim to be Jesus Christ and thoroughly believe it, I reminded myself. But as we discussed the musical intricacies of the piece it was obvious that he indeed knew the score intimately. His revelation was no fabrication, as I later confirmed. He confided his story to me in confidence, so I don’t have the right to reveal his identity, but you would surely know the artist’s band and his classic rock song. The world is indeed a small place.
I was reminded of this phone call when I read a new study from the University of Bologna, Italy, by psychologists Bertini, Cerere and Lavadas writing in the journal Cortex. The researchers studied people who were blind in one eye, and their experiments revealed that the sightless eye was able to communicate to the brain unconsciously. This is not ESP pseudoscience; this is hard-core neurophysiology. Remember what I told the rock musician? The brain is able to take in much more information subconsciously than we can possibly hold in our conscious mind. Neuroscientists are beginning to map out the hidden brain circuits that are responsible.
To make this discovery the researchers flashed pictures of faces on a computer screen and asked the subjects to identify whether the faces were male or female and whether their facial expressions were happy or fearful. What the subjects did not know, because they could not see through their blind eye, was that the researchers were also flashing pictures simultaneously to the sightless eye. The surprising result was that when they flashed a picture of a person with a fearful expression to the sightless eye simultaneously with an image shown to the good eye, the subjects were able to identify the gender and facial expression of the picture shown to their good eye much faster.
But here’s the most important clue: this sped up reaction time only occurred when the researchers showed the blind eye a picture of a fearful face while showing a happy face to the sighted eye. Fear or alarm on the faces of others, even though it was impossible to see visually through a blind eye, alerted their mind to danger and elevated their mental performance to a heightened state of vigilance.
You see, these people were blind in one eye as a result of a brain stroke or traumatic brain injury to the part of the brain that gives us the sense of vision–the visual cortex located at the back of the skull. The eye itself was not damaged, and recent research has shown that there is a pathway from the eyes to the part of the brain responsible for vigilance, detecting threat, and fear, called the amygdala. This subconscious pathway deep below the cerebral cortex remained intact. Although the subjects cannot see through their blind eye; that is, they have no vision through it, the unconscious pathway to the brain center responsible for detecting threats remained intact. Fear on the face of someone else means that there is good reason for you to fear or become alert to danger as well. In many threatening situations, sending signals to the visual cortex and consciously evaluating the danger would take much too long. So Nature has given us a high-speed pathway for alarming visual information to reach the part of the brain that is always on guard for deadly threats. In many life-or-death situations, the regal conscious mind is just too slow and stupid.
Bertini, C., Cecere, R., Ladavas (in press) I am blind, but I “see” fear. Cortex, on line in advance of press. doi:10.1016/j.cortex.2012.02.006
My Scientific American report on blind people’s ability to comprehend greatly accelerated speech: //www.scientificamerican.com/article.cfm?id=why-can-some-blind-people-process