David J. Linden, Ph.D., is a Professor in the Department of Neuroscience at the Johns Hopkins University School of Medicine. His laboratory has worked for many years on the cellular substrates of memory storage in the brain.
He applied the "Page 99 Test" to The Accidental Mind, his book that "seeks to explain how brain evolution has given rise to those qualities that most profoundly shape our human experience," and reported the following:
Hmmm-- I wonder if Ford had non-fiction in mind when he proposed the “page 99 test.”Visit The Accidental Mind website and read some free chapters from the book.
Flipetty, flip. flip. Ah, here’s the stuff…
What I hope to show here is that perception and emotion are often inextricably linked. There is little, if any, “pure perception” in the brain. By the time we are aware of sensations, emotions are already engaged. Fascinating examples of this can be seen in two complementary types of brain damage. In 1923, the French physician Jean Marie Joseph Capgras described a patient who, following temporal lobe damage, could still visually identify objects and human faces, but these objects and faces did not evoke any emotional feelings. As a consequence, this patient, suffering from what is now called Capgras syndrome, became convinced that his parents had been replaced by exact human replicas.
One explanation is that he was led to this conclusion because the emotional responses he expected to feel when seeing his parents weren’t there and, consequently, the only reasonable explanation was that these people looked like his parents but were not actually they. The problem was exclusive to vision: the voices of his parents still sounded genuine.
Since the original description, quite a few more cases of Capgras syndrome have come to light and some of these have been observed quite carefully. Capgras syndrome is most often manifest as a feeling of parental imposters, but it can occur for anyone or anything for which there is an expected strong emotional response — pets, for example. Many Capgras patients find mirrors extremely disturbing: they recognize that the reflected image resembles themselves, but they are also convinced that the reflection is of an imposter. Often, this is terrifying because the reflected image is thought of as a malevolent stalker, determined to ruin the life of the patient.
Capgras patients do not have a simple problem with either visual discrimination or emotional responses. In the laboratory, they can easily make distinctions between similar faces and objects. They do not hallucinate and can have appropriate emotional responses to auditory stimuli. These observations, together with anatomical evidence, support the view that Capgras syndrome is specifically a defect in information transfer between the later parts of the visual “what” pathway and the emotion centers, including the amygdala.
I then go on to talk about the another case in which people who are blind from damage to the visual cortex of the brain can still detect emotional content of faces through the use of a second, ancient visual system in another brain region that remains intact.
Overall, I feel like I’ve caught a break — page 99 does give a rather good flavor of my book and it touches, albeit obliquely, on the book’s main argument — that our human experience is profoundly impacted by the quirky and inefficient way in which our brains have evolved.
--Marshal Zeringue