Disjunctive cognition is a common phenomenon in dreams, first identified by psychoanalyst Mark Blechner, in which two aspects of cognition do not match each other. The dreamer is aware of the disjunction, yet that does not prevent it from remaining. The most frequent disjunction is between appearance and identity, such as "I knew it was my mother, even though it didn't look like her." The dreamer recognizes a character's identity, even though the appearance does not match the identity. Such dreams are usually not experienced as bizarre, despite the fact that such a statement in waking life would be considered psychotic. In waking life, most people would assume that they misidentified the person and correct for it, but not in dreams. Disjunctive cognition can also involve time perception. It is quite common to dream that as an adult, one goes back to a time and place of one's childhood. In this case, the perceived age of the dreamer is disjunctive with the setting of the dream. It is much less common to perceive the opposite: dreaming of oneself as a child, where the time and place are that of one's adulthood. However, it is common to dream of other people whom one knew at an earlier age appearing in the present. This is especially frequent in the dreams of people who have lost close relatives. For example, Aharon Appelfeld reported: "I dreamed about my parents. They had not aged since we were together sixty-three years ago in Prague, and their faces expressed amazement that I had grown older. We were briefly united in mutual astonishment, and I knew that I had something important to tell them. But, as in every profound dream, I could not get the words out."
Blechner calls disjunctive cognitions "the commonplace bizarreness of dreamlife." Some things that happen in dreams feel bizarre to the dreamer, but disjunctive cognitions usually do not. Another commonplace bizarreness of dreams is the interobject, in which the dreamer sees something between two objects, as in: I dreamt of something "between a swimming pool and an aqueduct," or "between a cell-phone and a baby."
Disjunctive cognitions reveal much about how the brain is organized. Blechner has suggested that whenever disjunctive cognitions occur, the two aspects of cognition that are disjunctive are handled in different parts of the brain whose mutual integration is suppressed or shifted during sleep. Disjunctive cognitions between what the person looks like and who the person is suggest two brain systems for those aspects of perception. This is supported by research in neuropsychology and neurobiology. For example, some people who have suffered strokes or other brain damage have a syndrome known as prosopagnosia. A prosopagnosic man may look at his wife of 50 years, see all of her features clearly, and yet not recognize who she is. In such people, the process of seeing is intact, but the process of facial recognition is damaged. There is also the phenomenon of Capgras syndrome, in which a person may feel that a close relative is actually an impostor. The features of the relative are recognizable, but the person's identity is not. And there is also Fregoli delusion, in which a person may mistakenly identify strangers as people he actually knows. In all of these syndromes, there is a disjunction between the appearance and perceived identity of the person.
Neurobiological research has identified separate areas of the brain responsible for recognizing faces. In humans, identifying unfamiliar faces activates one region of the brain (the Fusiform face area) while recognizing familiar faces also activates another area of the brain (in the lateral midtemporal cortex). A similar division of function is found in macaque monkeys. Such findings indicate that the process of recognizing faces may be achieved by special parts of the brain that are different from the brain areas involved in analyzing the general visual features of things.
Since the brain has separate systems for deciding what a person looks like and who the person is, this division of labor may be responsible not only for disjunctive cognitions, but also the phenomenon of transference. In psychoanalytic treatment, patients frequently experience transference, in which the psychoanalyst is perceived to be very much like someone from the patient's past. As in disjunctive cognitions of dreams, the patient may feel "You look like Dr. X, but you feel like my mother." The separate areas of the brain involved in telling us what the person looks like and who the person is may give a neurobiological basis for transference, the phenomenon in which we know who a person is, yet we react emotionally to that person as if they are someone else.
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