Monothematic Delusions and the Perception of Identity
by Sarah Perry [theviewfromhell.blogspot.com]
The monothematic delusions are the scariest delusions because they are the kind of delusion that often afflicts otherwise sane, rational people - that is, people with whom it is easy to identify. The presence of a delusion in a mind like ours forces us to imagine our own minds coping with a delusion. But the content of the monothematic delusions is also profoundly creepy on a deep and probably foundational level. It is creepy that these particular delusions, these particular false beliefs that are not changed by any amount of evidence, occur in just these patterns all around the world.
For example, there is the Capgras delusion, in which the deluded person believes that his close relatives (but not acquaintances) have been replaced with identical-looking duplicate copies,Invasion of the Body Snatchers-style. The most famous example is the patient known as "DS," described in a 1997 paper by V. S. Ramachandran (Hirstein, 1997); DS developed the Capgras delusion after injuring his head in a traffic accident. His delusion was creepily specific: he believed his parents had been replaced by doppelgangers when he observed them visually, but he did not have this belief when he spoke to them on the phone.
The creepiness seems to have a tidy neuroscience solution: DS (and by extension Capgras patients) can recognize faces, but cannot connect the visual recognition with the appropriate emotional response. Auditory recognition and its appropriate emotional response are not so affected. DS sees his mother's face, but doesn't feel the familiar emotions he should feel when looking at his mother; therefore, his senses scream at him that this person is not his mother. The doppelganger story is the only thing that makes sense, given this direct perception.#
Most likely, the Capgras delusion is an organic, physical brain situation, like color blindness. Color blindness is not generally held to be a delusion, as it is a disorder of perception, rather than of reason or belief. The apparatus that the self uses to sense the world is broken, one might suppose, but the self inside is unaffected.
But just as a colorblind person may admit that others seem to see colors he does not, the person with a monothematic delusion may admit that his beliefs are bizarre and not held by the rest of the population. Nonetheless, the bizarre perception remains and informs all his other processes, including his internal narrative.
Another monothematic delusion occurs when the afflicted person believes one of his limbs doesn't belong to him - and often wishes to have it amputated. When this bizarre belief was seen as a sexual perversion, perhaps contagious and definitely transmitted via the internet, it was called apotemnophilia (Elliot, 2000). But once it became clear that this, too, was a specific brain wiring issue and not a more general "failure of reason" - when it became clear that affected patients' brains failed to "map" the limb in question onto their internal self-representations (Vallar, 2009) - then the delusion came to be called by the less prurient name somatoparaphrenia.
Here are the rest of the monothematic delusions, from Wikipedia ("Monothematic delusions," 2011):
Fregoli delusion: the belief that various people who the believer meets are actually the same person in disguise.
Intermetamorphosis: the belief that people in one's environment swap identities with each other whilst maintaining the same appearance.
Subjective doubles: a person believes there is a doppelgänger or double of him or herself carrying out independent actions.
Cotard delusion: the belief that oneself is dead or does not exist; sometimes coupled with the belief that one is putrifying or missing internal organs.
Mirrored self-misidentification: the belief that one's reflection in a mirror is some other person.
Reduplicative paramnesia: the belief that a familiar person, place, object or body part has been duplicated. For example, a person may believe that they are in fact not in the hospital to which they were admitted, but in an identical-looking hospital in a different part of the country.
We feel a sinking sense of creepiness in reading these descriptions, of the uncanny. For all these delusions have one thing in common: they are all scary mistakes relating to identity, whether the subject's own identity or that of others. The subject's beliefs violate our own heretofore-unquestioned beliefs about identity - that identity is stable, that its boundaries are those of a body#, that other people are really out there and are the same people they were a minute ago. The monothematic delusions represent specific breakdowns in our system for keeping identity straight. But in examining these breakdowns, we must gradually come to realize what it means: our system for recognizing ourselves and others, for keeping the characters in our stories straight, is a physical, biological system, just like our eyes. Our perception of identity is, to a large extent, direct perception. There is no longer a safe "self" nestled inside our brains, reaching out into the world through (sometimes faulty) sensory equipment; even the self itself is made of sensory equipment, which by its nature may be innacurate.
Perhaps when we perceive ourselves and others, we are not perceiving something real, but we are watching our brains constantly manufacturing an illusion.
The monothematic delusions are scary because they force upon us the realization that we perceive identity the way we perceive color: directly and without reason's assistance.
Now the difficult task of the non-delusional person, who perceives his own identity and that of others with as much clarity as he perceives the blueness of a clean sky, is to nonetheless realize that selves and identity do not really exist, but are constructed by the elaborate brain he has the sense of occupying.
In the discipline of psychology, delusion is defined in contrast to the beliefs that exist in the background culture. When being tested for delusion, one is being tested not against some abstract standard of veracity, but against the perceptions of the majority. But we must wonder: even if almost all of the thermometers in a room read 72 degrees, does that really make it 72 degrees inside? Could all those thermometers be wrong together? (Perhaps because they all malfunctioned in the same way?)
Underlying the perception of identity is the brain's capacity for face recognition. Since organic brain damage may result in the loss of the ability to recognize objects, but not faces, or faces, but not objects, it is believed that there is a whole separate machinery in the brain dedicated to nothing but processing faces. The quickest glance at a person's face allows us to immediately perceive the person's identity, sex, mood, age, race, and direction of attention, all crucial information for social animals (Tsao, 2008).
An interesting observation about our facial recognition machinery is that we recognize caricatures (cartoonish portraits exaggerating unusual features) better than we recognize the actual faces that the caricatures represent. Some researchers suggest that this might mean there is a sort of hard-coded "prototypical face" in our brains to which we compare all other faces (Leopold, 2001); others suggest that there is no neutral "norm face" seared into our brains, but rather that we each form our own norm face prototypes based on the faces we are exposed to (Lewis, 1999). (This latter explanation would make sense of the fact that people can generally recognize members of the race of people we were raised among better than members of another race.)
When human faces are rendered in art, they may be endowed with varying degrees of detail, from photorealism to cartoonish minimalism. The drawn heroes of comics are often rendered with especially little detail; Scott McCloud, in Understanding Comics, suggests that this kind of minimally-sketched, cartoonish face, bare of anything but expression elementals (eyes, eyebrows, mouth), is easier for us to identify with than a more detailed, specific representation of the character (McCloud, 1993). It is as if all we need to mentally render the character, to imagine it having an inner life like our own, are the most basic cues to facial expression.
The fact that cartoons are so easy for us to process into meaningful representations of beings (with inner lives) suggests that our facial recognition processes, perhaps even our keeping-identity-straight processes, are themselves cartoonish. We focus on certain information and the rest is elided. And that's the scary part: we don't perceive this elision. With our fragile but self-important conscious awareness, it is as if we have bright flashlights strapped to our heads, so that everywhere we look is well-lit; meanwhile all around us things squirm in the darkness outside of our perception.
Our mechanisms of perception are some of those dark, squirming things. Visual blind spots are well-studied. But there are analogous blind spots in the perception of identity.
The perception of identity, of ourselves and others, underlies not only ethics but all meaning that we perceive or impose. Everything that is important to us rests on a foundation of the perception of ourselves and others as experiencing beings, with personalities and histories and roles to play within our stories.
Stories themselves may be thought of as a kind of cognitive bias. We imagine ourselves in stories to give our actions and relationships a context within which to be meaningful. Creating an internal narrative is the essential function of the conscious self, and one's internal narrative is by definition what feels most real to the individual. But narrative is itself a kind of primary perception, rather than a process of reason; the person experiencing the Capgras delusion creates the doppelganger-replacement story not through conscious, rational processes, but rather driven by the need to come up with an (emotionally) acceptable explanation for the primary perceptions of face recognition minus appropriate emotion. Believing our own narratives is like the colorblind individual believing his color blindness.
However, the colorblind individual has a strong reason to deny that his perception reflects objective reality: the testimony of those around him. Perhaps the highest-level rational process of all, in humans, is "check your conclusions against those of your peers." The colorblind individual who can (at least intellectually) admit that his perception of colors in inaccurate assures us that he is still one of us - despite his perceptual difference, he can function as our epistemic peer. His mind is working. What worries us most about the Capgras individual is not so much that his brain is "wired" wrong - it's that he will not change his beliefs when confronted by the testimony of others. If he has no "insight," as psychologists call the ability to perceive one's own mental malfunction, it is as if he has no mind - there is, clearly, no "self" safely ensconced inside his brain for us to relate to. So, perhaps the Capgras individual has lost his ability to rationally weigh the testimony of others. Or perhaps his sense that people are not who they seem is so intense and undeniable as to weigh a hundred times heavier, to him, than even visual perception (as those with merely visual disorders generally have insight into their condition).
It is extremely difficult to maintain a belief or set of beliefs when not surrounded by others who share those beliefs. In the laboratory, subjects will fail to report their true perceptions, and instead report that they share the reported perceptions of the group - especially when the task is defined as important (Baron, 1996). In the real world, religious people who leave their communities generally alter their beliefs toward those of their new communities. Agreement, not truth, is the most important function of a human brain, as Vonnegut suggests in Breakfast of Champions (though this insight is not limited to women):
Patty Keene was stupid on purpose, which was the case with most women in Midland City. The women all had big minds because they were big animals, but they did not use them much for this reason: unusual ideas could make enemies, and the women, if they were going to achieve any sort of comfort and safety, needed all the friends they could get.
So, in the interests of survival, they trained themselves to be agreeing machines instead of thinking machines. All their minds had to do was to discover what other people were thinking, and then they thought that, too. (Vonnegut, 1973)
Vonnegut invites us to consider the adaptive advantage of agreeing with our fellows, even if our fellows are wrong. But in addition to the motive to avoid violence, agreement might also enable us to communicate effectively in the first place. Agreement on basic matters is essential to the use of language. The messages we pass each other in language are short and dense and require a whole world of shared context to be understood. (This is why language that is to be interpreted hostilely, such as legal language, is notoriously incomprehensible: mutual context-assumption serves comprehensibility.) Something as basic as the identity of people must be assumed in order to understand what others are talking about.
We must understand the convincingness, the undeniability, of the Capgras individual's delusional perception of identity in order to understand our own white-knuckle death grip on our non-delusional perception of identity. For the Capgras delusional individual experiences opposite processes: perceptive pressure toward believing his delusion, and social pressure to deny it. Not so for the rest of us. For non-delusional perception - ordinary, neurotypical perception - perceptive pressure and social pressure align to enforce belief. That's great - as long as perception reports reality. If there are instances in which individuals almost all perceive wrongly, and there is no widely compelling explanation as to why (as with optical illusions), we are screwed. This process would be expected to fail to report reality in certain situations, leaving us with incorrect beliefs and no clear way to identify and correct them. We might expect misperceptions of a foundational nature to be even more difficult to correct than more superficial counterfactual perceptions.
Science (a sort of "beginner's mind" toward the world) suggests that our alleged selves do not possess the properties they are almost universally perceived to have (such as existing separately from, and on a higher level than, sensory perception). It is exciting for intellectuals to suggest the same. But in practical terms - in social terms - we cannot do other than to assume the existence of the perceived self. We can prove, but never know, that regarding the self, the only part that is real is the feeling of it.
Baron, Robert S.; Vandello, Joseph A., Brunsman, Bethany. "The forgotten variable in conformity research: Impact of task importance on social influence.". Journal of Personality and Social Psychology 71 (5): 915–927 (Jan. 1, 1996).
Hirstein, William, and V. S. Ramachandran. "Capgras Syndrome: A Novel Probe for Understanding the Neural Representation of the Identity and Familiarity of Persons." Proceedings: Biological Sciences, Volume 264, Issue 1380 (Mar. 22, 1997), 437-444.
Elliot, Carl. "A New Way to be Mad." The Atlantic (December 2000).
Leopold, D. A., O’Toole, A. J., Vetter, T., & Blanz, V. (2001). Prototype-referenced shape encoding revealed by high-level aftereffects. Nat Neurosci, 4(1), 89–94.
Lewis, M. B., & Johnston, R. A. (1999). A uniﬁed account of the effects of caricaturing faces. Vis Cognit, 6, 1–41.
McCloud, Scott. Understanding Comics. Northampton, MA: Kitchen Sink Press, Inc., 1993.
Monothematic delusions. (n.d.). In Wikipedia. Retrieved November 3, 2011, from http://en.wikipedia.org/wiki/Monothematic_delusion.
Vallar, G., and R. Ronchi. "Somatoparaphrenia: a body delusion. A review of the neuropsychological literature." Exp Brain Res. 2009 Jan;192(3):533-51.
Tsao, Doris Y., and Margaret S. Livingstone. "Mechanisms of face perception." Annu Rev Neurosci. 2008; 31: 411–437.