Three kinds of self-models
- Physical body model. This is a model of the physical body, with joints, bones, meat, weight, velocity, shape, etc. It is put into a model of the physical world, and it cannot occupy the same volume as other solids. So for example, the arm of the body cannot sink into the desk.
- Astral body model. This model has the same shape as the physical body model. However, it has no weight, is not affected by gravity, has no organs, and though it has a volume, it cannot exclude anything else from the volume (it's like turning off collision in a game). It is basically a ghost in the shell of the physical body model. It is usually a bit smaller than the physical body model.
- Viewpoint model. A point in space augmented with a Cartesian frame, to represent the orientation of your viewpoint. It represents your "true location". It is perched between the eyes of the astral body model, facing straight forward.
It is used to model where the sound you are hearing is coming from. So for example, if you hear a noise on the left, that would be modeled as a sound source to the left of the viewpoint.
It is also used to model where what you are seeing is. So for example, if you see a ball straight ahead, that is modelled as a ball straight ahead of the viewpoint.
Note that even in a blind-deaf person, there is still a viewpoint model. It is simply not used to assist in inference of audio and visual input. Even a blind-deaf person must feel like they are somewhere in spacetime. That "somewhere" is the location of the viewpoint model within the world model.
These three self-models are meant to synthesize different kinds of sensory data. Here, I am speculating since I can't find papers about this.
- Physical body model synthesizes sensory input on the body: location of localized pain, heat, coldness, touch, pressure.
- Astral body model synthesizes proprioceptive input, vestibular input, and active motor output.
- Viewpoint model synthesizes location of visual and auditory sources. Basically, if you hear something from the left, and sees something
Your viewpoint model is updated continuously by sensory input. There is a constant inference loop between your viewpoint model and the visual sources and audio sources in the world model, as your brain tries to integrate all visual, auditory, vestibular, and other senses into one consistent model of the world with a viewpoint. - If the ear senses an acceleration upwards, that would tend to move your viewpoint model up.
- If the eye sees most of the scenery moving to the right, that would tend to move your viewpoint model to the left, or turn it to the left.
- If the eye sees most of the scenery staying still, but a small blob moving to the right, you would keep your viewpoint model stable, but move the model of the blob.
The art of ventriloquism is all about confusing the viewpoint model, so that the sound source is incorrectly modelled.
Case studies
Blanke, O., Arzy, S., & Landis, T. (2008). Illusory reduplications of the human body and self. Handbook of Clinical Neurology, 429–458. doi:10.1016/s0072-9752(07)88022-5.
The main forms of doubles are the visual own-body reduplications: autoscopic hallucination, heautoscopy, and out-of-body experience (out-of-body experience) as well as the rarer forms including polyopic heautoscopy and inner heautoscopy. These are referred to here as visual doubles. Other own body reduplications include feeling of a presence (sensorimotor doubles), hearing of a presence (auditory doubles), and negative heautoscopy (negative doubles).
Simple autoscopy
the patient suddenly noticed a seated figure on the left. ‘It wasn’t hard to realize that it was I myself who was sitting there. I looked younger and fresher than I do now. My double smiled at me in a friendly way
OBE induced by brain electric stimulation of the right temporoparietal junction:
During these out-of-body experiences the patient experienced that she was localized under the ceiling almost as if touching the ceiling with ‘her’ back and looking down on her (autoscopic) body that was lying motionless on the bed. All stimulations at this current intensity were associated with an instantaneous feeling of ‘lightness’ and ‘floating’ about two meters above the bed. The elevated self was experienced as a complete body, although the patient was only sure about the presence of trunk, head, and shoulders. Repeated stimulations induced identical out-of-body experiences in the intrigued and surprised patient who had never experienced an out-of-body experience previously. With respect to the autoscopic body the patient reported that ‘I see myself lying in bed, from above, but I only see my legs and lower trunk’ (i.e. negative heautoscopy). In addition to seeing her body and the bed, the patient experienced seeing the present physicians and the table next to the bed. The visual experience was described as highly realistic and not dreamlike. Initial stimulations at the same site, but with smaller currents (2.0–3.0 mA), induced vestibular responses, in which the patient reported that she was ‘sinking into the bed’ or that she has the impression of ‘falling from a height.’ Interestingly, if the patient was asked to look at certain parts of her body during focal electrical stimulation she experienced other illusory body part perceptions: if looking at her limbs that were stretched out during electrical stimulation (4.0–4.5 mA), she had the impression that the inspected body part was transformed, leading to the illusory visual perception of limb shortening. If the limbs were bent at the elbow or knee she reported that her legs appeared to be moving quickly towards her face, and took evasive action (K4.0–5.0 mA). Finally, with closed eyes, the patient had neither an out-of-body experience nor visual body-part illusions but perceived her upper body as moving toward her legs (aesthetic illusion; 4.0–5.0 mA).
Persistent autoscopy for 3 months:
A 30-year-old, right-handed female reported seeing in a permanent fashion her own image as though she was looking into a mirror. Wherever she looked, this mirror image was always in front of her, at a distance of about one meter. If a solid object was placed between the autoscopic image and the patient, she said that she can still see the image, but nearer to her, on the surface of the object. She described that the autoscopic image was transparent, yet somewhat blurred, setting ‘on a sheet of glass’ resting against whatever object she was looking at. The image was life-sized and usually included head and shoulders, but could extend as far as the legs if the patient explored it by moving the gaze downward over the figure. It was always dressed exactly like the patient. Like a real mirror image, the autoscopic image or body replicated her bodily movements, in particular her face and arm movements. Interestingly, while one of the examiners put his hand on the patient’s shoulder the patient reported that she could perceive something on the image’s shoulder similar to a hand. The image disappeared when she closed her eyes. The autoscopic hallucination was not associated with an emotional state and the patient appeared somewhat indifferent to its presence and disappeared progressively after 3 months.
Heautoscopy:
‘[The patient] has the immediate impression as if she were seeing herself from behind herself. She felt as if she were ‘standing at the foot of my bed and looking down at myself.’ Yet, [...] the patient also has the impression of ‘seeing’ from her physical [or bodily] visuospatial perspective, which looked at the wall immediately in front of her. Asked at which of these two positions she thinks herself to be, she answered that ‘I am at both positions at the same time.’’
Heautoscopy, epilepsy, and suicide (1994):
Heautoscopy is a common theme in fiction and the appearance of the double often announces the hero's death-which is usually a death by suicide. Probably the most dramatic illustration is Edgar Allan Poe's "William Wilson" who, in an attempt to stab his double, kills himself. But also Oscar Wilde (The portrait of Dorian Gray), Franz Werfel (Spiegelmensch) and Friedrich von Gerstacker (Der doppelganger) had their heroes commit suicide to escape the horror of being haunted by their second selves. In Fjodor Dostoyevsky's famous novel The double, the protagonist's first heautoscopic experience coincides with his contemplation of suicide by drowning and the hero in Guy de Maupassant's Le horla, after having attempted to murder his own double, reaches the conclusion: "No . . . no . . ., he is not dead. I suppose then, I have to kill myself!"
Some of these authors have not only had epilepsy but have also known heautoscopy from personal experience.
Heautoscopy, in particular in its association with seizures, is commonly accompanied by intense feelings of horror or despair.
The first non-fictional account of suicide as a consequence of heautoscopy may be the case of a man who day and night felt persecuted by his doppelganger until he shot himself to get rid of it.
One intriguing example is that of a young man who, apart from heautoscopy, described sensory and mental phenomena strongly reminiscent of a temporal lobe epileptic process.' In one particular heautoscopic episode he saw and at the same time felt himself falling from a mountain during an attempt to commit suicide. Four years later he was found dead at the foot of a high rock. A patient of Lukianowicz's was less scared by his epileptic fits than by the frequent appearance of his double. He was afraid of going mad and had repeatedly compared himself with the hero in Maupassant's Le horla. One day he walked straight into an electric streetcar and was killed on the spot.' A 40 year old nurse had tonic-clonic seizures since her schooldays. Her attacks were regularly preceded by heautoscopy and a steadily increasing feeling of futility and misery that led her to think about suicide. She later killed herself.
Accidental suicide attempt:
A 21 year old right handed man had an uneventful medical history until age 15, when he developed complex partial seizures.... The patient stopped his phenytoin medication, drank several glasses of beer, stayed in bed the whole of the next day, and in the evening he was found mumbling and confused below an almost completely destroyed large bush just under the window of his room on the third floor. At the local hospital, thoracic and pelvic contusions as well as multiple bruises were noted.
The patient gave the following account of the episode: on the respective morning he got up with a dizzy feeling. Turning around, he saw himself still lying in bed. He became angry about "this guy who I knew was myself and who would not get up and thus risked being late at work". He tried to wake the body in the bed first by shouting at it; then by trying to shake it and then repeatedly jumping on his alter ego in the bed. The lying body showed no reaction. Only then did the patient begin to be puzzled about his double existence and become more and more scared by the fact that he could no longer tell which of the two he really was. Several times his bodily awareness switched from the one standing upright to the one still lying in bed; when in the lying in bed mode he felt quite awake but completely paralysed and scared by the figure of himself bending over and beating him. His only intention was to become one person again and, looking out of the window (from where he could still see his body lying in bed), he suddenly decided to jump out "in order to stop the intolerable feeling of being divided in two". At the same time, he hoped that "this really desperate action would frighten the one in bed and thus urge him to merge with me again". The next thing he remembers is waking up in pain in the hospital.
The striking case of prophetic heautoscopy is taken from Lemaitre A. Un accident mortel imputable a l'autoscopie (1904). The patient died at 21 in 1904.
Dans une étude sur les Hallucinations autoscopiques j’ai précisément raconté des phases curieuses de dédoublem ent, auquel X était sujet, celle-ci entre autres qui date du 8 août 1901, alors qu’il était accoudé à une fenêtre:
« Je me vis transporte au pied de la montagne et j'éprouvai la sensation que j'avais voulu me détruire et que je m'étais précipité du haut d'un rocher. Mes membres étaient meurtris, brisés; je voyais et sentais mon sang couler et je m'affaiblissais. Je tenais à mourir et pourtant je le regrettais à cause de ma jeunesse, mais d’oà vient cette continuelle tristesse ? J’aimerais mieux mourir une fois pour toutes que de me sentir comme cela mourir si souvent... » etc.
Se sentir m ourir trois ans d’avance, au bas d’un rocher, les membres m eurtris et sanglants ; éprouver cela, non pas une fois, mais fréquemment, dans des crises autoscopiques,... cela donne à réfléchir!
Voilà bien des années que X disait à qui voulait l'entendre, et com bien souvent à moi-même, qu’il mourrait à 21 ans.
Rough translation:
In a study on autoscopic hallucinations, I specifically recounted curious phases of duplication, to which X was subject, this one among others which dates from August 8, 1901, when he was leaning on a window:
“I saw myself transported to the foot of the mountain and I experienced the sensation that I had wanted to destroy myself and that I had rushed from the top of a rock. My limbs were bruised, broken; I saw and felt my blood flow and I weakened. I wanted to die and yet regretted it because of my youth, but where does this continual sadness come from? I'd rather die once and for all than feel like this dying so often ... "etc.
Feeling dying three years in advance, at the foot of a rock, limbs bruised and bloody; to experience this, not once, but frequently, in autoscopic seizures, ... it is sobering!
For years X had told anyone who would listen, and often myself, that he would die at 21.
Aristotle's record on autoscopy:
Such was the case of a man whose sight was faint and indistinct. He always saw an image in front of him and facing him as he walked.
Internal autoscopy (1992) in an Indian patient:
During interview, patient reported that he could "see" his brain as a lotus coloured pinkish mass of flesh with grooves and bulges. He further stated that it was covered by a layer of smoke. He expressed surprise over this phenomenon agreeing that it is impossible...
LUKIANOWICZ, N. (1958). Autoscopic Phenomena:
Mrs. A, a retired school teacher, aged 56, had experienced autoscopic hallucinations since her husband's funeral. When she returned home from the cemetery and opened the door to her bedroom, she immediately became aware of the presence of somebody else in the room. In the twilight of the late afternoon she noticed a lady in front of her. Mrs. A. lifted her right hand to turn on the light. The strange lady made the same movement with her left hand, and thus their hands met. Mrs. A. felt cold in her right hand and experienced a sensation as if all blood ran out of her hand. Under the electric light she noticed that the stranger wore an exact replica of her own coat, hat, and veil. In spite of this unusual situation, Mrs. A. was neither surprised nor afraid. She "felt deprived of any feeling," and, without bothering any more about the intruder, she began to undress and took off her veil, her hat, and her coat. The lady in black did exactly the same. Only then looking into the stranger's face, did Mrs. A. become aware that it was she herself staring at herself, as if in a mirror, and mimicking her own movements and gestures. It occurred to her that it was her "double," her "second self," looking at her. She felt that it was more alive and warm than she was herself. Feeling extremely tired and weary, she lay down on her bed. As soon as she closed her eyes, she lost the sight of her apparition. Almost at once she felt stronger, as if "the life of this astral body" was coming back into her own body. Soon she was fit to get up, to change her dress, and later to have her supper.
Since that evening she had been visited almost daily by her "astral body," as she used to call it, mostly at dusk, when she was on her own. She would see it only when she looked straight, and would lose sight of it as soon as she turned her gaze sideward or up or down. She would also make her double disappear by closing her eyes, but it would reappear after a while. Then, with her eyes closed, Mrs. A. would "see" her phantom just in front of herself with its eyes closed. Yet the double would open its eyes again as soon as Mrs. A. opened hers. The image was life-sized. The most distinct part of it was its face, torso, and hands; the lower part of the trunk and the legs were less sharply delineated. They were rather "misty" and "as if they were transparent." Yet the patient "knew and felt" the exact position in space of the phantom's legs at any time (kinesthetic perception). Soon she noticed that whenever she experienced her autoscopic hallucination, she "felt mildly amazed and bewildered" and had "a perplexing feeling of unreality."
The electric car suicide case:
Mr. B., aged 38, an architect, separated from his wife, had had an artificial limb since 1919, when, at the age of 25, his right leg was amputated just above the knee, after complete destruction of the knee joint by a grenade. Eight years later he developed epileptic attacks, preceded by a sensory aura in the form of excruciating pain in his nonexisting limb. In this respect he resembles the interesting case of Cohen,10 whose patient referred his cardiac pain of coronary occlusion to his left (phantom) arm. The fits were diurnal in type and occurred at about 11 a. m. Thanks to their unusual regularity, the patient was able to organize his life so as not to be socially embarrassed or endangered by his fits.
He experienced his first autoscopic hallucination five years after the onset of his epilepsy. Sitting in his study and discussing some plans with his builder-contractor, he suddenly felt "very sad and weary." He stopped talking and turned his head to the door leading into his study. There he saw a tall man, dressed in a replica of his own suit, wearing a monocle in his right eye (which Mr. B. wore at that particular moment), come, like a "semitransparent mass," through the closed door and slowly approach his desk. "The phantom was absolutely identical with me," reported B. later, "but for one detail : It did not show the slight limp I always have because of my prosthesis." As the apparition approached the desk, Mr. B. "felt like paralyzed. I could not move. I felt as if all my life left my body and went into him." Then he apparently lost consciousness, though only for a few seconds, and no motor phenomena were observed by the builder sitting across the table. All he noticed was an unusual pallor on his employer's face and a vacant expression. Here is the builder's verbatim report : "When I asked Mr. B. if he did not feel well, he did not answer. He was staring at the door and seemed not to hear me. After a second or two he got up, walked to the door, and tried the handle. He then came back to his desk, looked at me, and said: 'Yes, Mr. P. Where were we? O, yes, I know,' and he carried on with his explanations just from the very point where he had stopped a minute ago. Yet he was not in his usual form : He had difficulties in expressing himself and, after a minute or two, broke off altogether, asking me to call again later. I could see that he was not at all well and that he wanted to get rid of me."
The patient gave this retrospective account of the events : "I and my double melted together into one body and one soul. Everything became at once so lifeless, empty, and meaningless, so unreal, and so far away. I do not know how long it lasted, but it seemed ages to me. Finally, 'he' left my body again, and I saw him walking slowly toward the door. On this occasion he was limping on his right leg, as I always do, and somehow I knew that he felt tired and weary. He disappeared through the closed door, without opening it. Then suddenly I felt an irresistible urge to go over to the door and to satisfy myself that it was really closed. I do not know why I did it. It was like carrying out a posthypnotic command. After this experience I felt weary and tired, and much older. I had difficulties in finding the right words and could not continue to discuss the technical points with my contractor. So I sent him away, and, as I felt headachy and sleepy, I went to my bedroom and lay down. I fell asleep, but woke up in a little while feeling fresh and fit again."
Mr. B. had altogether five such experiences, all of them in his study, all at the same time of day, almost exactly at 11 a. m. (he used to point out that this was the time when he had lost his leg in battle). After his fifth autoscopic incident, the patient became alarmed. He kept thinking of Maupassant's "La Horla," and was afraid that he himself was "getting mad." He went to Vienna, accompanied by his sister, to consult Professor Poetzl [Otto Pötzl]. On his arrival at the Staats-Bahnhof in Vienna, Mr. B. walked straight onto an oncoming electric tramcar, before his sister could grab and stop him. He was killed on the spot. According to his sister, "he was though in a trance and absolutely oblivious of his environment."
Polyopic heautoscopy:
Polyopic autoscopic hallucination or polyopic heautoscopy is present when patients report seeing more than one autoscopic double in extracorporeal space, that is, a multiple rather than a single reduplication of one’s own body. Probably the first account of polyopic heautoscopy is to be found in Mueller’s (1826) seminal work on visual hallucinations. Returning home late from work, this exhausted university professor suddenly found himself in front of 15 persons, all clearly recognized as doubles of himself although being of different ages and wearing different clothes he himself had used to wear in former times (quoted after Brugger et al., 2005)... In a third of the cases autoscopic phenomena were characterized by either two or three doubles, but most often by a large number of doubles that, in some cases, filled up the entire room or the interior of the patient’s body. If polyopic autoscopic phenomena are characterized by a large number of doubles they are generally seen as quite small in size, whereas the cases with a smaller number of doubles are mostly experienced as having the same size as the patient. Echopraxia (or sharing of action between the autoscopic bodies and the patient’s body) was noted by two previously reported patients with autoscopic phenomena. The doubles are generally localized in the central visual field (lateralization in the visual field was only described by three patients). If mentioned, the perceived distance of the double from the patient was generally very small...
Polyopic Heautoscopy: Case Report and Review of the Literature (2006):
- Psychotic, depressed patient sees a crying double of herself. She closes her eyes, and, after reopening them, sees the entire room crowded with doubles, all identically looking and all crying.
- Schizophrenic patient sees “seven forms coming out of me, one after the other [...]. They all looked like me; they did what I had in my thoughts”
- Patient identifies himself with a motionless giant double on which many additional but tiny doubles are climbing around.
- Healthy (during puerperium): Patient sees a non-pregnant double straight ahead of herself. A second double covers her body “like a mask but [is] separated from it by a thin layer”.
- “Five or six” doubles imitate the patient’s actions she herself had performed “a short time beforehand”
- Patient feels split into three persons. The actual self observes two other selves represented by the left and right body halves, respectively
- Patient sees multiple mirror images of herself in different sizes. Autoscopic images are localized in the interior of the patient’s body.
- In his left visual field, the patient sees “crowds of tiny figures [head and shoulders, only], all the colors of the rainbow – all myself”
Inner heautoscopy:
Patients with inner heautoscopy claim to see their inner organs in extracorporeal space (Bain, 1903; Sollier, 1903a; 1903b) or rarely within their own body from an extracorporeal visuospatial perspective (Heintel, 1965). Modern accounts of inner heautoscopy are rare (Carlson, 1977, case #4; Magri and Mocchetti, 1967; Peto, 1969). Internal heautoscopy may also be encountered during shamanic rituals (Eliade, 1951/ 1964, p. 62; cited in Brugger et al., 1997) and has been reported in certain populations. (Irwin, 1985 reported that Eskimos see their body as a skeleton under certain conditions). With respect to medical reports, Comar (1901; case #1) described an 18-year-old female patient who reported seeing her heart, and another patient (case #2) who claimed seeing her hip joint. Brugger et al. (1997) described a patient who saw the interior of his torso, including blood circulating in vessels and another patient who saw his skeleton. The case described by Heintel (1965) is interesting as she did not describe seeing her inner organs in extracorporeal space, but many different mirror images of her own body (of different sizes) inside her body. It thus seems as if this patient experienced seeing doubles inside her body from a disembodied visuospatial perspective that is generally reported by subjects with an out-of-body experience.
... a patient claiming to see at different times her heart, lungs, intestines, uterus, muscles, and even her brain (Sollier, 1903a, pp. 68–79).
This might be caused by internal surgery, similar to phantom limbs are caused by removing limbs.
... not only the amputation of a limb, but also the resection of inner organs such as uterus, stomach, and rectum may lead to phantom sensations for the removed inner organs. Inner heautoscopy may thus be considered a visualized phantom sensation for inner organs, due to disturbed central mechanisms with respect to visceral own body representations...
Feeling of a presence: hallucinated feeling that somebody is close by, although they do not visually hallucinate that person.
This experience of feeling another human person close by is often described as highly realistic and vivid, but may also be experienced as dreamlike and ephemeral. It is mostly a transient experience, yet might sustain for a longer time. It often disappears when patients try to ascertain themselves that there is ‘nobody there’ by looking towards the felt location of the ‘presence.’
A 55-year-old right-handed woman reported several times a day the brief sensation of having ‘a shadow’ in her right peripersonal space. She described that ‘the shadow is always in front of me, about 50 cm to the right. I feel that it is very familiar to me, and I kind of know that it is a male shadow.’ She did not see the shadow yet she could ‘feel’ it, although she knew that there is nothing there. The shadow was described as stable or stationary, was not experienced as performing any action, did not talk to the patient and never imitated the patient’s movements. The experience was not occurring during or after the patient’s epileptic seizures. Often the feeling of a presence was associated by feelings of dizziness, vertigo, and headache. Notably, while her husband died some month afterwards, the patient began to refer to the presence as her deceased husband.
Negative heautoscopy:
Negative heautoscopy refers to failure to perceive one’s own body either in a mirror or when looked at directly. Given the rarity of negative heautoscopy for the entire body we detail here the experience of a recently reported patient in whom negative heautoscopy only affected one extremity. We suggest that the involved pathomechanisms are similar and might further relate to those involved in asomatognosia.
The most well-known description has probably been given by Guy de Maupassant in his short story ‘Le Horla’ (Maupassant, 1886/1961) and was quoted by Lhermitte, Critchley, and many other neurological authors. After describing many instances of persecution, fear, and hallucinations Maupassant writes:
‘I could not see myself in the mirror! It was empty, transparent, deep [...] I was not reflected in it [...] and I was standing in front of it.’
A medical report with negative heautoscopy has been described by von Stockert (1934). This patient was ‘alarmed by the sudden impression of the left half of his body being absent. When he would look at himself with horror, he would indeed notice that the left half was not there. At these moments he felt somewhat comforted by the visual confirmation [of not seeing his left body] of his somatosensory impressions’ (cited in Brugger et al., 1997). Interestingly, this patient claimed not only that he could no longer see his own left body half, but also noted that, when looking at other people that they lacked the right side of their bodies.
Indeed, Gloning et al. (1954) described a patient with simple partial seizures and left-sided sensorimotor deficits who noted that during his simple partial seizures his right body half was one meter in front of his normally localized left-sided body. Brugger et al. (2006) describe a patient who noticed that his body was split along the midline with an empty area between both body parts. Finally, Blanke et al. (2002; 2004) described a patient who during an out-of-body experience only saw the lower parts of her body (autoscopic body).
This 51-year-old female patient stated that she could not see-for several minutes—her left arm and forearm anymore, while she clearly saw all other parts of her body. Interestingly she could also see the part of the table that should have been hidden by her left arm and hand. Negative heautoscopy disappeared progressively as the arm and hand were experienced to be restored progressively.
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