Quote from wiki: "In psychology, bicameralism is a controversial theory which argues that the human brain once assumed a state known as a bicameral mind in which cognitive functions are divided between one part of the brain which appears to be "speaking," and a second part which listens and obeys."
In my letter I try to describe my experience and because of the need to understand I also try to explain my experience. Among other things I wonder if divided attention between listening and "speaking" is a core feature that may result in many of the symptoms of schizophrenia if to much attention is devoted to the nonverbal aspects of speech...
My letter including some soundfiles, all the changes and more information about my experience and how I try to understand it: http://www.freewebs.com/stefan661/
I come from Sweden and was diagnosed with paranoid schizophrenia seven years ago. I have been hearing voices most of the time and when it was most severe I heard ALL of my thoughts. That is I heard voices that were experienced as alien as well as my own voice (perceived as my own thoughts spoken out "loud;" this is called "gedankenlautwerden"). When I donÂ´t hear my verbal thoughts IÂ´m normally aware of that I imagine the movements needed to produce different speech sounds and at the same time IÂ´m aware of where in my mouth different speech sounds would be produced. To me covert speech (verbal thoughts) and overt speech (when you talk) are very similar in this way. When my thoughts are alien IÂ´m not aware of the "formation" of the words nor am I aware of where in my mouth different speech sounds would be produced. Finally if I hear what is percieved as my own thoughts I imagine how the words would be produced, but still different speech sounds are percieved as coming from a source outside my head. The latter phenomenon has enabled a better understanding of what is going on and I want to share my experience and understanding of the voices I hear. ( I started to hear voices when both my parents were seriously ill and later the same year died. Now IÂ´m "OK" and believe that my voices are my own thoughts heard out "loud" due to "abnormal" speech perception (and maybe thatÂ´s one reason why they have no names). The voices I hear is probably simply what I imagine that other people (who I donÂ´t recognise) would say although sometimes a bit distorted and hard to hear. This is my approach when I hear voices, but it has not always been easy. Gradually IÂ´m learning to deal with this and of course I respect other peoples believes and understanding of the voices they hear and hope that I donÂ´t offend anybody when I try to understand things like why verbal thoughts become alien and heard out "loud". I have sent one version of this letter to several scientists because I wonder what they might think of my attempt to try to understand some aspects of the voices I hear. Their response is very important to me because I donÂ´t want to believe in this if it according to their knowledge is wrong and of course then I hope they have an alternative explanation to some of my observations concerning functional auditory hallucinations.)
Before you read this it is important that you know that IÂ´m not used to expressing myself in English and when I write vocal tone in this letter I mean the sound you produce when you press air through your vocal cords and they start to vibrate with a certain frequency. When I write vocal tone I only mean what you hear when you do like that and not the more verbal aspects of overt speech (when you speak) and covert speech (when of course you only imagine the vocal tone of your inner voice. The difference when you hear functional auditory hallucinations is that you attend a real non verbal sound that substitute the vocal tone of your inner voice.). ItÂ´s a bit lazy of me not to include the sources I have used and this and the soundfiles I refer to will be included when I have resolved the more urgent problems I have with the translation of different words and English in general.)
"In schizophrenia, functional hallucinations are defined as those that occur when a patient simultaneously receives a real stimulus in the perceptual field concerned (e.g., hallucinated voices heard simultaneously withâ€”and specific toâ€”the real sound of running water)"
My Own Thoughts Spoken "Out Loud" (gedankenlautwerden)
For instance I could listen to a smooth sound of low volume (coming from the surroundings or recorded to ensure that there were no changes in volume) and notice that my focus on this sound was enhanced when my inner voice articulated a single vowel speech sound resulting in a subjectively perceived change in volume correlated to the perception of an auditory vowel illusion. All speech sounds that include the vocal tone of the voice are heard like this. The same thing did not happen when I listened to this sound and used my inner voice to express a single stop sound or a certain consonant without the vocal tone of my inner voice. (I assume that I failed to do this ("t") and used the vocal tune of my inner voice ("te") when I heard a speech sound with the vocal tone ("te"). Certain speech sounds without the vocal tone of the voice that to some degree match "white noise" might be an exception because sometimes I could hear them to, but I am uncertain if I used the vocal tone as a "carrier". In speech perception you talk about top-down and bottom-up perceptions...) Still strangely these speech sounds are incorporated in the perceived voice when combined with vowel sounds. If I imagine the letter t as "t" I donÂ´t hear anything, but if I imagine the letter t as "te" I hear both t and e. This observation makes it possible to understand how the illusion of speech sounds that you pronounce without the vocal tone of the voice are included. As you might expect they are perceived in the end or beginning of each subjectively or objectively (sometimes the case especially when the heard voice is alien) perceived change in volume. Every subjectively perceived change in volume modified and controlled by the vocal tone of my inner voice is "dressed up" with all the speech sounds included in each syllable and hereby every syllable correlates to a certain momentary change in volume. (Recent research suggest that "the brain samples the incoming speech in "chunks" that are about the length of a syllable from any given language".) The consequence of that my attention was guided by all the vocal tone sounds of inner speech was that the sound no longer was perceived as smooth. Instead it was subjectively perceived with the same changes in volume that a distant voice of the real world would produce (and what more sometimes when I imagined a female voice as my own I attended a different sound that could match such a voice. This didnÂ´t always happen on the contrary when my own voice was more neutral it was more vulnerable to become heard out "loud" and it never happened if I with "my" inner voice repeated the exact memory of something somebody else had just told me. This last observation might be the result of that you repeat a voice that has its own rhythm and vocal tone which decreases the risk of interference if no external stimuli match the short term memory that controls your attention.).
To ensure that you understood what I wrote in the last paragraph I will try to express myself in other words. What happens is that the vocal tone of my inner voice is substituted by an external sound which like when the voice is alien results in a concrete sensoric sound image. To make a concrete sensoric sound image possible synchronization of the vocal tone of my inner voice with a smooth sound must occur. (With the help of "attention modification" a smooth sound of low volume is subjectively perceived as if the volume was changing in synchronicity with the vocal tone of the inner voice.) To understand the synchronized incorporation of the verbal content you have to know that my attention was guided by the vocal tones in different speech sounds of my inner voice and I only heard the illusion of a vowel speech sound or the illusion of another speech sound that included the vocal tone of the inner voice when a momentary increase in attention occurred. (What you hear when your attention momentary is increased is a vowel speech sound or another speech sound that include the vocal tone of the voice pronounced with the same frequency or frequencies as the sound you attend.) To make the synchronized incorporation of the verbal content complete you also have to include the illusion of hearing speech sounds without the vocal tone of the inner voice. This is done when every subjectively perceived change in volume correlates to the perception of a syllable.
Maybe (IÂ´m not sure about this!) the closest you can come to experience what it feels like when your thoughts become "loud" is if you are humming the words while reading. If you do it right objectively you only hear the vocal tone of your voice, but somehow still, just like during gedankenlautwerden, the verbal content is associated with a non verbal sound that substitute the vocal tone of your inner voice. (At least the "humming"sound substitute the vocal tone of my inner voice when I do like this and I donÂ´t hear "gedankenlautwerden" anymore.) The verbal illusion when I heard my own thoughts was not always clear and maybe the biggest difference when you do like this is that the volume of the vocal tone is much higher than during gedankenlautwerden. If you donÂ´t hear an illusion when you do like this and hum the syllables at least to some degree the vocal tone of your humming voice is synchronized with the vocal tone of your inner voice and maybe, along with my attempt to describe my experience of "gedankenlautwerden", hopfully this makes it a bit easier to understand.
I think that the vocal tone of my inner voice is used to guide attention in the same way that a memory of a tone enables perception of the same tone at a lower volume than otherwise would be the case. This is what I mean when I talk about "attention modification" (resulting in a subjectively perceived change in volume and sometimes include that you disregard or donÂ´t attend an objective change in volume). Strangely the vocal tone of the inner voice also guide attention towards sounds that doesnÂ´t match the vocal tone of a human voice. (What is written in the next paragraph gives an understanding of how this might be done with the help of a short term memory.) IÂ´m convinced that knowledge of some aspects of the cocktail party effect could be useful to get a better understanding of functional auditory hallucinations. Among other things the cocktail party effect makes it possible to understand the subjectivity of the perception of volume mentioned in the attenuation model. (Three times higher than suppressed noise and maybe more when things go wrong and you hear voices. The subjective perception of volume could be understood if suppressed noise is the reference, but I wouldnÂ´t exclude the possibility that also the perception of volume is due to enhanced activation of primary auditory cortex with the help of a memory. To understand what happens when suppressed noise is the reference maybe you can compare with when you are sitting in a stationary train and the reference is a train on the adjacent track that begins to move, instead of the illusion that the volume of the voice increases a strong sensation that one's own train is moving in the opposite direction can be experienced.) People who donÂ´t hear voices often think itÂ´s quiet when maybe I and others who hear voices uses our memories to enable the perception (and interpretations) of external sounds that otherwise wouldnÂ´t be heard because of the low volume. Sometimes of course itÂ´s a question of internal sounds and "normal" auditory hallucinations, but probably not as often as people assume. (My experience tells me that my brain prefers to interpret external sounds and if the use of earplugs doesnÂ´t work I have to assume that the brain takes what it gets and instead maybe interprets internal sounds. (I have tinnitus and I am also more aware of internal sounds maybe due to lack of inhibition.) If I turn of all external sounds with my fingers while IÂ´m hearing a voice usually the verbal "message" will end (sadly only momentarily) and if it doesnÂ´t I can hear a difference. Sometimes this leads to that I experience the voice inside my head instead, but not always and although I recognise the voice the nature of the voice will usually change and become less "colored" by an external sound. I assume that failure to locate the source of a sound may lead to that you experience internal or external voices without any regards to the true spatial location of the sound you interpret.)
I assume that my brain uses a short term memory to modulate and keep track of a peripheral sound that substitute the vocal tone of my inner voice. (but of course if you hear a familiar voice a long term memory must also be involved.) To try to further confirm the assumption that memories guided my attention towards external sounds I first recorded a couple of notes comming from a violin in a certain sequence and after that I played them all together to see if I could single them out with the help of a short term memory. This actually worked and I heard the "melody" from the beginning of the tape over and over again. (Now I donÂ´t hear my own voice any more and maybe thatÂ´s why the intentional use of memories to control what to attend almost is lost. To call it intentional might give the wrong impression because sometimes when I heard the "melody" over and over again it was out of control and this was in a rather smooth sound.)
When listening I noticed a difference in attention between thoughts that were alien and other thoughts that were perceived as my own. It came clear to me that I gave more attention to a sound that was transformed into an alien voice than to a sound that made it possible to hear what was perceived as my own thoughts and if itÂ´s true it doesnÂ´t differ from what you would expect. I mean of course you pay more attention to what you hear if you think that somebody else tells you something concerning you than when you know whatÂ´s comming. Actually a couple of times I could change my own voice into an alien one by attending more to a sound, but only if it was not smooth. Many observations, with some difficulty also with recorded sounds, confirmed that the volume of the sound had to change almost like the vocal tone of a real voice if it were to be perceived as alien. If you understood what I wrote about my own voice you have the knowledge to understand how all the different speech sounds are incorporated in an alien voice. One difference is that an objectively perceived change in volume sometimes makes it impossible to control and hold back each syllable. (My theory is that several short increases in volume is needed to trigger the syllables of the voice because of the attention shift that follows every increase. My assumption is that the attention that is needed to control and hold back verbal thoughts is shifted to the "vocal tone" sound.) If attention increases further towards an external or internal sound it ought to be possible to hear an alien voice in a smooth sound, but my observations donÂ´t confirm this. (To me it makes sense that itÂ´s easier to loose control of your attention when you hear a "melody" in a smooth sound. I think this because IÂ´m convinced that this illusion is related to the voices I hear. Without any attention devoted to verbal tasks my brain payes more attention to a "vocal tone" sound and similar to what happens when itÂ´s a question of divided attention between verbal and vocal tone aspects of a voice this means that you loose control.)
As described the vocal tone and "vocal tone" speech sounds of my own voice was synchronized with the sound that was interpreted thanks to "attention modification" and when it comes to the alien voice vowels and other speech sounds pronounced with the vocal tone of the voice is also synchronized by being triggered when the volume of the sound makes a short change to a higher volume. To be more precise you have to include other speech sounds and the changes in volume actually triggers syllable by syllable into words and sentences. To make the synchronization of the vocal tone of an alien voice with a changing sound of low volume possible I concluded that a combination of "attention modification" (that causes a subjectively perceived change in volume) and triggering (caused by objectively perceived changes in volume) is needed to give the "melody" and emotional content of language. If you maybe exclude the illusionary perception of single words what I call "attention modification" is probably necessary if you donÂ´t interpret a distant voice that already has its own "melody". Subjectively perceived changes in volume is not possible if the volume is to high and maybe thatÂ´s one reason why the volume of the sound I interpret when I hear voices often is very low.
My own thoughts that were spoken out "loud" were only disturbed when they were perceived as alien. In the beginning almost all of these sentences were abrupted and later my brain seemed to adjust to this by thinking in shorter sentences or sometimes even single words. The explanation why some sentences were abrupted came to me by paying even more attention to the sound that was interpreted and perceived as an alien voice. The result was that I could intentionally end a sentence that without my control otherwise probably would have continued with some more words. If you do this on purpose you end up hearing the sound behind the voice which is not the case when attention is increased automatically. If the intentional effort to increase attention towards the sound that substitute the vocal tone of the inner voice doesnÂ´t manage to end the sentence I have noticed that the voice sometimes tends to repeat itself supposingly because of the shift in attention. (verbal thoughts (- but not enough to end the sentence) and the "vocal tone" sound (+) This is called "echo de la pensee" and is a very irritating symptom that appeared more commonly when I with some effort managed to think quiet thoughts.) This none intended increase in attention that supposingly lays behind the ending of the sentence was often followed by an immediate shift of attention to another more peripheral sound that gave rise to a new voice and so on. (very hard to cope when itÂ´s like that)
When the thought take the form of a new alien voice it often makes a jump and changes direction and maybe some clues to why certain disturbances in verbal thinking sometimes occur could be understood by shifts in or an increase in attention.
The Role of Corollary Discharge and Divided Attention?
My conclusion is that divided attention explains why it is only possible to interpret peripheral sounds. (low volume or in white noise and assumed to be peripheral because I donÂ´t hear a voice in a sound that substitute the vocal tone of my inner voice if IÂ´m able to devote enough attention to it. ) This conclusion could also give a possible answer to why my thoughts become alien if the awareness of the imagined formation of the words (verbal self-monitoring) included in normal verbal thinking competes with attention devoted to a peripheral "vocal tone" sound because of the limited attention span that is so obvious in divided attention tasks. (Attenuated activation when processing inner speech in areas implicated in verbal self-monitoring maybe due to increased attention to a "vocal tone"(internal or external) sound which leads to suppression of other sounds correspondent to a verified decrease in the responsiveness of primary auditory cortex during auditory hallucinations?) My experience (and common sense) also confirms that some awareness of the imagined formation of the words is necessary to control a thought and to perceive it as a result of ones own actions. Automatic processes works with less attention also when it comes to a divided attention task and maybe thatÂ´s why verbal self-monitoring fails before what I assume are more automatic processes of verbal thinking ends. (This might serve a purpose at least according to my understanding of The motor theory of speech perception if automatic verbalization of the context without self-monitoring is essential to enable an interpretation. The existence of mirror neurons support this theory and what they call alien verbal monitoring.) I actually think this is a more thorough explanation than failure of corollary discharge that attenuates the response to self produced stimuli and presumably also the attention controlled by a sensory memory (the vocal tone and all speech sounds of the inner voice) devoted to synchronized correspondent features of externally generated stimuli. (A cricket that is unable to sing due to the lack of one wing suppress certain external sounds (when it sings silently) thanks to corollary discharge and I assume that I would be able to suppress an external sound that objectively of course only substitute non verbal sounds(vocal tones) of my inner voice when I hear my thoughts out "loud" if corollary discharge didnÂ´t fail. If functional auditory hallucinations are related to speech perception itÂ´s possible to understand why corollary discharge is absent because normally you donÂ´t want to suppress external sounds correspondent to your inner voice( the sensory consequence of the motor signal synchronized with external speech) during speech perception. My understanding of speech perception is influenced by my experience and not necessary correct according to the latest version of The motor theory of speech perception.) I think this because the absence of corollary discharge only gives a possible explanation to why my thoughts are heard out "loud" and not why they are affected. To understand this I think that itÂ´s necessary to assume that the brain can't simultaneously give full attention to both verbal thinking and an external or internal sound which substitute the vocal tone of the inner voice. (According to one source corollary discharge is due to a specific attenuation mechanism and not the attentional demands of the task. This means that less attention is devoted to the sensory consequence of a task, but not related to the attentional demans of a task and thatÂ´s why they donÂ´t think that corollary discharge has anything to do with divided attention. What I assume is that my verbal thoughts are affected when corollary discharge is absent due to attentional demands and divided attention(verbal thoughts- and a "vocal tone" sound+).)
Finally I wonder if divided attention between a "vocal tone" sound (vocal(non-verbal) information that brings melody and emotion to a voice) and verbal thoughts (that reflect language abilities) correlates to changes in activity of both the left (-if dominant) and right (+) side of the brain due to competition for neuronal resources. (If so this might explain why the right hemisphere involment in the mediation of left hemisphere language functions is greater than normal. This is not limited to people who hear auditory hallucinations and maybe some people diagnosed with schizophrenia, but without alien voices, pay more attention to certain vocal "less verbal"(tone) aspects of external and internal speech than what is normal. If "my own voice" was experienced inside my head, like some experience auditory hallucinations, IÂ´m not sure that I would be able to tell the difference between these thoughts (vulnerable due to the possible occurrence of divided attention between verbal (-) and vocal tone (+) aspects) and normal thoughts. The transmigration of certain language functions from the left to the right hemisphere in schizophrenia is thought to be the cause of the right hemisphere dysfunctions. I assume that competition for neuronal resources disturbs the normal integration of vocal and verbal information and that different areas than normal on the right side take over certain verbal tasks from areas on the left that normally take care of verbal tasks of this nature. Comming from me this of course is pure speculation, but if itÂ´s true it might also affect the emotional response you experience. If covert or overt speech is hard to control and maybe sometimes a bit alien(which is the case when you give the vocal tone to much attention) the feelings attached to the verbal content might be the same as if you heard somebody else speak, but maybe the emotional response is affected in other ways due to the transmigration.)
How I Understood the Verbal Illusion with the Help of Two Tests
When I listened to a recorded sound that was played in intervals with short breaks and synchronized my thoughts by reading something syllable by syllable when the sound was heard (in a couple of minutes) I ended up hearing "my own" voice. (This is not possible now maybe because I donÂ´t hear what I perceive as my own thoughts in external sounds any more and this is also a bit strange because if you think monotonously a couple of syllables your own thoughts normally become quiet and not heard out "loud".) If I increased the volume of the sound behind my own voice in this test the illusion of hearing a voice was lost. I donÂ´t know if divided attention fully can explain this and other things because I didnÂ´t notice any of the expected changes in my verbal thoughts. (The only thing that happened was that my thoughts were more easily synchronized almost like they were triggered. The observation that the voice sometimes become less alien if you manage to accurately predict the message might be useful if you want to get some understanding of what seems to be a contradiction. If my memory of this observation is correct what you experience when you do like this is an improvement of verbal self-monitoring and with this I mean that you are more aware of that you imagine the movements needed to produce different speech sounds. Another attempt to understand why the heard voice in this test doesnÂ´t become alien when the volume increases is to assume that you only interpret peripheral sounds and then if itÂ´s a divided attention task you must have given your thoughts more attention which according to my theory would result in verbal self-monitoring. If this is correct and an alien voice is heard in a sound of high volume your total attention span devoted to interpret the sound must be temporarily impaired.) Maybe my brain simply prefers a more objective perception when the stimuli is stronger. An alien voice in a sound that comes and goes like this doesnÂ´t necessary have to end like it usually does in a sound that continues without interruptions.
The most insidious symptom that might lead to false beliefs is when verbal illusions defined as functional auditory hallucinations make you believe that you can hear distant voices when all you hear objectively is the vocal tones of these distant voices. This is why I wanted to simulate the circumstances needed to induce functional auditory hallucinations which was done with the help of a soundfile with a lot of white noise used to mask distant voices talking in the background. (An objective perception was hereby prevented, but still I could hear them talk... and in real life you only need to hear a couple of words to start and fuel false beliefs.)
So far I have mostly been talking about my understanding of interpretations of external sounds, but I wouldnÂ´t be surprised if voices without an external link could be understood by applying the same ideas like divided attention etc.
The auditory hallucinations I have come very close to auditory illusions common in speech perception. Auditory illusions arise when it is hard to hear the spoken words and fragments of none verbal sounds is necessary to enable the perceptual restoration to occur. (I wonder if a better understanding of speech perception, maybe more research about the motor theory of speech perception, might cast some light over verbal auditory hallucinations if itÂ´s possible to understand why certain differences occur.)
Many of my friends share the experience that what is considered to be auditory hallucinations sometimes include interpretations of external sounds. (The phenomenon EVP further confirms the ability of the human brain to interpret "white noise" when it expects to hear certain words) I recently found out that this is what you call functional auditory hallucinations if you are diagnosed with schizophrenia.
Why Did I Start to Hear Voices? (Pure speculation and maybe too simple. One source talk about learning, but I do not yet understand it all.)
The abilities that make speech perception possible is thought to be inherent, but this doesnÂ´t exclude the possibility that the tendency for topp-down driven activity (and more subjective perceptions like the voices I hear) may arise through learning. In speech perception they call this perceptual restoration and I assume that if this activity occurs more frequently it will result in a stronger association between non verbal sounds and the verbal content of your thoughts. During speech perception perceptual restoration occurs in a noisy environment, due to reduced hearing, but also because of other reasons like when volition and emotion make you listen to indistinct, maybe distant and hard to hear voices. Theoretically perceptual restoration might also occur if my brain, due to injury or an inherent inability, is not able to give an entirely objective perception during speech perception.
The state I was in earlier lasted a couple of years and made it possible to make very detailed observations. This it not possible any more but I still believe that most of my observations are valid. I now understand that it could be difficult to verify some of my observations, but still I hope that somebody would give it a try.
Topics related to schizophrenia issues and treatment; schizophrenia as a vestige of the bicameral mind.
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