Tag Archives: Psychology

My Biggest Pet Peeve in Consciousness Research

 

Boy was I excited to read that new Nature paper where scientists report experimentally inducing lucid dreaming in people. Pretty cool, right? But then right in the abstract I run across my biggest pet peeve whenever people use the dreaded c-word: blatant terminological inconsistency. Not just an inconsistency across different papers, or buried in a footnote, but between a title and an abstract and within the abstract itself. Consider the title of the paper:

Induction of self awareness in dreams through frontal low current stimulation of gamma activity

The term “self-awareness” makes sense here because if normal dream awareness is environmentally-decoupled 1st order awareness than lucid dreaming is a 2nd order awareness because you become meta-aware of the fact that you are first-order dream-aware. So far so good. Now consider the abstract:

 Recent findings link fronto-temporal gamma electroencephalographic (EEG) activity to conscious awareness in dreams, but a causal relationship has not yet been established. We found that current stimulation in the lower gamma band during REM sleep influences ongoing brain activity and induces self-reflective awareness in dreams. Other stimulation frequencies were not effective, suggesting that higher order consciousness is indeed related to synchronous oscillations around 25 and 40 Hz.

Gah! What a confusing mess of conflicting concepts. The title says “self-awareness” but the first sentence talks instead about “conscious awareness”. It’s an elementary mistake to confuse consciousness with self-consciousness, or at least to conflate them without making an immediate qualification of why you are violating standard practice in so doing. While there are certainly theorists out there who are skeptical about the very idea of “1st order” awareness being cleanly demaracted from “2nd order” awareness (Dan Dennett comes to mind), it goes without saying this is a highly controversial position that cannot just be assumed without begging the question. Immediate red flag.

The first sentence also references previous findings about the neural correlates of “conscious awareness” being linked to specific gamma frequencies of neural activity in fronto-temporal networks. The authors say though that correlation is not causation. The next sentence then makes us believe the study will provide that missing causal evidence about conscious awareness and gamma frequencies.

Yet the authors don’t say that. What they say instead is that they’ve found evidence that gamma frequencies are linked to “self-reflective awareness” and “higher-order consciousness”, which are again are theoretically distinct concepts than “conscious awareness” unless you are pretheoretically committed to a kind of higher-order theory of consciousness. But even that wouldn’t be quite right because on, e.g. Rosenthal’s HOT theory, a higher-order thought would give rise to first-order awareness not lucid dreaming, which is about self-awareness. On higher-order views, you would technically need a 3rd order awareness to count as lucid dreaming.

So please, if you are writing about consciousness, remember that consciousness is distinct from self-consciousness and keep your terms straight.

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A Brief History of the Vegetative State

persononlifesupport

1.0 Introduction
Vegetative state syndrome (VS) is a rare but extremely devastating neurological disorder resulting from severe brain damage. The increasing sophistication of critical neural care has made it possible for people to be kept alive with only the barest of brain function; machines can now take over the control and regulation of basic organic functions. An estimated 13,000-44,000 Americans are currently in a vegetative state. The causes of VS are diverse ranging from traumatic brain damage such as from car accidents to hypoxia from drowning, stroke, heart attack, or drug overdoses. VS is considered a disorder of consciousness insofar as it is assumed to deeply affect conscious awareness. Hence, VS is widely described as “wakefulness without awareness” or “wakeful unawareness” (Jennet & Plum, 1972).

When most laypersons hear about VS they think about so called “persistent vegetative state” which is a term used to describe VS patients 1 month after acute injury. Persistent VS is often confused with permanent VS which is defined by the Multi-Society Task Force as a VS state 3 months after a non-traumatic brain injury and 12 months after traumatic injury. VS is often confused with brain death, which is the complete and irreversible cessation of neurological function. VS is also distinct from being in a coma, a term that comes from the ancient Greek term “koma”, meaning “deep sleep” (Fig. 1). Coma is operationally defined in terms of a complete lack of overt response to vigorous stimulation and attempts to arouse the patient. Plum and Posner define the state of coma as being

unarousable, unaware of all elements in the environment, with no spontaneous interaction or awareness of the interviewer, so that the interview is difficult or impossible even with maximum prodding (2007, p. 184).

Coma patients are still breathing and their basic physiological systems are still functioning but their eyes never open and they appear to be in a deep sleep marked by a presumed total lack of consciousness. If a patient recovers from a coma at all, they typically begin to recover after a week or two, transitioning through progressive stages starting with vegetative state and ideally moving through a continuum of minimally conscious states to either locked-in syndrome, or a full cognitive recovery.

SpectrumDOC1

Fig. 1 From (Posner, 2008).

2.0 Ancient to Modern Conceptions of the Vegetative State
The concept of VS can be indirectly traced by to Ancient Greece and the Hippocratic school of medicine (400-200 BCE), sometimes called the “Coan school” because it was apparently located on the island of Cos in the Aegean Sea. Some scholars believe that the Hippocratic school was an ancient Pythagerean-like cult that had a quasi-religious and mystical set of beliefs and initiation rights. In Ancient Greek medicine one of the terms closest to referring to what is now called the vegetative is the condition called “apoplexy”, referred to stroke or brain hemorrhage, meaning “being struck by violence”. Due to the complete lack of knowledge of how brain damage affected cognitive function, the ancient Greeks lumped many more neurological conditions under the same category than we would do now. Consider the following Hippocratic description of apoplexy

The healthy subject is taken with sudden pain; he immediately loses his speech and rattles his throat. His mouth gapes and if one calls him or stirs im he only groans but understands nothing. He urinates copiously without being aware of it. If ever does not supervene, he succumbs in seven days, but if it does he usually recovers (Clarke, 1963, p. 307)

Besides the Hippocratic writings, the most comprehensive source of Ancient knowledge about apoplexy comes from the works of Galen written between 200-150 BCE.Although Galen’s writings on apoplexy were fragmented and scattered through his corpus, his writings on the subject constitute the first medical taxonomy of the condition. According to Galen, “Apoplexy [is] a palsy of the whole body, accompanied by impairment of its leading functions” (Quoted in Karenberg, 1994, p. 87).

Since Galen, little progress in diagnosing, understanding or treating apoplexy was made in between ancient Greece and the the beginning of the Enlightenment and the birth of modern, mechanistic approaches to medicine such as William Harvey’s hydraulic model of the circulatory system. Much of this lack of progress can be chalked up to the collapse of the Roman empire, the rise of the institutions of the Church and numerous other complex social, economic, and political factors. The scholastic and highly conservative nature of medicine essentially kept the Hippocratic conception of apoplexy intact all the way up through the 17th century. For example, when we read 17 century doctor Thomas Willis’ description of apoplexy, it’s quite apparent that 17th century medicine had made little progress in the description of these complex and tragic neurological conditions. According to Willis,

The Apoplexy, according to the import of the Word, denotes a striking, and by reason of the stupendous Nature of the affect, as tho it contain’d somewhat Divine, it is called a sideration: for those that are seized with it, as tho they were Planet-struck, or smitten by an invisible Deity, fall on the Ground on a sudden, and being deprived of Sense and Motion, and the whole animal function (unless that they breath) ceasing, they lye dead as it were for some time, and sometimes dye out-right: and if they revive again, they are oftentimes affected with a general Palsie or an Hemiplegia. (quoted in Storey, C.E., 2007)

For the most part all these doctors could do is either watch the patient die or rely on the spontaneous healing powers intrinsic to the brain itself. During the Middle Ages brain damage was by necessity diagnosed on the basis of easily observable features and thus the typical neurological examination was rudimentary in nature, consisting largely on the basis of: “inspection, palpation of the pulse, and urinoscopy” (Walker, 1998, p. 157).

Until the 19th and 20th centuries, only sparse and intermittent advancement was made in the diagnostic categorization of disorders of consciousness owing to neurological damage. To give some representative examples of the slow terminological evolution, in the 17th century Thomas Willis used the term “coma” in his 1672 work De anima brutorum. In 1679 in Geneva Switzerland Theophile Bonet published Sepulchretum sive Anatomia Practica, a huge compendium of autopsy reports, 70 of which were cases of apoplexy. In the 18th century the Dutch botanist and physician Herman Boerhaave’s described the term “coma” in his lectures as follows:

It is the perfect image of a very profound sleep, like in healthy persons, due to exercise or fuddle. Therefore, there is little distinction, unless by duration. (quoted in Koehler, 2008)

Also of note, in 1898 Oppenheim distinguished between dazedness, somnolence, sopor and coma, which was one of the first modern taxonomies that systematically distinguished between different “levels” of consciousness.As we can see then, between the Middle Ages and the 20th century there was not a great deal of progress made in either diagnosing or treating apoplexy and the state of the field remained largely stagnant.

3.0 Contemporary Approaches to the Vegetative State

The modern history of the vegetative state begins with advances in EMT rescue and technology for sustaining bodily viability in the absence of normal brain function. The artificial respirator was invented in the 1950s by Bjorn Ibsen, a Dutch anesthesiologist who founded the first Intensive Care Unit. Since then, medical advances in artificial nutrition and hydration (ANH) enabled vegetative patients to live decades after the onset of brain damage without higher brain brain or evidence of awareness. The longest known case of VS is Elaine Esposito who was in a VS state for thirty-seven years. Surveys show that people perceive that living decades in this condition or ones similar to it would be a fate “worse than death” (Jennett, 1976) and most people including doctors would prefer to not be kept alive. Most patients deemed not to have a life worth living have ANH withdrawn, which is thought to release endogenous opioids and eventually lead to confusion and then coma from metabolic dysfunction.

Bryan Jennett, a British neurosurgeon and Fred Plum, an American neurologist, coined the term “persistent vegetative state” in a landmark paper published in Lancet in 1972 on April Fools Day. The paper was subtitled “A syndrome in search of a name”. The subtitle “in search of a name” is a reference to the fact that many similar descriptions of vegetative state were available at the time but none of them were broad enough to capture the vegetative state as a syndrome. For example, “Neocortical necrosis” is a term that was applied to a subset of vegetative patients but all such terminology was eventually replaced by terms that didn’t imply any particular causal etiology because of the heterogeneous causes that lead to behavioral unresponsiveness.

Extant medical vocabulary circling around at the time include the French term “coma vigil” Cairns’ term “akinetic mutism” in 1941 to describe a patient with “silent immobility”, German psychiatrist Kretschmer’s term “apallic syndrome”, Stritch (1956) discussions of “severe traumatic dementia”, Arnaud’s term “pie vegetative” in 1963, and Finnish neurosurgeon Vapalahti and Troupp’s “vegetative survival” in 1971. Most of these terms were never universally adopted for the same reason: they were over-specific with respect to the neurological damage or behavioral sequelae. Hence, because Jennett and Plum’s original vegetative syndrome was operationally defined only by a lack of behavioral responsiveness rather than any specific neurological deficit, the term started to enter the general medical lexicon and eventually made it’s way (controversially) into the public sphere due to many high-profile legal cases. Accordingly, Jennett and Plum were not the first to use the phrase “vegetative” nor were they the first to notice and describe the syndrome, but the name they chose stuck and has been in use ever since (though there is now efforts to rename the syndrome; see below). Fred Plum went on to write an influential textbook in the field with Jerome Posner called Diagnosis of Stupor and Coma, which is still in use and currently in its 4th edition (Posner et al., 2008)

The usage of the word “vegetative” to describe people with severe brain damage has always been controversial amongst the general public. One possible reaction to the term is to see it as violating the dignity of the patients by comparing their mental life to that of vegetables. But in the defense of Jennett and Plum, when they first coined “vegetative state”, they referenced the Oxford English Dictionary’s definition of the verb “vegetate”, meaning “To live a merely physical life devoid of intellectual activity or social intercourse”. This usage of the term “vegetate” can be traced back to Ancient Greece e.g. Aristotle’s talked about a “vegetative soul” that was present in all living things including humans. In this respect the term “vegetative” was always meant to be a purely descriptive term for the mental capacity of the patients but it’s hard for laypersons not to read into the term some kind of pejorative connotation.

3.1 Assessment Scales

The history of diagnosing VS and related disorders of consciousness goes hand in hand with the development of behavioral assessment scales and recovery scales. One of the original assessment scales–still in use today–is the Glasgow Coma Scale (GCS) developed by Jennett and Teasdale (1974). The GCS involves 3 dimensions (eyes, verbal, and motor). The eye dimension is graded on a 4-point scale, verbal on a 5 point scale, and motor on a 6 point scale. Thus, the highest possible score is 15 indicating normal consciousness and 3 the lowest, indicating coma or brain death. On the recovery side of things, the Glasgow Outcome Scale was proposed by Jennett and Bond (1975) and describes 5 levels of brain function ranging from coma to VS to severe, moderate, and low cognitive disability. In terms of diagnosis, the JFK Coma Recovery Scale-Revised is currently the gold standard and best validated assessment protocol for diagnosing vegetative patients (Giacino et al., 2004). It involves 6 subscales including auditory, motor, verbal, and visual components. The test is designed to use only observable responses to bedside commands and tests, which allows the test to be used cheaply so long as performed in the hands of trained experts.

3.2 Minimally Conscious State

Today the diagnosis of vegetative state has become more complex and multifaceted in order to recognize the greater heterogeneity and range of cognitive abilities of people diagnosed with the blanket term “vegetative”. Recognizing the need for a more nuanced diagnosis to distinguish patients who are largely vegetative but show intermittent and non-repeatable signs of consciousness, the term “minimally responsible state” (MRS) was introduced by the American Congress of Rehabilitation in 1995. The difference between this and coma or PVS was that MRS required the observation of something “unequivocally meaningful” to the examiner. Later, a group known as the Aspen Workgroup recommended MRS be replaced by “minimally conscious state” (MCS) to emphasize that behavioral responsiveness can occur without consciousness. An estimated 100,000 to 280,000 cases of MCS are thought to exist in the US. The current consensus is that Giacino’s (2002) diagnostic criteria is the gold standard for assessing MCS. Giacino’s definition involves 4 levels of “non-reflexive” behavior:

  • Following simple commands,
  • Gestural or verbal yes/no responses (regardless of accuracy,
  • Purposeful behavior such as those that are contingent due to appropriate environmental stimuli and are not reflexive.
  • Intelligible verbalization.

Any demonstration of these abilities warrants the diagnosis of MCS instead of VS. Currently, these assessment scales like an overarching theoretical basis and without an accepted theory of consciousness it’s unclear whether consciousness is necessary for command following or purposeful behavior, especially given the many apparent counter-examples in clinical neuroscience such as blindsight (c.f. Levy, 2009).

3.3 Famous cases

The modern history of the vegetative state cannot be told without reference to the famous legal cases that were crucial in spurning interest and research on the condition from neurologists, ethicists, and the public at large. These cases operated as catalysts for more precise diagnostic criteria as well as standardization of assessment scales that can be implemented objectively by independent hospitals.

Karen Quinley

Karen Quinley’s case is famous for its association with the right-to-die movement. Karen Quinley was 21 in 1975 when she was found unconscious after an overdose of drugs and alcohol with her friends. After 5 months on a respirator Karen was still in a vegetative state and being cared for in the intensive unit. Karen’s parents, the Quinlans, requested that her respirator be removed because it was deemed by the Catholic church an “extraordinary” medical intervention and thus its removal would not constitute euthanasia, a procedure prohibited by the Catholic doctrine. However, Karen’s neurologist objected to removing the respirator, arguing this would be tantamount to killing her. Eventually the case went to the Supreme Court of New Jersey and the judges decided that the duty to protect life was overridden by the dim prognosis of future awareness. After Karen’s respirator was removed she was still on artificial nutrition and remained alive for another ten years.

Terri Schiavo

On February 25, 1990 Teresa “Terri” Schiavo (age 26) suffered a heart attack and lapsed into a coma. After two months with no signs of recovery, Schiavo was diagnosed with vegetative state disorder (VS). After several years and no signs of recovery, her husband asked to remove her feeding tube. Schiavo’s family objected, arguing that she showed intermittent signs of awareness. Subsequent legal battles involved 14 appeals and widespread media coverage but fifteen years after Schiavo’s heart attack a judge finally ordered her feeding tube to be removed and she died three days later on March 31, 2005.

When Schiavo was diagnosed, VS had not yet been widely distinguished from what is now called the minimally conscious state (MCS), a once controversial diagnosis. MCS patients are similar to VS patients but intermittently show clear signs of consciousness such as purposive behavior but these signs often cannot be reproduced. Once MCS became an established diagnosis (Giacino, 2004), Schiavo’s family later argued in court that she was in a MCS not VS and several doctors testified to this effect. Nevertheless, the judge ruled that Schiavo was in a VS state and that her condition was irreversible.

4.0 21st Century Approaches to the Vegetative State

Investigation into VS and related disorders has exploded in the 21st century. One of the biggest developments in the field came when Adrian Owen and his team published a paper in 2006 in Science claiming to have detected residual levels of consciousness in a patient clinically diagnosed with VS. This discovery sparked intense debate about the methodology and philosophical assumptions of the study but skeptics were finally answered in 2010 when Monti (2010) did a follow-up replication with 50+ subjects. In Monti’s study they found 3 patients in the vegetative state who were capable of “willful modulation” using Owen’s mental imagery paradigm. More recently, a 2014 study published in The Lancet found at least 13 cases of residual cognitive function in patients otherwise diagnosed with vegetative state disorder

4.1 Unresponsive wakefulness syndrome

Unresponsive Wakefulness Syndrome (UWS) is a new term for VS (Laureys et al., 2010; Laureys & Boly, 2012) that is more respectful of patient dignity as well as more diagnostically accurate. Although the term “vegetative” is accurate as a medical generalization across a population of patients, the problem comes when clinicians diagnose a particular person.It’s one thing to talk about vegetative patients in the abstract but if a doctor described your loved one as “vegetative” it would be hard not to find this an frightening, alien label. Despite its pretension to be a merely descriptive term, “vegetative” has negative connotations of a life not worth living, of being “vegged out”.

Furthermore, because modern neuroimaging techniques can now detect residual cognitive function that escapes bedside assessment, it is hasty to infer a patient lacks all cognitive function until they have been systematically tested using the latest technology. The term “vegetative” is inaccurate as a blanket diagnostic label because it ignores the possibility that they will find residual cognitive function using neuroimaging and other techniques that go beyond bedside behavior. The term “unresponsive” is therefore more appropriate than “unaware” and encourages clinicians to not use a single, monolithic state to describe what is in reality a complex continuum. Even though VS is a purely behavioral diagnosis and by itself strictly entails nothing about the presence or absence of consciousness, it’s hard even for clinicians to not adopt a “clinical nihilism” towards these patients despite the very real possibility of these patients having residual cognitive function that – if expressed – would change the diagnosis. However, it’s crucial to realize that there is no logical or empirical basis for inferring the absence of awareness from the absence of a behavioral response, especially since we know through retrospective report that locked-in patients who emerged from total lock-in syndrome were often thirsty, in pain, and aware of nurses and doctors talking around them but completely unable to move any muscles. We also know from retrospective reports of patients under general anesthesia that approximately 1-2 per 1000 cases report some degree of awareness during anesthesia even though they showed no overt motor response detected by the surgeons (Sebel, 2004).

There are many reasons why someone’s awareness would not be detected by a clinical test even if was actually present (Sanders et al., 2012). If we want to hold onto the idea that consciousness as subjective experience is something we share with animals, it’s not obvious why an ability to report one’s experience is necessary to having an experience in the first place. Hence, despite the careful qualifications of the original inventors of the label “vegetative state”, the term has taken on a life of its own and now probably does more harm than good by priming people to think about consciousness as being either “on” or “off” when reality is more complicated, with VS patients as a population being heterogeneous and falling along a broad spectrum of states – not one monolithic neurological or experiential state (Laureys & Boly, 2008).

4.2 Future Developments

The future of coma science will likely involve the further implementation of advanced neuroimaging technology into the standard practice of clinical diagnosis. Already research teams across the globe are racing to build the first truly validated “consciousness-o-meter” that can be used to quickly diagnosis an unresponsive patient’s level of consciousness without relying on traditional behavioral assessment scales which rely on the subjective judgment of expert raters (Casali et al., 2013). The future will also involve the development of better brain-computer interface techniques to interact with UWS patients who emerge into locked-in syndrome, such as Sorger et al.’s (2013) real-time fMRI speller method (Fig. 2). The future will also bring new developments in therapeutic intervention to help foster neural plasticity and functional recovery using stimulation techniques like transcranial direct current stimulation (tDCS) or deep brain stimulation (Schiff et al., 2007) in addition to pharmacological interventions using anti- insomnia drugs like zoldipem (Brefel-Courbon et al., 2007).

sorgerspeller

Fig. 2 From (Sorger et al., 2013).

Conclusion

The concept of vegetative state has been loosely recognized, categorized, and discussed for thousands of years but it has only really been in the last 40 years or so that the condition has been rigorously defined and studied using the modern methods of clinical science. Ironically, the more rigorously VS is studied the fuzzier its definitional boundaries become, with most researchers now conceiving of the VS “state” as just one specific band in a continuous, multidimensional spectrum of cognition function. Thus, the more we study the vegetative state the more we realize that the term itself should be abandoned and replaced with a clinically validated set of consistent terminology based on an conceptually and empirically coherent understanding of consciousness that acknowledges a spectrum of possible states a patient could be in when they are seemingly unresponsive to the proddings an external observer.

References

Brefel‐Courbon, C., Payoux, P., Ory, F., Sommet, A., Slaoui, T., Raboyeau, G., … & Cardebat, D. (2007). Clinical and imaging evidence of zolpidem effect in hypoxic encephalopathy. Annals of neurology, 62(1), 102-105.

Casali, A. G., Gosseries, O., Rosanova, M., Boly, M., Sarasso, S., Casali, K. R., … & Massimini, M. (2013). A theoretically based index of consciousness independent of sensory processing and behavior. Science translational medicine, 5(198), 198ra105-198ra105.

Clarke, E. (1963). Apoplexy in the Hippocratic writings. Bulletin of the History of Medicine, 37, 301.

Giacino, J. T., Ashwal, S., Childs, N., Cranford, R., Jennett, B., Katz, D. I., … & Zasler, N. D. (2002). The minimally conscious state definition and diagnostic criteria. Neurology, 58(3), 349-353.

Giacino, J. T., Kalmar, K., & Whyte, J. (2004). The JFK Coma Recovery Scale-Revised: measurement characteristics and diagnostic utility. Archives of physical medicine and rehabilitation, 85(12), 2020-2029.

Gosseries, O., Bruno, M. A., Chatelle, C., Vanhaudenhuyse, A., Schnakers, C., Soddu, A., & Laureys, S. (2011). Disorders of consciousness: what’s in a name?. NeuroRehabilitation, 28(1), 3-14.

Jennett, B. (1976). Resource allocation for the severely brain damaged.Archives of neurology, 33(9), 595-597.

Jennett, B., & Plum, F. (1972). Persistent vegetative state after brain damage: a syndrome in search of a name. The Lancet, 299(7753), 734-737.

Jennett, B., & Bond, M. (1975). Assessment of outcome after severe brain damage: a practical scale. The Lancet, 305(7905), 480-484.

Karenberg, A. (1994). Reconstructing a doctrine: Galen on apoplexy. Journal of the History of the Neurosciences, 3(2), 85-101.

Koehler, P. J., & Wijdicks, E. F. (2008). Historical study of coma: looking back through medical and neurological texts. Brain, 131(3), 877-889.

Laureys, S., & Boly, M. (2008). The changing spectrum of coma. Nature Clinical Practice Neurology, 4(10), 544-546

Laureys, S., Celesia, G. G., Cohadon, F., Lavrijsen, J., León-Carrión, J., Sannita, W. G., … & Dolce, G. (2010). Unresponsive wakefulness syndrome: a new name for the vegetative state or apallic syndrome. BMC medicine, 8(1), 68.

Levy, N., & Savulescu, J. (2009). Moral significance of phenomenal consciousness. Progress in brain research, 177, 361-370.

Monti, M. M., Vanhaudenhuyse, A., Coleman, M. R., Boly, M., Pickard, J. D., Tshibanda, L., … & Laureys, S. (2010). Willful modulation of brain activity in disorders of consciousness. New England Journal of Medicine, 362(7), 579-589.

Owen, A. M., Coleman, M. R., Boly, M., Davis, M. H., Laureys, S., & Pickard, J. D. (2006). Detecting awareness in the vegetative state. Science, 313(5792), 1402-1402.

Posner, J., Plum, F., Saper, C., Schiff, N., &.(2007). Plum and Posner’s Diagnosis of Stupor and Coma. Oxford, UK: Oxford University Press.

Sanders, R. D., Tononi, G., Laureys, S., & Sleigh, J. (2012). Unresponsiveness≠ unconsciousness. Anesthesiology, 116(4), 946.

Schiff, N. D., Giacino, J. T., Kalmar, K., Victor, J. D., Baker, K., Gerber, M., … & Rezai, A. R. (2007). Behavioural improvements with thalamic stimulation after severe traumatic brain injury. Nature, 448(7153), 600-603.

Sebel, P. S., Bowdle, T. A., Ghoneim, M. M., Rampil, I. J., Padilla, R. E., Gan, T. J., & Domino, K. B. (2004). The incidence of awareness during anesthesia: a multicenter United States study. Anesthesia & Analgesia, 99(3), 833-839.

Sorger, B., Reithler, J., Dahmen, B., & Goebel, R. (2012). A real-time fMRI-based spelling device immediately enabling robust motor-independent communication. Current Biology, 22(14), 1333-1338.

Stender, J., Gosseries, O., Bruno, M. A., Charland-Verville, V., Vanhaudenhuyse, A., Demertzi, A., … & Laureys, S. (2014). Diagnostic precision of PET imaging and functional MRI in disorders of consciousness: a clinical validation study. The Lancet.

Storey, C. E. (2007). Apoplexy: Changing Concepts in the Eighteenth Century. In Brain, Mind and Medicine: Essays in Eighteenth-Century Neuroscience (pp. 233-243). Springer US.

Teasdale, G., & Jennett, B. (1974). Assessment of coma and impaired consciousness: a practical scale. The Lancet, 304(7872), 81-84.

Walker, A. E. (1998). The Genesis of Neuroscience. The American Association of Neurological Surgeons

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What It’s Like to Be Locked-In

Jean-Dominique-Bauby

I need to feel strongly, to love and to admire, just as desperately as I need to breathe. A letter from a friend, a Balthus painting on a postcard, a page of Saint-Simon, give meaning to the passing hours. But to keep my mind sharp, to avoid descending into resigned indifference, I maintain a level of resentment and anger, neither too much nor too little, just as a pressure cooker has a safety valve to keep it from exploding.

-Jean-Dominique Bauby, The Diving Bell and the Butterfly, p. 52

As I mentioned in this post my latest research project involves the measurement of consciousness in patients with brain damage, including the rare case of Locked-in Syndrome. I recently finished reading Bauby’s memoir about being in the locked-in state, The Diving Bell and the Butterfly where Bauby takes you inside what he called his “diving bell”, submerged in the depths of his useless body peering out at the world through the tiny window of his left eye. The memoir is nothing less than riveting, a powerful demonstration of the indefatigable human will.

Bauby dictated the entire book to an assistant with only the use of his left eye. The assistant would read off letters in the alphabet in a pre-established series arranged by frequency in the French language and Bauby would blink when the assistant spoke the correct letter; then they would start from the beginning for the next letter, and so on. You can imagine how laborious this would be. Yet the book reads beautifully, revealing an active, curious, intelligent mind trapped inside a bodily shell.

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Latest Draft of Mental Time Travel Paper

CLICK HERE to read the latest draft of “Measuring Mental Time Travel in Animals”.

I’ve been working on this paper over the semester, responding to comments and generally cleaning it up. I’ve also added a new sub-section that explores an analogy with–believe it or not–whether Pluto is a planet. I also cut down on some repetitiveness towards the end. I will be turning it in as a Qualifying Paper very soon, so any last minute comments/suggestions/corrections would be greatly appreciated.

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New paper – Measuring Mental Time Travel in Animals

For pdf click here: Williams – Measuring Mental Time Travel In Animals

Hasok Chang describes in Inventing Temperature how scientists dealt with the problem of measurement verification circularity when standardizing the first thermometers ever constructed. The problem can be illustrated by imagining you are the first scientist who wanted to measure the temperature of boiling water. What materials should you use to construct the measuring instrument? Once built, how do you verify your thermometer is measuring what you claim it is without circularly relying on your thermometer? Appealing to more experimentation is unhelpful because we must use a thermometer to carry out these experiments, and thermometers are what we are trying to determine the reliability of in the first place. Hasok Chang calls this the Problem of Nomic Measurement (PNM), which is defined as:

The problem of circularity in attempting to justify a measurement method that relies on an empirical law that connects the quantity to be measured with another quantity that is (more) directly observable.1 The verification of the law would require the knowledge of various values of the quantity to be measured, which one cannot reliably obtain without confidence in the method of measurement.

Stated more precisely, the PNM goes as follows:

1. We want to measure unknown quantity X.

2. Quantity X is not directly observable, so we infer it from another quantity Y, which is directly observable.

3. For this inference we need a law that expresses X as a function of Y, as follows:X = f(Y).

4. The form of this function f cannot be discovered or tested empirically because that would involve knowing the values of both Y and X, and X is the unknown variable that we are trying to measure.

My aim for this paper is to apply the PNM to an on-going debate in cross-comparative psychology about whether and to what extent non-human animals can “mentally time travel”. In 1997, Suddendorf and Corballis argued “the human ability to travel mentally in time constitutes a discontinuity between ourselves and other animals”.2 In 2002, Roberts argued non-human animals are “stuck-in-time”. Since then, a number of psychologists have defended similar claims. Endel Tulving states this hypothesis clearly:

There is no evidence that any nonhuman animals—including what we might call higher animals—ever think about what we could call subjective time…they do not seem to have the same kind of ability humans do to travel back in time in their own minds, probably because they do not need to. (Tulving, 2002, p. 2)

Call the claim that mental time travel is unique to humans Uniqueness. Naturally, Uniqueness has not gone unchallenged. One worry is that different theoretical assumptions about what counts as “mental time travel” are leading to disagreements over whether animals do or do not possess MTT. Furthermore, both sides of the debate more or less agree about the behavioral evidence, but disagree about how to interpret the evidence qua evidence for or against Uniqueness. This raises a problem of verification circularity similar to the PNM:

1. We want to measure MTT in animals

2. MTT is not directly observable, so we infer it from behavior Y, which is directly observable.

3. For this to work, we need to know how to infer MTT from behavior alone.

4. The form of this function cannot be discovered or tested empirically because that would involve knowing the unknown variable we are trying to measure (MTT).

Accordingly, my central thesis is that the question of whether animals can mentally time travel is not a purely empirical question. My argument hinges on premise (3): if psychologists have irreconcilable differences in opinion about which behaviors best express MTT, they will use the construct “mental time travel” to describe distinct phenomena and thus make different inferences from behavior to MTT. For example, if defenders of Uniqueness are using MTT as a label to describe a human autapomorphy3 but critics of Uniqueness are using MTT as a label for a core capacity shared with other animals, then they are clearly talking past each other and the debate is reduced to a semantic dispute about whether the term “MTT” is applied to “core” capacities or uniquely human traits.4 Therefore, I argue the empirical question of whether animals can in fact mentally time travel is intractable unless theorists can agree on both the connotative and denotative definitions of the term i.e. approximate agreement on the conceptual definition as well as agreement on its conditions of realization in the physical, measurable world.

1Chang does not analytically define the notion of “direct observation” but the paradigm case is observing the read-out of an instrument e.g. writing down the height of a column of mercury in a glass tube. Chang defends a hybrid version of foundationalism and coherentism whereby we begin scientific inquiry with some tentatively held beliefs justified by experience, especially the belief that we are capable of accurately observing the read-outs of our instruments.

2Citing neurological overlaps between “episodic-like” memory in non-human animals and human episodic memory, Corballis has recently dissented (2012). In his (2011) book, Corballis argues that what makes humans unique is our capacity for MTT and symbolic language super-charged by the capacity for recursivity i.e. Alice believes Bob desires that Chris thinks highly of Bob’s desire for Alice. Another recent convert is Roberts (2007), taking back his (2002) claims about MTT in animals.

3An autapomorphy is a derived trait that is unique to a terminal branch of a clade and not shared by other any members of the clade, including their closest relatives with whom they share a common ancestor.

4“We caution against grounding the concept of episodic-like memory in the phenomenology of the modern mind, rather than in terms of core cognitive capacities.” (Clayton et al 2003, p. 437)

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Book Report 2013 – What I’ve Read This Year

The following is a list of all the books I’ve read from front to cover in 2013, starting from the most recently finished. The books in bold are ones that were most influential to my thinking, or particularly fascinating.

  1. The Gap: The Science of What Separates Us from Other Animals – Thomas Suddendorf
  2. The Hunger Games – Suzanne Collins
  3. A Manual for Creating Atheists –  Boghossian, Peter 
  4. Simulation and Similarity: Using Models to Understand the World – Weisberg, Michael
  5. The Panda’s Thumb: More Reflections in Natural History – Gould, Stephen Jay
  6. Brain Imaging: What It Can (and Cannot) Tell Us about Consciousness – Shulman, R G
  7. Consciousness and the Social Brain – Graziano, Michael S A
  8. Wired for God?: The Biology of Spiritual Experience – Foster, Charles
  9. Genius: The Life and Science of Richard Feynman – Gleick, James
  10. The Unpredictable Species – Lieberman, Philip
  11. The God Argument: The Case against Religion and for Humanism – Grayling, A.C.
  12. Stumbling on Happiness – Gilbert, Daniel
  13. The Geography of Thought: How Asians and Westerners Think Differently… and Why – Nisbett, Richard E.
  14. Civilization and Its Discontents – Freud, Sigmund
  15. The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature – Miller, Geoffrey
  16. Radicalizing Enactivism: Basic Minds Without Content – Hutto, Daniel D.
  17. Willpower: Rediscovering the Greatest Human Strength – Baumeister, Roy F.
  18. Beyond Good and Evil – Nietzsche, Friedrich
  19. Marriage Confidential: The Post-Romantic Age of Workhorse Wives, Royal Children, Undersexed Spouses, and Rebel Couples Who Are Rewriting the Rules – Haag, Pamela
  20. Surfaces and Essences: Analogy as the Fuel and Fire of Thinking – Hofstadter, Douglas R.
  21. The Upside of Irrationality: The Unexpected Benefits of Defying Logic at Work and at Home – Ariely, Dan
  22. The Future of an Illusion – Freud, Sigmund
  23. Fooled by Randomness: The Hidden Role of Chance in Life and in the Markets – Taleb, Nassim Nicholas 
  24. How to Create a Mind: The Secret of Human Thought Revealed – Kurzweil, Ray
  25. On the Genealogy of Morality: A Polemic – Nietzsche, Friedrich
  26. The Mind-Body Problem – Goldstein, Rebecca Newberger
  27. The Marvelous Learning Animal: What Makes Human Behavior Unique – Staats, Arthur W.
  28. Sync: The Emerging Science of Spontaneous Order – Strogatz, Steven H.
  29. The Cultural Animal: Human Nature, Meaning, and Social Life – Baumeister, Roy F.
  30. Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False – Nagel, Thomas
  31. The Social Construction of What? – Hacking, Ian
  32. 36 Arguments for the Existence of God: A Work of Fiction – Goldstein, Rebecca Newberger
  33. Stiff: The Curious Lives of Human Cadavers – Roach, Mary
  34. Monkey Mind: A Memoir of Anxiety – Smith, Daniel B.
  35. The Minds of the Bible: Speculations on the Cultural Evolution of Human Consciousness – Cohn, James
  36. Brain on Fire: My Month of Madness – Cahalan, Susannah
  37. What a Plant Knows: A Field Guide to the Senses – Chamovitz, Daniel
  38. Reconstruction in Philosophy – Dewey, John
  39. Against All Gods: Six Polemics on Religion and an Essay on Kindness – Grayling, A.C.
  40. The Logic Of Modern Physics – Bridgman, Percy W.
  41. The End of Christianity – Loftus, John W.
  42. Inventing Temperature: Measurement and Scientific Progress – Chang, Hasok
  43. The New Executive Brain: Frontal Lobes in a Complex World – Goldberg, Elkhonon
  44. Thomas Jefferson: Author of America – Hitchens, Christopher
  45. Born Believers: The Science of Children’s Religious Belief – Barrett, Justin L.
  46. Brains: How They Seem to Work – Purves, Dale
  47. A Man Without Words – Schaller, Susan
  48. Beyond Morality – Garner, Richard
  49. Hallucinations – Sacks, Oliver
  50. The Signal and the Noise: Why So Many Predictions Fail – But Some Don’t – Silver, Nate
  51. Antifragile: Things That Gain from Disorder – Taleb, Nassim Nicholas 
  52. The Information: A History, A Theory, A Flood – Gleick, James
  53. Ubik – Dick, Philip K.
  54. The Art Instinct: Beauty, Pleasure, and Human Evolution – Dutton, Denis

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Quote for the Day – The Overwhelming Automaticity of Being

“Habit is thus a second nature, or rather, as the Duke of Wellington said, it is ‘ten times nature,’–at any rate as regards its importance in adult life; for the acquired habits of our training have by that time inhibited or strangled most of the natural impulsive tendencies which were originally there. Ninety-nine hundredths or, possibly, nine hundred and ninety-nine thousandths of our activity is purely automatic and habitual, from our rising in the morning to our lying down each night. Our dressing and undressing, our eating and drinking, our greetings and partings, our hat-raisings and giving way for ladies to precede, nay, even most of the forms of our common speech, are things of a type so fixed by repetition as almost to be classed as reflex actions. To each sort of impression we have an automatic, ready-made response. My very words to you now are an example of what I mean; for having already lectured upon habit and printed a chapter about it in a book, and read the latter when in print, I find my tongue inevitably falling into its old phrases and repeating almost literally what I said before.”

~William James, Talks to Teachers on Psychology: and to Students on Some of Life’s Ideals

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