Is pain where you feel it in the body, or in the brain? Neurophenomenology and the spatial aspect of nociception

Pain is interesting, salient, mysterious. It may feel like it is in one specific place in or on the body. It may feel diffuse, with gradations, or it may seem referred from one area to another. What is happening in the brain and in the body as these spatial aspects of pain are experienced? How much of the causation of pain occurs where we feel it, and how much occurs in the brain? Below is a series of probes and thinking aloud about where pain is, with speculations to stimulate my thinking and yours.  I’m not a “pain expert”, nor a bodyworker that heals clients, nor a physiologist with a specialization in nociception, but a cognitive scientist, with clinical psychology training, interested in body phenomenology and the brain.  Please do post this essay to Facebook, share it, critique, respond, and comment (and it would be helpful to know if your background is in philosophy, neuroscience, bodywork, psychology, medicine, a student wanting to enter one of these or another field, etc). Pain should be looked at from multiple angles, with theoretical problems emphasized alongside clinical praxis, and with reductionistic accounts from neurophysiology juxtaposed against descriptions of the embodied phenomenology and existential structures.  As I have mentioned elsewhere, it is still early in the history of neurophenomenology…let a thousand flowers bloom when looking at pain. We need data, observations, insights and theories from both the experience side as well as the brain side. Francisco Varela aptly described how phenomenology and cognitive neuroscience should relate:

“The key point here is that by emphasizing a codetermination of both accounts one can explore the bridges, challenges, insights, and contradications between them. Both domains of phenomena have equal status in demanding full attention and respect for their specificity.”

We all know what pain is phenomenologically, what it feels like, but how to define it? The International Association for the Study of Pain offers this definition: “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.” Of particular interest to neurophenomenology and embodied cognitive science is their claim that “activity induced in the nociceptors and nociceptive pathways by a noxious stimulus is not pain, which is always a psychological state.” Good that they do not try to reduce the experience of pain to the strictly physiological dimension, but I wonder how Merleau-Ponty, with his non-dualistic ontology of the flesh would have responded. Pain seems to transgress the border of mind and body categories, does it not? I am slowly biting off chucks of the work on pain at the Stanford Encyclopedia of Philosophy. Lots of provocative angles, including this one:

“there appear to be reasons both for thinking that pains (along with other similar bodily sensations) are physical objects or conditions that we perceive in body parts, and for thinking that they are not. This paradox is one of the main reasons why philosophers are especially interested in pain.”

Right now I am particularly interested in the spatial aspect of where pain seems to be, what I might label the spatial phenomenology of nociception. When I introspect on aching parts of my feet, it seems as if the pain occupies a volume of space. Using manual pressure I can find places on my feel that are not sore, right next to areas that are slightly sore, which are in turn near focal areas of highest pain. It seems as if the pain is locatable “down there” in my body, and yet what we know about the nociceptive neural networks suggests the phenomenology is produced by complex interactions between flesh, nearby peripheral nerves, the central nervous system, and neurodynamics in the latter especially. A way of probing this this would be to examine the idea that the pain experience is the experiential correlate of bodily harm, a sort of map relating sensations to a corresponding nerve activated by damage to tissue. So, is the place in my body where I feel pain just the same as where the damage or strain is? Or, Is pain caused by pain-receptive nerves registering what is happening around them, via hormonal and electrical signals? Or is pain actually the nerve itself being “trapped” or damaged, yet in a volume of undamaged tissue one can feel hurts? Could the seeming volume of experienced pain-space be a partial illusion, produced by cognizing the tissue damage as some place near or overlapping with yet not spatially identical to where the “actual” damage is, in other words a case of existential-physiological discrepancy? One scenario could be, roughly, that pain “is” or “is made of” nerves getting signals about damage to tissue; another would be that pain “is” the nerves themselves being damaged or sustaining stress or injury. Maybe pain involves both? Maybe some pain is one, or the other? In terms of remembering how my heel pain started, it’s not so easy, but I love to walk an hour or two a day, and have done so for many years. I recall more than ten years ago playing football in the park, wearing what must have been the wrong sort of shoes, and upon waking the next day, having pretty serious pain in my heel. Here are some graphics that, intuitively, seem to map on to the areas where I perceive the pain to be most focal:

from bestfootdoc.com

from setup.tristatehand.com

from plantar-fasciitis-elrofeet.com

If I palpate my heel, I become aware of a phenomenologically complex, rich blend of pleasure and pain. I crave the sensation of pressure there, but it can be an endurance test when it happens. Does the sensation of pressure that I want reflect some body knowledge, some intuitive sense of what intervention will help my body heal? How could this be verified or falsified? It is not easy to describe the raw qualia of pain, actually. I can describe it as achey and moderately distressing when I walk around, and sharp upon palpating. Direct and forceful pressure on the heel area will make me wince, catch my breath, want to gasp or make sounds of pain/pleasure, and in general puts me in a state of heightened activation. But I love it when I can get a therapist to squeeze on it, producing what I call “pain-pleasure”:

from indyheelpaincenter.com

This diagram below helps me map the sensations to the neuroanatomy. We need to do more of this sort of thing. This kind of representation seems to me a new area for clinical neurophenomenological research (indeed, clinical neurophenomenology in general needs much more work, searching for those terms just leads back to my site, but see the Case History section in Sean Gallagher’s How the Body Shapes the Mind).

from reconstructivefootcaredoc.com

What is producing the pain-qualia, the particular feeling? Without going too far into varying differential diagnosis, it is commonly attributed to plantar fasciitis.  There the pain would be due to nociceptive nerve fibers activated by damage to the tough, fibrous fascia that attach to the calcaneus (heel bone) being strained, or sustaining small ripped areas, and/or local nerves being compressed or trapped. A 2012 article in Lower Extremity Review states that “evidence suggests plantar fasciitis is a noninflammatory degenerative condition in the plantar fascia caused by repetitive microtears at the medial tubercle of the calcaneus.” There are quite a few opinions out there about the role of bony calcium buildups, strain from leg muscles, specific trapped nerves and so forth, and it would be interesting to find out how different aspects of reported pain qualia map on to these. Below you can see the sheetlike fascia fiber, the posterior tibial nerve, and it’s branches that enable local sensations:

from aafp.org

Next: fascia and the innervation of the heel, from below:

from mollyjudge.com

Another view of the heel and innervation:

from mollyjudge.com

Below is a representation of the fascia under the skin:

from drwolgin.com

There is a very graphic,under the skin, maybe not SFW surgeon’s-eye perspective on these structures available here. Heel pain turns out to be very common, and is evidently one of the most frequently reported medical issues. Searching online for heel pain mapping brings up a representation purportedly of 2666 patients describing where they feel heel pain: I can’t find where this comes from originally and can’t speak to the methodology, rigor, or quality of the study, but the supposed data are interesting, as is the implicit idea of spatial qualia mapping:  the correspondence of experienced pain to a volume of space in the body. It also quite well represents where the pain is that I feel. The focal area seems to be where the fascia fibers attach to the calcaneus, an area that bears alot of weight, does alot of work, and is prone to overuse. So, where is the pain? Is it in the heel or the brain? Is it in the tissue, the nerve, or both? Is there a volume of flesh that contains the pain? I am going to have to think about these more, and welcome your input. What about the central nervous system that processes nociceptive afferents coming from the body? A good model of pain neurophenomenology should involve a number of cortical and subcortical areas that comprise the nociceptive neural network: -primary somatosensory cortex (S1) and secondary somatosensory cortex (S2): -insula -anterior cingulate cortex (ACC) -prefrontal cortex (PFC) -thalamus Here are some representations of the pain pathways, or the nociceptive neural network:

from Moisset and Bouhassira (2007)

Moisett el (2009)

 

from Tracey and Mantyh (2012)

Broadly speaking, pain seems to be generated by tissue damage, inflammation, compromising the integrity of tissue, stress on localized regions, and so forth being processed by peripheral afferent pain pathways in the body, then phylogenetically ancient subcortical structures, and then the aforementioned cortical regions or nociceptive neural network.  As I have mentioned many times, making a robust account of how various regions of the brain communicate such that a person experiences qualia or sensory phenomenology will need to reference neurodynamics, which integrates ideas from the physics of self-organization, complexity, chaos and non-linear dynamics into biology.  It is gradually becoming apparent to many if not most workers in the cognitive neurosciences that there are a host of mechanisms regions of the brain use to send signals, and many of these are as time dependent as space dependent. Michael Cohen puts it thusly: “The way we as cognitive neuroscientists typically link dynamics of the brain to dynamics of behavior is by correlating increases or decreases of some measure of brain activity with the cognitive or emotional state we hope the subject is experiencing at the time. The primary dependent measure in the majority of these studies is whether the average amount of activity – measured through spiking, event-related-potential or -field component amplitude, blood flow response, light scatter, etc. – in a region of the brain goes up or down. In this approach, the aim is to reduce this complex and enigmatic neural information processing system to two dimensions: Space and activation (up/down). The implicit assumption is that cognitive processes can be localized to specific regions of the brain, can be measured by an increase in average activity levels, and in different experimental conditions, either operate or do not. It is naïve to think that these two dimensions are sufficient for characterizing neurocognitive function. The range and flexibility of cognitive, emotional, perceptual, and other mental processes is huge, and the scale of typical functional localization claims – on the order of several cubic centimeters – is large compared to the number of cells with unique physiological, neurochemical, morphological, and connectional properties contained in each MRI voxel. Further, there are no one-to-one mappings between cognitive processes and brain regions: Different cognitive processes can activate the same brain region, and activation of several brain regions can be associated with single cognitive processes. In the analogy of Plato’s cave, our current approach to understanding the biological foundations of cognition is like looking at shadows cast on a region of the wall of the cave without observing how they change dynamically over time.” But what of the original question? Is pain where you feel it in the body, or in the brain? It seems to me the answer must be both.  The experience of pain being localized there or a little on the left is a product of local tissue signals and receptor activation, which produces peripheral afferent nerve firing, which gets processed by spinal afferent neurodynamics, brainstem activation, thalamic gating, and then somatosensory, insular, anterior cingulated, and prefrontal cortical regions. Yet the real model of pain, one that invokes mechanisms and causes, remains elusive. And a good model of pain must account for the possibility of pain without suffering as well! For now, what I can offer are probes to get us speculating, thinking critically, and eventually building a clinical neurophenomenology of pain. If that interests you, by all means get involved.

An excerpt from the foundational text of neurophenomenology: Varela, Thompson, and Rosch’s The Embodied Mind

It is very,very gratifying to see interest in neurophenomenology increasing. Welcome! Exciting things are happening. If you feel like you could make a contribution to the field, do it! We are still in the early phase, though probably at the “end of the beginning”. In 1996 you could find about three references online (in mid 2013, Google shows 35,400 results). Around then I got a copy of neurophenomenologist/cognitive scientist Francisco Varela, philosopher Evan Thompson, and cognitive psychologist Eleanor Rosch’s The Embodied Mind: Cognitive Science and Human Experience. To this day I am struck by the lucidity of the writing, the patient willingness to explore the virtues of opposing viewpoints, and especially the depth of the challenge to mainstream cognitive neuroscience and psychology. The basic idea is that the science of cognition and the brain needs to somehow reckon with human experience, in all it’s phenomenological, fleshy, ecologically situated complexity. The science of human cognition requires an account of how life seems to us, how it feels, what it means. Not doing so amounts to a shortcut, though an understandable one, given the difficulties routinely encountered. The authors painstakingly present the case for why failing to include the role of the evolutionarily developed phenomenological body and the meaningful, experiential, existential dimensions will hamper scientific accounts of cognition and the brain. Varela, Thompson and Rosch present a radical challenge to the idea that the mind is best modeled based on data and measurements only from the outside, or purely objectively. Cognitive neuroscience describes cognition and consciousness as machinery emerging from the hardware of the brain, and Varela, Thompson and Rosch carefully explore the benefits of this view, but opt for a radical alternative. I am convinced it is the foundational and definitive work in neurophenomenology. Interestingly, Daniel Dennett, a staunch defender of cognitivist orthodoxy, had substantive criticism but went on to say: “the authors find many new ways of putting together old points that we knew were true but didn’t know what to do with, and that in itself is a major contribution to our understanding of cognitive science.” The term “neurophenomenology” does not appear in this book. As I have mentioned elsewhere, the term emerges around 1990 from the work of Charles Laughlin (though there seems to be one mention in a hard-to-find publication from 1988). I had considered directly contacting Varela around 1996 to convince him of the helpfulness of the term “neurophenomenology”, and I must admit to an utter dopamine blast of pleasure when around that time I found his 1996 paper “Neurophenomenology : A Methodological Remedy for the Hard Problem“. Kismet! It was an exciting time, and helped push me towards doing a PhD on one narrow aspect of clinical neurophenomenology: modeling how accurate patients are at reporting on their cardiac rhythm states, and how the brain both enables knowledge and mistaken beliefs about heartbeats . With new people showing an interest in and perhaps coming into this field, we might as well make sure to examine the core text: The Embodied Mind. There is a copy online and here is an excerpt, but I highly recommend getting a physical copy. Here is a section entitled The Retreat into Natural Selection, from Chapter 8: Enaction: Embodied Cognition (for what it’s worth, in my last class as a PhD student, I had my colleagues in David Buss‘ Evolutionary Psychology seminar read and discuss this chapter, and they hated it!) . “In preparation for the next chapter, we now wish to take note of a prevalent view within cognitive science, one which constitutes a challenge to the view of cognition that we have presented so far. Consider, then, the following response to our discussion: “I am willing to grant that you have shown that cognition is not simply a matter of representation but depends on our embodied capacities for action. I am also willing to grant that both our perception and categorization of, say, color, are inseparable from our perceptually guided activity and that they are enacted by our history of structural coupling. Nevertheless, this history is not the result of just any pattern of coupling; it is largely the result of biological evolution and its mechanism of natural selection. Therefore our perception and cognition have survival value, and so they must provide us with some more or less optimal fit to the world. Thus, to use color once more as an example, it is this optimal fit between us and the world that explains why we see the colors we do.” We do not mean to attribute this view to any particular theory within cognitive science. On the contrary, this view can be found virtually anywhere within the field: in vision research, it is common both to the computational theory of Marr and Poggio and to the “direct theory” of J. J. Gibson and his followers.  It is prevalent in virtually every aspect of the philosophical project of “naturalized epistemology.”  It is even voiced by those who insist on an embodied and experientialist approach to cognition. For this reason, this view can be said to constitute the “received view” within cognitive science of the evolutionary basis for cognition. We cannot ignore, then, this retreat into natural selection. Let us begin, once again, with our now familiar case study of color. The cooperative neuronal operations underlying our perception of color have resulted from the long biological evolution of the primate group. As we have seen, these operations partly determine the basic color categories that are common to all humans. The prevalence of these categories might lead us to suppose that they are optimal in some evolutionary sense, even though they do not reflect some pregiven world. This conclusion, however, would be considerably unwarranted. We can safely conclude that since our biological lineage has continued, our color categories are viable or effective. Other species, however, have evolved different perceived worlds of color on the basis of different cooperative neuronal operations. Indeed, it is fair to say that the neuronal processes underlying human color perception are rather peculiar to the primate group. Most vertebrates (fishes, amphibians, and birds) have quite different and intricate color vision mechanisms. Insects have evolved radically different constitutions associated with their compound eyes. One of the most interesting ways to pursue this comparative investigation is through a comparison of the dimensionalities of color vision. Our color vision is trichromatic: as we have seen, our visual system comprises three types of photoreceptors cross-connected to three color channels. Therefore, three dimensions are needed to represent our color vision, that is, the kinds of color distinctions that we can make. Trichromacy is certainly not unique to humans; indeed, it would appear that virtually every animal class contains some species with trichromatic vision. More interesting, however, is that some animals are dichromats, others are tetrachromats, and some may even be pentachromats. (Dichromats include squirrels, rabbits, tree shrews, some fishes, possibly cats, and some New World monkeys; tetrachromats include fishes that live close to the surface of the water like goldfish, and diurnal birds like the pigeon and the duck; diurnal birds may even be pentachromats).  Whereas two dimensions are needed to represent dichromatic vision, four are needed for tetrachromatic vision (see figure 8.6), and five for pentachromatic vision. Particularly interesting are tetrachromatic (perhaps pentachromatic) birds, for their underlying neuronal operations appear to differ dramatically from ours.

 

Figure 8.6 Tetrachromatic vs. trichomatic mechanisms are illustrated here on the basis of the different retinal pigments present in various animals. From Neumeyer, Das Farbensehen des Goldfisches. When people hear of this evidence for tetrachromacy, they respond by asking, ”What are the other colors that these animals see?” This question is understandable but naive if it is taken to suggest that tetrachromats are simply better at seeing the colors we see. It must be remembered, though, that a four-dimensional color space is fundamentally different from a three-dimensional one: strictly speaking, the two color spaces are incommensurable, for there is no way to map the kinds of distinctions available in four dimensions into the kinds of distinctions available in three dimensions without remainder. We can, of course, obtain some analogical insights into what such higher dimensional color spaces might be like. We could imagine, for example, that our color space contains an additional temporal dimension. In this analogy, colors would flicker to different degrees in proportion to the fourth dimension. Thus to use the term pink, for example, as a designator in such a four-dimensional color space would be insufficient to pick out a single color: one would have to say rapid-pink, etc. If it turns out that the color space of diurnal birds is pentachromatic (which is indeed possible), then we are simply at a loss to envision what their color experience could be like. It should now be apparent, then, that the vastly different histories of structural coupling for birds, fishes, insects, and primates have enacted or brought forth different perceived worlds of color. Therefore, our perceived world of color should not be considered to be the optimal “solution” to some evolutionarily posed “problem.” Our perceived world of color is, rather, a result of one possible and viable phylogenic pathway among many others realized in the evolutionary history of living beings. Again, the response on the behalf of the “received view” of evolution in cognitive science will be, “Very well, let us grant that color as an attribute of our perceived world cannot be explained simply by invoking some optimal fit, since there is such a rich diversity of perceived worlds of color. Thus the diverse neuronal mechanisms underlying color perception are not different solutions to the same evolutionarily posed problem. But all that follows is that our analysis must be made more precise. These various perceived worlds of color reflect various forms of adaptation to diverse ecological niches. Each animal group optimally exploits different regularities of the world. It is still a matter of optimal fit with the world; it is just that each animal group has its own optimal fit.” This response is a still more refined form of the evolutionary argument. Although optimizations are considered to differ according to the species in question, the view remains that perceptual and cognitive tasks involve some form of optimal adaptation to the world. This view represents a sophisticated neorealism, which has the notion of optimization as its central explanatory tool. We cannot proceed further, then, without examining more closely this idea in the context of evolutionary explanations. We cannot attempt to summarize the state of the art of evolutionary biology today, but we do need to explore some of its classical foundations and their modern alternatives.

questions about information-processing theories of body-knowledge

Cognitive science explains mind and brain in terms of computation, information-processing, and representationalism: the ability of a cognitive system to change internal microstructure so as to correspond with important features of the internal or external world. One could do worse than to sum up the cognitivist model of the mind as “computations over representations”, in which features of the world or body are coded by the brain as symbols.

Whatever merits this “cognitivist” research program may have for models of syntactical production, the consolidation of short-term memories into long-term, the recognition of familiar faces, logical problem-solving, and other phenomena, I suspect that critical aspects of how people have knowledge of their bodies are not adequately accounted for by cognitivist approaches. I maintain that a careful analysis of the evidence reveals cognitive science has a flawed approach to modeling how well people know what is happening inside their bodies, and what mental and biological processes underlay this knowledge.

There are many aspects of psychological life that have never been the focus of cognitive science, and this absence is at it’s foundation the Cartesian rift at the heart of objective models that depict mind as machine. People experience a world of meaning framed by temporality and grounded in the lived body, but cognitive science focuses on a subpersonal realm of symbols, algorithms, information processing, representation, where mind is reduced to computation. To the extent that this approach yields results, it should be pursued, but cognition outstrips what cognitivism can model. There are aspects of cognition that are characterized by the existential questions, embodied experience, consciousness, meaning, and other phenomena, but it is precisely these that objectivistic, Cartesian cognitive science has not, for the most part, tried to explain. The difference is that of between worlds, like the gap between music grasped as experienced and meaningful, compared to music understood as a system that can be analyzed through abstract system-centered objectivistic modeling. It is true that science is typically understood in the latter terms, but neurophenomenology aims at a dialog between psychological life as experienced and cognition understood as a mechanism produced by te brain. There is not an immediate move toward reduction nor a premature assumption that embodied experience can be automatically modeled as a byproduct of systems.

In everyday life, and especially in conditions of sickness or disease, people notice aspects, qualities, and states of their bodies, and seek to get information about and from their bodies. Getting information about body-state can involve perception of a symptom, focused attention or introspection toward specific body regions or parts, remembering the way one’s body felt previously and comparing this to a current assessment, attempting to verbally express feelings about the way one’s body seems, paying close attention to a body part that is usually indistinct or in the background but suddenly is painful, and many other similar activities. Consider the following examples:

• a subject in a clinical trial of a medical device is asked whether or not they notice anything unusual or different about the way their body feels, and if so, to rate how much on a numeric scale;

• a person taking psychiatric medication for depression tells their psychiatrist about adverse side effects, such as a decline in libido, and an inability to grieve the loss of a loved one while at a funeral;

• someone who is drinking alcohol may calibrate their intake based on the memory of nausea from previous episodes of over-consumption;

• an obese woman is reported by American media to have been shocked upon finding she was in labor and on the verge of giving birth, having no previous knowledge of her pregnancy.

• a person who is being massaged, when asked to describe the sensation, reports a mixture of significant pleasure and mild pain when pressure is applied to very specific regions of their upper-back

In these and in similar cases, individuals involved are sensing, perceiving, remembering, and judging about their symptoms, body states, feelings, and sensations, and in some examples, reporting their experience to others. These are cognitive phenomena, but can ideas derived from symbolic logic and representationalist epistemology suffice to explain them? I would argue that there are a number of open questions about the utility of information-processing theories of body-knowledge.

Are the introspective reports, assessments, and statements generated by people about their body-state generally accurate, or not? What mechanisms account for the accuracy, or lack thereof?

To what extent do legacy concepts from cognitive science or information-processing models help or hinder the development of an understanding of how people access information and gain knowledge about their bodies?

How are we to understand the meaning(s) of the term “information” used to explain how and how well people know their own mental and physiological states? What is the relationship of “information” in the sense of physiological or biological systems to consciously reportable sensation, such that a person is getting information about their body state?

Are there many kinds of “information” involved in these models of internal state perception or “body cognition” found in clinical neurology, medicine, experimental psychology, and theoretical cognitive neuroscience? Or is there but one type of “information”, with different qualities or aspects that are described or measured in different ways?

How accurate are people at knowing what is happening inside their bodies?

Were people utterly inaccurate at judging their body state and reporting on it, clinical medicine would be deprived of a critical tool.  Evidence has accumulated that in certain circumstances, some people are evidently able to access information about the physiological processes inside of their bodies, and to report on it.  Experiments seem to demonstrate that some people are relatively accurate perceivers of symptoms or physiological state (Jones and Hollandsworth, 1981), (Adam, 1998), and that subjects can be ranked into good or poor estimators of internal state; for instance, with perceivers of heart rate (Schandry, 1981).

When we are actually aware of specific processes inside our bodies and can state this verbally, it would seem that in some fashion unconscious information (or unconscious “information”) has generated or has been transformed into knowledge. However, there is contradictory evidence about accuracy of symptom perception: how good people really are at perceiving various physiological states, and how accurate symptom-reports or other verbal-reports actually are. Many studies have yielded data consistent with the idea that people are not particularly good at accurately reporting on their symptoms or physiological states (Pennebaker, 1982). It is worth pointing out the assertion that people are generally inaccurate about knowing about physiological processes in their bodies reformulates the principle that humans lack epistemological privilege concerning introspective or verbally reported data. In considering the question: are we are likely to be in error when we report on the contents of what is in our minds, or not, it is critical to appreciate the persuasive interpretation of experiments written up in papers such as “Telling More than We Can Know” by the psychologists Robert Nisbett and Timothy Wilson (1977), which seems to show how introspection-based retroactive judgments can are in error.  This category of research typically features subjects placed in circumstances where their choices are influenced by variables controlled by experimenters, and who give explanations for their choosing that display incorrect “folk psychological” constructions. Nisbett and Wilson’s analysis can properly interpreted as to cast doubt on the ability of people to know the causes of our behavior and “higher order” information-processing, and can be summed up with their statement that people may possess “little ability to report accurately on their cognitive processes” (p. 246).

However, I assert that this valuable critique of retrospective judgments has been improperly extrapolated to support a broad skepticism about introspection, what I shall call the “received view” or the “overly skeptical view”, which I might sum-up as the belief that introspective data should generally be regarded with skepticism. As has been noted by careful researchers on introspection, (Schwitzgebel, 2006), this more general rejection of introspection certainly goes beyond what Nisbett and Wilson argued: while they do indeed assert that the evidence of numerous studies shows people are poor at using verbal report-based introspection to the cognitive process behind our judging and deciding, they do not support a general disdain for introspective data. Rather, they state that instead of arguing that introspective reports should simply be discredited, while people do not have introspective access to the cognitive processes, they do have such access to the contents of their cognitions. For instance, Nisbett and Wilson (pg. 255) state that introspection can yield forms of knowledge: knowledge about cognitive content, as an everyday person:

“…knows what his current sensations are and what almost all psychologists and philosophers would assert to be “knowledge” at least quantitatively superior to that of observers concerning his emotions, evaluations, and plans”

Furthermore, the “received view” that introspective reports are to be generally regarded with suspicion is in tension with the clinical use of patient introspection, as well as the high accuracy ratings sometimes displayed in experiments where subjects are asked to evaluate their own physiology. Therefore, while showing appropriate regard for data suggesting limits on introspective access to cognitive information (indeed I will suggest that models of body-knowledge should account for this data), I will nonetheless highlight certain clinical and experimental data that support the following assertion, which  contradicts the view that introspective data should be generally regarded with skepticism:

There exist cognitive processes that allow people to access internal body-state or physiological information in a way that enables fairly, or even highly, accurate verbal reports.  Insofar as this is true, people evidently have some degree of epistemologically privileged access to internal body state or interoceptive information. This relative privilege allows for knowledge of the body, as distinct from mere beliefs.

However, if this is true, some accounting of to what degree or how true it is, with which mitigating conditions, and with what reference to underlying cognitive and neurophysiological mechanisms would be necessary.  For that matter, even if true, demarcating the explanatory power of this principle relative to data adequately explained by the “received view” or “overly skeptical view” is of critical importance. It may be that only special or rare abilities are at issue here, and that the people who have privileged access to their internal physiological information are outliers.

History of the development of neurophenomenology-pt.1

(Part II is here, and Part III is here)

I will attempt in three essays to outline the sweep of ideas, researchers, and works that lead a few of us to speak of “neurophenomenology” as a more or less distinct field.  Part I traces 19th century psychology, neurology, and phenomenology roughly up to World War II. Part II examines the impact of cognitivism, the continued development of clinical neurology and basic neuroscience, the progression of phenomenological thought in psychology and medicine, and criticisms of cognitive science. Part III explores the early 1990’s origins of the emerging field of neurophenomenlogy within the broader context of interest in embodied cognition and consciousness studies. Any corrections, suggestions, or criticisms are welcome.

It may be too early to attempt a definitive characterization of the constitutive elements, at the least it is a combination of clinical studies by neurologists, psychiatrists, and psychologists, experimental work on the brain and mind, and philosophical analysis of consciousness and cognition. While the term “neurophenomenology” has a recent (early 1990’s) origin, the project of understanding the mysterious and profound relationship between brain events and awareness goes back at least as far as classical Greek philosophy. Physicians and philosophers have grappled with the enigma of existence and of consciousness for millenia. Psychology has roots in medicine, ethics, and the philosophy of mind and epistemology, but by the late 19th century,  the overlapping fields of biological psychology, psychiatry, behaviorism, and the psychophysiology and psychophysics of perception emerged. We can trace the series of research traditions that eventually developed  into “neurophenomenology” in the 1990’s through ideas and practices of  19th century researchers.  Understanding how these traditions drew from various sources, and subsequently interacted, requires we situate each field in then-current European disciplines. Elites were schooled in the Gymnasia, and acquired a broad and deep education before later specialization.  Physicians and/or laboratory experimentalists were expected to be familiar with classical and to an extent modern philosophy, and gentleman scholars would dabble in but also contribute to numerous fields: highly unlike the current hyper-specialization of academia. Psychology was very pluralistic at this stage: not yet fully divorced from philosophy, still possessing a sense that a field focusing on the richness and complexity of the human psyche must involve a study of consciousness.

There were numerous German psychophysics and psychological researchers looking for how consciousness and the brain were related, such as Herman von Helmholtz (1821-1894), Gustav Fechner (1801-1887), and Wilhelm Wundt (1832-1920).  Much effort was expended on rigorously correlating physiological and psychological measurements, resulting in establishing thresholds of perception and the limits of just noticeable differences. A number of laboratories used experimental methods where subjects told researchers what they were perceiving through verbal reports based on introspection.

Bold innovators like the justly renowned philosopher, psychologist and physician William James (1842-1910) also looked for the physical basis of experience. He pioneered research into neurology, performed psychological experiments, and made creative, yet disciplined, investigations into experiential aspects of mind. James’ use of crisp, lucid language describing consciousness and awareness pushed the threshold of what science, psychology, and philosophy could say about consciousness. James helped establish American experimental psychology, but really hit his stride with his still-fresh writings.  He described how memory and the enigmatic quality of the moment-by-moment flow of experience, and even wrote about altered states of consciousness. His central concept of consciousness being like a stream is still influential, and there is now a renewed appreciation for his work on how emotions are coupled to the physiological state of the body.  All in all, he is probably the most important figure in the history of American psychology. Yet his interdisciplinary boldness, penetrating curiosity and at times virtuostic powers of description of complex mental phenomena were not easily replicated by those researchers and younger colleagues he influenced.

William James, master theorist of consciousness

In the Principles of Psychology, James provided an admirably straightforward account of what introspection is:

“Introspective observation is what we have to rely on first and foremost and always. The word introspection need hardly be defined – it means, of course, looking into our own minds”

 

Fin-de-siecle psychophysics was in its golden years during his time, and while James’ wrote admiringly of the “philosophers of the chronometer” and other technically adroit experimental psychologists in his lab that measured perception and other phenomena, James himself continued his project of probing and describing the phenomenology of consciousness itself. While considered a father of introspectionist psychology and a forefather of both behaviorism and cognitive neuroscience, perhaps because of his hard-to-imitate brilliance, James did not leave a school of younger researchers to follow through on his research into consciousness.

In America, Europe, and Russia, generations of research into the organic basis of pathologies was reaching new heights of explanatory power. The German psychiatrist Emil Kraepelin (1856-1926) was formulating sophisticated theories of the physiological basis of mental illness in the early 20th century, in retrospect a crucial step in the early development of the now accomplished field we know as clinical neuropsychology. After each war, neurologists noted the correlations between location of trauma to the brains of the injured with deficits in speech, memory, movement, perception, affect,  emotion,and “body knowledge”. The Russian tradition culminated later in the influential work of Alexander Luria (1902-1977).

The force of new findings in clinical studies, physiology,  and experimental laboratory research eventually produced a scientific psychology that established itself as independent from moral philosophy, epistemology, metaphysics, and the philosophy of language. The success of  19th century psychophysics and neurophysiology, with breakthroughs such as Hermann von  Helmholtz‘s (1821-1894) measurement of the speed of the nerve impulse, provided ample justification for the fissure. Psychophysics experiments painstakingly produced data on the “just-noticeable difference” in light or stimulus intensity, etc. but there were real difficulties in establishing a consensus between the different laboratories on methodologies for dealing with subject’s reports on their perceptions.

While towering figures like Ernst Weber (1795-1878), Wilhelm Wundt (1832-1920), and Edward Titchener (1867-1927) were establishing a canon of principles and techniques for psychology, it proved extremely difficult to come up with one standard way to operationalize measurements that involved verbal reports about  subjective judgments and conscious experience. For all the brainpower deployed in various laboratories, by the 1930’s the tide was turning against scientific research into consciousness due to the influence of behaviorism, which reacted against the lack of an agreed-upon methodology in the German psychophysics-based psychology, especially involving introspection. The behaviorists marshaled an impressive array of experimental measurements techniques to establish causal relationships between stimulus and response, and then to infer lawlike generalizations. They stringently opposed the use of any mental concepts as inherently subjective and thus unscientific, and eschewed using first-person reports as much as possible. Within fields like the psychology of visual perception it was necessary to get verbal reports from subjects, but the behaviorists strove mightily to build a scientific psychology on purely physical principles. But if the behaviorists’ reacted against psychophysics for being insufficiently liberated from concerns with cognitive processes, others argued precisely the opposite. The philosopher Franz Brentano (1838-1917) wrote Psychology From An Empirical Standpoint in 1874, where he popularized the notion that the contents of experience constituted an important field of inquiry in their own right. Brentano’s influential theories of intentionality stressed the need to investigate the contents of awareness and their constitutive operations. Researchers working on cognition who were dissatisfied with the limitations of psychophysics ,and unpersuaded by the soon-to-be dominant anti-mentalist strictures of the behaviorists (such as physiologist Ivan Pavlov (1849-1936) and psychologist/advertising specialist John Watson (1878-1958))  rallied around this line of inquiry. Brentano made an impact among philosophers and psychologists and certain influential clinicians, and in some sense there is a diverse “School of Brentano“.

Arguably the most  influential among the students and followers of Brentano was the mathematician and philosopher Edmund Husserl (1859-1938). Husserl was fascinated (obsessed?) with the foundations of logic, mathematics, epistemology, and cognition.  Convinced by direct criticism from the celebrated logician Gottlob Frege (1848-1925) that psychological principles were epistemologically inadequate to foundationalize mathematical and logical truths, Husserl would eventually synthesize Brentano’s research into the primacy of intentional awareness within cognition with a quest for the undoubtable (or “apodictic”) core principles of mathematics, logic, and philosophy.  After producing light-reading classics such as Philosophie der Arithmetik, he developed a research program  into the first principles of cognition, logic, and epistemology called phenomenology.  While Husserl attracted many philosophers and certain psychologists to his cause with the 1900-1901 publication of the highly influential Logical Investigations, his continual probing of the constituent ideas underlying mathematical and logical truth was to an extent a solitary quest.

His acolytes and disciples found the Logical Investigations of great importance, yet they did not take up Husserl’s overarching project of a securing a logical foundation for all science, math, and philosophy. In the case of Martin Heidegger, phenomenology was redefined as the means for a still more fundamental investigation into ontology.

Edmund Husserl: logician, philosopher, and phenomenologist

Before WWII Husserlian phenomenology was perhaps the most important development in European philosophy, and influenced a number of other fields, such as psychology and medicine.Because his phenomenology took conscious experience as a source of data (following Brentano) many researchers interested in consciousness and cognition were excited by Husserl’s radically rigorous approach and penetrating exploration of how mental processes constitute, shape,  and structure the phenomena of which we are aware. His notion that cognition actively constructs the contents of awareness (compare to Jacob von Uexkull‘s (1864-1944) notion of the umwelt) would be familiar to modern cognitive neuroscientists but to early 20th century psychologists and philosophers was revolutionary. Husserl  influenced the philosophers Martin Heidegger (1889-1976), Jean-Paul Sartre (1905-1980), and Maurice Merleau-Ponty (1908-1961), the logician/mathematician Kurt Godel (1906-1978), the philosopher-theologian Karol Wojtyla (1920-2005), as well as (in more recent years) the prescient critic of Artificial Intelligence philosopher Hubert Dreyfus, and the cognitive neuroscientist Francisco Varela (1946-2001).

In America and Britain, these developments in Continental thought were generally of no interests to the behaviorists, who aside from biologically/medically-based critiques of the sort offered by neurologist Karl Lashley (1890-1958), enjoyed near-hegemony in scientific psychology. But eventually, the rise of computers led to the “cognitive revolution” : the  development of symbolic or information-processing theories of the mind that did not respect orthodox behaviorist’s strictures against the use of mental concepts.  In time, this  willingness to use mental concepts again would open the door to the study of consciousness in psychology and neuroscience . After WWII, the introduction  of computers led to cybernetic,  information-processing, symbolic-logical, and representational models of language, memory, behavior, reasoning, and even awareness.

(Part II is here, and part III is here)

more on the status of introspection in psychology and in neuroscience

An index of the status of introspection within psychology comes from Medin, Markman, and Ross (2004) in the textbook Cognitive Psychology, which notes (pg.20) that:

“Although introspection is not an infallible window to the mind, psychological research is leading to principles that suggest when verbal reports are likely to accurately reflect thinking”

These perspectives all can be said to implicitly or explicitly challenge what I shall call the “received view” or the “overly skeptical view”, which is an interpretation of the Nisbett and Wilson work that goes beyond what those authors’ famous paper actually said. While it is the case that the “Telling More than we can Know” Nisbett and Wilson paper argued persuasively that introspection-based reports of subjects asked to retrospect on the causes of their behavior are generally not accurate, these authors made a point of not dismissing the value of introspection and verbal reporting on the contents of cognition one is aware of , such as sensation or perception and “private facts”. But the “received view” of their research all too often neglects or ignores the more nuanced and balanced view about introspection of the authors, as well as that of other cognitive scientists who carefully investigated the issues involved, such as Anders Ericsson and Herbert Simon (1993).   This is an important concept: see Eric Schwitzgebel’s excellent take on the “Nisbett-Wilson myth“.

What is the most important concept to take away from the controversies about introspection? Probably it is that insofar as researchers want to be able to take advantage of all possible tools and data sources to make sense of the complex, enigmatic processes characterizing body knowledge, they should follow the example set by many physicians and some experimentalists, and be willing to get data by asking subjects or patients for their observations on body state. But here I will go one step further, and assert that the accuracy, or lack of accuracy, of verbal report data relative to other data, can serve as that which must be explained by a comprehensive and robust model of personal or self-reportable knowledge of the body. Doing so would require experiments where verbally reported data might be compared to, and possibly integrated with, data from external sources, such as from brain measurement: “neurophenomenology” in operationalized form.

One such effort came from a trio of researchers interested in assessing whether introspective data on pain had measurable neural correlates (Coghill, McHaffie, Yen, 2003, pg. 8538):

“Using psychophysical ratings to define pain sensitivity and functional magnetic resonance imaging to assess brain activity, we found that highly sensitive individuals exhibited more frequent and more robust pain-induced activation of the primary somatosensory cortex, anterior cingulate cortex, and prefrontal cortex than did insensitive individuals. By identifying objective neural correlates of subjective differences, these findings validate the utility of introspection and subjective reporting as a means of communicating a first-person experience”

This forward-looking research in effect turns behaviorism on its head: instead of verbal reports being rejected or at best tolerated within the overall context of strict objectivity, the very phenomenon the model seeks to explain is “subjective”!

Verbal report data: psychologists may be skeptical, but clinicians are more practical

Cognitive neuroscience and psychology needs to account for  verbal report data from people about their body states. In perceptual psychology and psychophysics experiments, in cognitive studies of human problem-solving, in clinical trials of drug efficacy and safety, in phenomenological-psychological investigations into the thematics of body experience, researchers routinely ask subjects or patients to answer questions. This is so common that its significance is perhaps under-appreciated. Science, at least in a narrow sense,  is conventionally understood to be based on objectively observable facts, not subjective opinions. But certain phenomena can not only be observed from the outside, as part of a system, but can also be reported on by people from the inside, as perceived or experiential events.

This regular use of the human self-reporting capacity is more remarkable in the light of intellectual history.  “Orthodox” cognitive science developed in the era of behaviorist dominance, and inherited certain skepticism about the trustworthiness of verbal reports, which are viewed as being sources of data, but not “privileged.” This stance indicates a rejection of older philosophical and psychological traditions that emphasized the use of introspection. Nonetheless, even in the time of behaviorist hegemony, psychologists still asked subjects questions in perception experiments, and clinicians have always used patient assessments to gain insight (Nahmias, 2002). While certain path-breaking cognitive scientists and psychologists explored the nature of introspection, and worked out the circumstances in which verbal reports could be authoritative and true accounts of aspects of cognitive processes (Erickson and Simon, 1991), (Ericsson, Chase, and Simon, 1979), the results of other widely cited experiments have been interpreted to denigrate introspective data, especially that of Nisbett and Wilson’s (1977) “Telling More than we can know” paper. Their research has been interpreted to indicate, for instance, that subjects made demonstrably inaccurate judgments about their underlying mental states because human beings apparently have little or no direct introspective access to the underlying cognitive processes of the mind (pg. 233):

“The accuracy of subjective reports is so poor as to suggest that any introspective access that may exist is not sufficient to produce generally correct or reliable reports.”

The interpretation of their data featured assertions that are now influential:  subjects lack  introspective access to the causal relationship between stimuli controlled by the experimenter and the verbal reports they produce. They are unable to accurately report which stimuli affected their responses. Rather, these verbal reports of effects of stimuli are based on unvalidated belief (such as naïve “folk psychological” theories about the causal connections between the stimuli and their response). Furthermore, if the reports on stimulus-response relationships are correct, it is because their naïve theories happen to be correct, and not because introspection gave them any privileged access to information. The upshot can be summarized as: subjects in situations with variables controlled by scientists make introspective judgments about why they behave in a particular manner or think a certain way, they state this explanation verbally to an experimenter, who can show the explanation to be false: (pg. 243)

“In order to test subject ability to report influences on their associative behavior, we had 81 male introductory psychology students memorize a list of word pairs. Some of these word pairs were intended to generate associative processes that would elicit certain target words in a word association task to be performed at a later point in the experiment. For example, subjects memorized the word pair “ocean-moon” with the expectation that when they were later asked to name a detergent, they would be more likely to give the target “Tide” than would subjects who had not previously been exposed to the word pairs….Immediately following the word association task, subjects were asked in open-ended form why they thought they had given each of their responses in the word association task. Despite the fact that nearly all subjects could recall nearly all of the words pairs, subjects almost never mentioned a word pair cue as a reason for giving a particular target response. Instead subjects focused on some distinctive feature of the target (“Tide is the best-known detergent”), some personal meaning of it (“My mother uses tide”), or an affective reaction to it (“I like the Tide box”).

The influence of this research has had the practical effect of renewing suspicions among psychologists and other researchers about introspective data, even if such methods continue to be used (Jack and Roepstorff, 2003) and despite the balanced view of Nisbett and Wilson where introspection has some utility regarding “sensations and/or private facts”, which takes into consideration the longtime use of introspective data as a method in psychology. Cognitive scientists, psychologists, physicians, and others can adopt their pragmatic distinction between the contents of cognition, such as sensations and emotions which can indeed be known and verbally reported, and the underlying causes, the information-processing or cognitive processes, which remain epistemologically inscrutable to introspection.

Yet while clinical medicine often regards introspective data with caution, it nonetheless uses it pragmatically. For instance, the standard neuropsychology text Clinical Neuropsychology (Heilman and Valenstein, 2003) states (pg.5)

“at times, patients’ observations of their own mental state may not only be helpful but necessary.”

This implies that it is a standard clinical methodology to use introspective data, and that patients have some useful access to their own minds.

This data-collection method of asking subjects and patients for self-reports is routinely used, according to psychologist Arthur Stone (Stone, 2000) (pg. 297):

“In both clinical practice and in research, the primary method of obtaining information about physical symptomology is through self-reports. Every day, thousands upon thousands of health care providers ask their patients to describe how they are generally feeling and too discuss specific symptoms. Patients present their doctors with panoply of global states (“I feel lousy,” “I am fatigued,” “I don’t feel right”) to very concrete descriptions (“I have a sharp pain in my right knee that is worse on awakening”). Information from these interviews, along with various medical tests, provides the basis for treatment and for the evaluation of its efficacy. In medical research, information of the same sort is obtained with questionnaires and structured interviews. These data-collection methods may provide a more systematic way of gathering physical symptom information, but regardless of the mode of data collection, the information is self-reported. Thus, reports of physical symptoms may be considered the mainstay of medical practice and research”

the legacy of Cartesian “objectivity” makes it hard to understand patient verbal reports

Psychiatrist Allan Beveridge (2002) hones in on a facet of the patient-physician relationship relevant to neurophenomenology: the over-adoption in medicine of the scientific attitude of objectivity towards phenomena. While entirely appropriate in the many research contexts, this may make understanding the personal body-knowledge of the patient more difficult (pg. 101):

“In the mental state examination, a standard method of describing the clinical encounter is to contrast the patient’s supposedly ‘subjective’ account with the doctor’s ‘objective’ description. In this model, the doctor is granted a privileged position: the clinician’s perspective is taken to be superior to that of the patient. The doctor’s objective approach is considered neutral, scientific and representing the truth of the matter. In contrast, the patient’s subjective report is regarded as unreliable, distorted and potentially false. The lowly status of the subjective perspective is further emphasized by the frequent use of the accompanying prefix, merely. On reflection, this dichotomy is an extraordinary one. It is held that the doctor is an authority on the patient’s inner experiences. The doctor knows more about how the patient is thinking and feeling than the patient him-/herself”

This “scientific” medical stance towards patient subjective reporting is consistent with the Cartesian heritage of the sciences of the mind. The implications, hidden or unexamined commitments should be critically examined if the verbal reports about patient body-states are to be better grasped by science and medicine. To the extent cognitive science, psychology, neuroscience, and medical fields uncritically base their methodologies on unexamined premises, certain problems may appear just due to the very choices of what is considered “data”. The relegation of patient verbal reports to the category of “merely subjective” allows for Cartesian assumptions about cognition to create difficulties at the outset of any research project attempting to model personal knowledge of the body. It may be that the very categories of subject and object, or scientific knowledge vs. subjective or “folk psychological” naïve theories of the body, present foundational problems for understanding how neurophysiological processes relate to verbally reportable knowledge of the body. But as a practical matter, health care professionals must simply cope with patient statements as one more data source (Ersser and Atkins, 2000, pg. 68):

“Clinical decisions involve information of a necessary type and quality. Professionals take account of both objective and subjective data during the clinical assessment process to decide on a patient’s health care need and care plan. The difficulty lies in professionals understanding how best to reconcile their objective perspective with that of the patient, when formulating clinical judgments”

Before a doctor revives technical training, he or she is a person with experiences of health and sickness. The verbal reports of patients are interpreted by professionals with their own history of embodiment. To what extent does their personal body knowledge consciously or unconsciously affect their clinical intuition about the accuracy of patient verbal reports? Does expert knowledge of the body gained from studying anatomy and physiology allow for better knowledge of one’s own body? Such questions point to our current rather murky understanding of embodied cognition, underscoring the need for models capturing richer, more subtle aspects of experience, cognition, and brain.

symptom verbal reports and existential-physiological discrepancy

While the anatomical basis of how nerve projections enable perception of the body is rather well known, physicians confront situations where patient verbal reporting about symptoms does not match models based on neurophysiological mechanisms. For instance, the Merck Manual Medical Library (2009) states:

“Painful stimuli from thoracic organs can produce discomfort      described as pressure, gas, burning, aching, and sometimes sharp pain. Because the sensation is visceral in origin, many patients deny they are having pain and insist it is merely discomfort”

The Mayo Clinic Heart Book (Gersh, 2000) describes the concept of uncomfortable feeling of thumping inside the chest known as palpitations, but does so from the point of view of patients (pg. 38):

“Although the apparent cause of the thumping in the chest would seem to be the heartbeat, this is not always the case. Some people have a normal heart rate during their palpitations. Presumably, they are either anxious or experiencing chest wall twitching that is mistaken for heartbeats”

Situations where the “folk physiological” (see Churchland, 1989, for a description of expert knowledge vs. folk beliefs) understanding of the body is apparently falsified by science can be labeled examples of existential-physiological discrepancy (Laughlin, McManus, D’Aquili, 1990). Mismatches between body-as-experienced compared to the “objective body” of scientific medicine and physiology (including the feeling of “phantom limbs” by amputees) are based on the idea that people may often have very limited “true” access to physiological processes. A more commonly presented variant or subset of this principle is the idea of “referred pain”, where the region causing understood to be causing the pain is spatially removed from the area where the patient senses it.

The Merck Manual (2009) gives an example: sometimes pain felt in one area of the body does not accurately represent where the problem is, because the pain is referred there from another area. Pain can be referred because signals from several areas of the body often travel through the same nerve pathways in the spinal cord and brain. For example, pain from a heart attack may be felt in the neck, jaws, arms, or abdomen. Pain from a gallbladder attack may be felt in the back of the shoulder.

Jack and Roepstorff on introspection

From Trusting the Subject (2003), Anthony Jack and Andreas Roepstorff write:

“The unique challenge facing a science of consciousness is that that the best instrument available for measuring experience depends on cognitive processes internal to the subject. So just how much faith can we place in the capacity of the mind to understand itself? In principle, the construction of a maximally robust methodology for introspective evidence would require a detailed understanding of the operation of introspective processes — the processes that mediate the acquisition of introspective knowledge and underlie the production of introspective reports”

And:

“It is important to realize that no principled problem stands in the way of the scientific assessment of various types of introspective evidence. The testing of the reliability, consistency and validity of various types of introspective report measures lies well within the orbit of currently available methods. A measure may be called ‘reliable’ if it yields the same results when tested in multiple sessions over time (‘test–retest reliability’) and across individuals (a cousin of ‘inter-rater’ and ‘inter-observer’ reliability). Of course, subjects’ reports may differ, and so appear to be unreliable, simply because their internal mental processes and states vary. Thus it is critical to establish well controlled experimental conditions for eliciting reports. The considerable advances in behavioural science since the time of the Introspectionists offers experimenters considerable advantages in this regard (see Ericsson, this volume). Not only do these advances make it much more probable that experimenters can establish conditions under which introspective measures can be shown to be reliable, they also provide much greater insight into the behavioural and neural correlates of experiential phenomena.

A measure may be called ‘consistent’ when it can be shown that the results are not due to specific features of the measurement technique. Tests of consistency provide a means of checking that the observed effect is not due to a methodological artefact. Thus we might test the consistency of introspective  evidence by comparing immediate forced-choice button-press reports with retrospective and open-ended verbal reports. In this way we might establish, for instance: that the results of forced-choice button-press reports have not been influenced by variations in the criterion for response or by automatisation of response such that they no longer constitute true introspective reports; and that retrospective reports have not been distorted by forgetting or memory interference effects.

‘Validity’ is the most important factor to establish, yet it is also the most theoretically complex, and a particularly vexed issue in cognitive science. A measure is validated when it can be shown to accurately reflect the phenomenon it purports to measure. Validity is complex because scientific measures are often simultaneously interpreted as providing evidence for phenomena at a number of
different levels. A rough characterisation of three major sources of evidence in cognitive science might read as follows:

-Data from functional Magnetic Resonance Imaging (fMRI) serves most directly as evidence of cerebral blood flow (which has been validated), less directly as evidence for neural activity (which is in the process of being properly validated), and least directly as a means of identifying and localising specific cognitive functions (far from well validated).

– Behavioural measures (e.g. the averaging of reaction time measures over multiple trials) serve most directly as evidence for stable patterns of behaviour, less directly as a means of assessing information processing, and least directly as means of establishing the existence and operation of specific cognitive functions.

-Introspective reports serve most directly as evidence about the beliefs that subjects have about their own experience, less directly as evidence concerning the existence of experiential phenomena, and least directly as evidence concerning the operation of specific cognitive functions.