A model of the neuropsychology of anxiety is proposed. The model is based in the first instance upon an analysis of the behavioural effects of the antianxiety drugs in animals. From such psychopharmacologi-cal experiments the concept of a “behavioural inhibition system” has been developed. This system responds to novel stimuli or to those associated with punishment or nonreward by inhibiting ongoing behaviour and increasing arousal and attention to the environment. It is activity in the BIS that constitutes anxiety and that (...) is reduced by antianxiety drugs. The effects of the antianxiety drugs in the brain also suggest hypotheses concerning the neural substrate of anxiety. Although the benzodiazepines and barbiturates facilitate the effects of γ-aminobutyrate, this is insufficient to explain their highly specific behavioural effects. Because of similarities between the behavioural effects of certain lesions and those of the antianxiety drugs, it is proposed that these drugs reduce anxiety by impairing the functioning of a widespread neural system including the septo-hippocampal system, the Papez circuit, the prefrontal cortex, and ascending monoaminergic and cholinergic pathways which innervate these forebrain structures. Analysis of the functions of this system suggests that it acts as a comparator: it compares predicted to actual sensory events and activates the outputs of the BIS when there is a mismatch or when the predicted event is aversive. Suggestions are made as to the functions of particular pathways within this overall brain system. The resulting theory is applied to the symptoms and treatment of anxiety in man, its relations to depression, and the personality of individuals who are susceptible to anxiety or depression. (shrink)

Drawing on previous models of anxiety, intermediate memory, the positive symptoms of schizophrenia, and goal-directed behaviour, a neuropsychological hypothesis is proposed for the generation of the contents of consciousness. It is suggested that these correspond to the outputs of a comparator that, on a moment-by-moment basis, compares the current state of the organism's perceptual world with a predicted state. An outline is given of the information-processing functions of the comparator system and of the neural systems which mediate them. The hypothesis (...) appears to be able to account for a number of key features of the contents of consciousness. However, it is argued that neitherthis nor any existing comparable hypothesis is yet able to explain why the brain should generate conscious experience of any kind at all. (shrink)

The first claim in the target article was that there is as yet no transparent, causal account of the relations between consciousness and brain-and-behaviour. That claim remains firm. The second claim was that the contents of consciousness consist, psychologically, of the outputs of a comparator system; the third consisted of a description of the brain mechanisms proposed to instantiate the comparator. In order to defend these claims against criticism, it has been necessary to clarify the distinction between consciousness-as-such and the (...) contents of consciousness, to widen the description of the neural machinery instantiating the comparator system, and to clarify the relationship between the contents of consciousness in the here-and-now and episodic memory. (shrink)

[opening paragraph]: Imagine you are a scientist from Mars observing Gary Kasparov playing a tournament with a chess computer. Would you have any reason to postulate consciousness in one player, but not the other? What is consciousness? How does the body produce it, and what is it for? Most people do not realize that there is a problem here because our conscious experience is the thing we know best. We are all familiar with the colours, smells and scenes around us, (...) the pains and itches we feel and the thoughts that are in our heads. Our world consists of conscious experiences. By `conscious experience' I mean anything that you have an awareness of, absolutely anything. I do not mean anything recondite like your capacity to reflect upon your own experiences, something which one might suppose that only we as human beings have and animals do not. I mean the absolute basics, like feeling pain. (shrink)

As well as data indicating relationships (emphasised in the target article) (1) between dopaminergic transmission in the nucleus accumbens and positive incentive motivation, and (2) between dopaminergic transmission and extraversion, other data (not accounted for by the hypotheses developed in the target article) indicate relationships (3) between accumbens dopaminergic transmission and cognitive, especially perceptual, processes that are disrupted in schizophrenia, and (4) between dopaminergic transmission and psychoticism. The tension between relationships 1 + 2 and 3 + 4 is discussed and (...) a tentative resolution proposed. (shrink)

The use of neural transplantation to alleviate cognitive deficits is still in its infancy. We have an inadequate understanding of the deficits induced by different types of brain damage and their homologies in animal models against which to assess graft-induced recovery, and of the ways in which graft growth and function are influenced by factors within the host brain and the environment in which the host is operating. Further, use of fetal tissue may only be a transitory phase in the (...) search for appropriate donor sources. Nevertheless, findings from our laboratory and elsewhere have made a prima facie case for successful cognitive reconstruction by graft methods. (shrink)

Cognitive deficits were produced in rats by different methods of damaging the brain: chronic ingestion of alcohol, causing widespread damage to diffuse cholinergic and aminergic projection systems; lesions (by local injection of the excitotoxins, ibotenate, quisqualate, and AMPA) of the nuclei of origin of the forebrain cholinergic projection system (FCPS), which innervates the neocortex and hippocampal formation; transient cerebral ischaemia, producing focal damage especially in the CA1 pyramidal cells of the dorsal hippocampus; and lesions (by local injection of the neurotoxin, (...) colchicine) of the granule cells of the dentate gyrus. Following chronic alcohol or lesions of the FCPS, transplants of cholinergically rich fetal brain tissue into the terminal areas (neocortex and/or hippocampus) restored performance almost to control levels, with a time course consistent with growth of the transplants and integration with host tissue; transplants of cholinergically poor fetal tissue (hippocampus) were without effect, as were transplants of cholinergically rich tissue into the region containing the nuclei of origin of the FCPS. Grafts of primary cells enriched in glia and cultured neuroblastoma cells into the terminal areas of the FCPS were equally effective, suggesting that there are multiple mechanisms by which neural transplants can restore cognitive function following diffuse cholinergic damage. In contrast, after ischaemia- or neurotoxin-induced damage to CA1 or dentate granule cells respectively, cholinergically rich fetal transplants into the damaged hippocampal formation were ineffective in restoring performance. After ischaemic damage, however, performance was restored by suspension grafts of CA1 cells but not by transplants containing CA3 pyramidal cells or granule cells; and after colchicine damage it was restored by solid grafts containing granule but not CA1 pyramidal cells. Furthermore, electrophysiological evidence has demonstrated functional, graft type-specific host-graft functional neuronal connectivity. Thus, restoration of cognitive function by neural transplants is possible after damage to either diffuse (cholinergic) or point-to-point (intrahippocampal) forebrain systems, but the transplant must be appropriate to the damage to be repaired. Because the different types of brain damage studied provide analogues of human alcoholic dementia, Alzheimer's disease, and heart attack, these results are encouraging with regard to the eventual application of neural transplant surgery to the treatment of cognitive deficits in humans. (shrink)

How does conscious experience arise out of the functioning of the human brain? How is it related to the behaviour that it accompanies? How does the perceived world relate to the real world? Between them, these three questions constitute what is commonly known as the Hard Problem of consciousness. Despite vast knowledge of the relationship between brain and behaviour, and rapid advances in our knowledge of how brain activity correlates with conscious experience, the answers to all three questions remain controversial, (...) even mysterious. This important book analyses these core issues and reviews the evidence from both introspection and experiment. To many its conclusions will be surprising and even unsettling: * The entire perceived world is constructed by the brain. The relationship between the world we perceive and the underlying physical reality is not as close as we might think * Much of our behaviour is accomplished with little or no participation from conscious experience. * Our conscious experience of our behaviour lags the behaviour itself by around a fifth of a second - we become aware of what we do only after we have done it. * The lag in conscious experience applies also to the decision to act - we only become aware of our decisions after they have been formed. * The self is as much a creation of the brain as is the rest of the perceived world. Written by a leading scientist, this accessible and compelling analysis of how conscious experience relates to brain and behaviour will have major implications for our understanding of human nature. (shrink)

What makes conscious experiences necessary for in- formation processing or behaviour (no one knows)? Would it be easier first to divide consciousness into different levels (probably not)? Is consciousness tied to information processing or brain states (no one knows)? Would the target article's comparator be improved by adding a continuously adjusting feedback (probably not)?

This Editorial reports an exchange in form of a comment and reply on the article “History and Nature of the Jeffreys–Lindley Paradox” (Arch Hist Exact Sci 77:25, 2023) by Eric-Jan Wagenmakers and Alexander Ly.

Because consciousness has an organizational, or functional, center, Gray supposes that there must be a corresponding physical center in the brain. He proposes further that since this center generates consciousness, ablating it would eliminate consciousness, while leaving behavior intact. But the center of consciousness is simply the product of the functional linkages among sensory input, memory, inner speech, and so on, and behavior.

In lieu of an abstract, here is a brief excerpt of the content:The Triumph Of SisyphusJeffrey GordonThe gods had condemned Sisyphus to ceaselessly rolling a rock to the top of the mountain, whence the stone would fall back of its own weight. They had thought with some reason that there is no more dreadful punishment than futile and hopeless labor.1The words are, of course, Albert Camus's. They were first published in 1942. Since then, this voice—at once lyrical and austere, personal (...) and oracular—and the ancient image he calls up in these lines have become permanent parts of our postmodern consciousness. Like all the images that capture and create the character of our age, Sisyphus is always there for each of us. In the intimate space of our imagination, we can turn to him at will, and with only the slightest effort, we will find him as before—solitary, weather beaten, resigned, without illusion. I want to make that effort now, not to disturb Sisyphus in his labors, nor to uproot him, surely, but to try to be precise about a matter which is, perhaps, fatally elusive of precision, to try to make explicit the significance of this figure whose implicit significance has haunted us now for over half a century. Let us turn to Sisyphus, then, as we might turn, one aimless afternoon, to some old photographs of a person close to us, perhaps even of ourselves, in the hope that we might find in them something we had missed, some expression or gesture that inadvertently reveals the essence of a life.But we must be silent now, for the figure is emerging. There is the hill, and it is morning, a slight chill in the soundless air. The landscape here is treeless, the land covered only with broken rock and scattered brush. A wide path of sterile earth has been cut in the thick brush of [End Page 183] the hill. And there, at the base of the hill, the rock—grey, mottled with holes, enormous. Slow, laborious breathing is audible. The rough hand comes into view, the flesh thick, sun-burnt, heavily veined. It finds a jut on the rock to grip. And now the weather-worn clothes, the thick trunk and powerful back. And here at last the face of Sisyphus—our own face, of course, or the face of one of our own personae, the eyes squinting against the sun, hair disheveled. He takes his hand from the rock and brings it to his side. Perhaps he is not quite ready yet, perhaps he needs a moment longer of rest. He stands motionless, eyes turning up. What is he gazing at? The summit of the hill, every square inch of which he has seen a million times before? What could he hope to discover there? Is it the cloudless sky that has his attention? Is he noting the progress of the sun? Does he seek in reflection on its course some inspiration for the renewal of his labor? He continues to stare without expression. We can afford to leave him for a moment.The legend abounds in perplexities, or at least this is true of that retelling of the myth that has made it so important to us. Camus calls Sisyphus "the absurd hero." This is, then, the best that we can hope to be, for our lives, too, according to Camus, are absurd. But why should we believe this? Surely it is ludicrously question-begging to conduct an imaginative exercise in which we strip a life of all that could possibly make it worthwhile, then appeal to this figment of ours as proof of the futility of human existence.If we are tempted to see in Sisyphus's eternal rock-rolling a revelation of the emptiness of our own labors, we should be easily dissuaded from this when we consider what little alteration is required to transform this myth from the perfect image of meaninglessness to a perfectly serviceable conception of a meaningful life.2 All we need is to introduce some point, some minimal, common, everyday point to his labors, such as any one of our lives abounds in, and the transformation is accomplished. Assume, then, that Sisyphus rolls... (shrink)

Jeffrey Gray’s Consciousness: Creeping up on the Hard Problem will be enjoyed by everyone interested in consciousness. Gray, a neuropsychologist, eloquently summarizes significant experimental results on consciousness and, more importantly, explains both how these results interrelate and how they constrain potential theories of consciousness. He also uses these results to build a novel, fascinating theory of what consciousness does and does not do. Throughout the work Gray’s accessible presentation remains deeply respectful of psychologists, neuroscientists, and philosophers’ (...) approaches to consciousness. In this respect, Gray’s book is an ideal work for an interdisciplinary audience. Sadly, Gray died three months before the publication of this excellent work. (shrink)

Since Francis Crick popularized the term `Neural Correlate of Consciousness' (NCC), it has been the focus of what is perhaps the most exciting research area in the cognitive sciences. Different researchers and laboratories have offered different brain structures as candidates for the NCC prize. Different chunks of gray matter have been identified as the potential seat of consciousness. Some researchers attempt to identify the NCC via a characterization of the cognitive aspects of consciousness, such as its functional significance or (...) intentional directedness, while others attempt a direct identification of the NCC, without any cognitive intermediary. Needless to say, no consensus is in sight on any of this. (shrink)

There has been a spate of books recently on the subject of consciousness. Relatively few of these, however, have taken a serious look at the philosophical issues surrounding the study of consciousness. Jeffrey Foss's book Science and the Riddle of Consciousness: A Solution is a welcome exception.

Many strands are woven into the ideas and work of Jeffrey Gray. From a background of classical languages and a spell in military intelligence spent honing skills in languages and typing, he took two BA degrees (in modern languages and psychology) at Oxford University. He then trained as a clinical psychologist at the Institute of Psychiatry (IOP), London, capping this with a PhD on the sources of emotional behaviour.

Machine generated contents note: 1.What is a Concept? -- 2.Why Philosophy? -- 3.How to Become a Philosopher -- 4.Putting Philosophy in its Place -- 5.Philosophy and Science -- 6.Philosophy and Logic -- 7.Philosophy and Art.

We consider two ways one might use algorithmic randomness to characterize a probabilistic law. The first is a generative chance* law. Such laws involve a nonstandard notion of chance. The second is a probabilistic* constraining law. Such laws impose relative frequency and randomness constraints that every physically possible world must satisfy. While each notion has virtues, we argue that the latter has advantages over the former. It supports a unified governing account of non-Humean laws and provides independently motivated solutions to (...) issues in the Humean best-system account. On both notions, we have a much tighter connection between probabilistic laws and their corresponding sets of possible worlds. Certain histories permitted by traditional probabilistic laws are ruled out as physically impossible. As a result, such laws avoid one variety of empirical underdetermination, but the approach reveals other varieties of underdetermination that are typically overlooked. (shrink)

Introduction -- 1. Problem of the New -- 2. Problem of Relations -- 3. Problem of Emergence -- 4. Problem of One and Many -- 5. Plato and the Third Man Argument -- 6. Bradley and the Problem of Relations -- 7. Moore, Russell and the Birth of Analytic Philosophy -- 8. Russell and Deleuze on Leibniz -- 9. On Problematic Fields -- 10. Kant and Problematic Ideas -- 11. Armstrong and Lewis on the Problem of One and Many -- (...) 12. Determinables and Determinates -- 13. The Limits of Representational Thought -- 14. Learning from a Cup of Coffee -- 15. Carnap and the Fate of Metaphysics -- 16. Truth and Relevance -- Conclusion. (shrink)

Despite the fact that time, evolution, becoming and genealogy are central concepts in Deleuze's work, there has been no sustained study of his philosophy in relation to the question of history. This book aims to open up Deleuze's relevance to those working in history, the history of ideas, science studies, evolutionary psychology, history of philosophy and interdisciplinary projects inflected by historical problems.The essays in this volume cover all aspects of Deleuze's philosophy and its relation to history, ranging from the application (...) of Deleuze's philosophy to historical method, Deleuze's own use of the history of philosophy, his interpretations of other historical thinkers and the complex theories of time and evolution in his work.Contributors include: Paul Patton, Manuel DeLanda, John Protevi, Ian Buchanan, Tim Flanagan, James Williams, Eve Bischoff, Jay Lampert. (shrink)

David Hume’s skeptical solution to the problem of induction was grounded in his belief that we learn by means of custom. We consider here how a form of reinforcement learning like custom may allow an agent to learn how to learn in other ways as well. Specifically, an agent may learn by simple reinforcement to adopt new forms of learning that work better than simple reinforcement in the context of specific tasks. We will consider how such a bootstrapping process may (...) lead to a system that includes trial-and-error forms of learning like win-stay/lose-shift, probe and adjust, and simple reinforcement itself together with higher-rationality inferential tools. (shrink)

Françios Viète was a geometer in search of better techniques for astronomical calculation. Through his theorem on angular sections he found a use for higher-dimensional geometric magnitudes which allowed him to create an algebra for geometry. We show that unlike traditional numerical algebra, the knowns and unknowns in Viète’s logistice speciosa are the relative sizes of non-arithmetized magnitudes in which the “calculations” must respect dimension. Along with this foundational shift Viète adopted a radically new notation based in Greek geometric equalities. (...) His letters stand for values rather than types, and his given values are undetermined. Where previously algebra was founded in polynomials as aggregations, Viète became the first modern algebraist in working with polynomials built from operations, and the notations reflect these conceptions. Viète’s innovations are situated in the context of sixteenth-century practice, and we examine the interpretation of Jacob Klein, the only historian to have conducted a serious inquiry into the ontology of Viète’s “species”. (shrink)

Sagvolden, Johansen, Aase, and Russell (Sagvolden et al.) examine attention-deficit/hyperactivity disorder (ADHD) at levels of analysis ranging from neurotransmitters to behavior. At the behavioral level they attribute aspects of ADHD to anomalies of delay-of-reinforcement gradients. With a normal gradient, responses followed after a long delay by a reinforcer may share in the effects of that reinforcer; with a diminished or steepened gradient they may fail to do so. Steepened gradients differentially select rapidly emitted responses (hyperactivity), and they limit the effectiveness (...) with which extended stimuli become conditioned reinforcers, so that observing behavior is less well maintained (attention deficit). Impulsiveness also follows from steepened gradients, which increase the effectiveness of smaller, more immediate consequences relative to larger, more delayed ones. Individuals who vary in the degree to which their delay gradients are steepened will show different balances between hyperactivity and attention deficit. Given the range of ADHD phenomena addressed, it may be unnecessary to appeal to additional behavioral processes such as extinction deficit. Extinction deficit is more likely a derivative of attention deficit, in that failure to attend to stimuli differentially correlated with extinction should slow its progress. The account suggests how relatively small differences in delay gradients early in development might engender behavioral interactions leading to very large differences later on. The steepened gradients presumably originate in properties of neurotransmitter function, but behavioral interventions that use consistently short delays of reinforcement to build higher-order behavioral units as a scaffolding to support complex cognitive and social skills may nonetheless be feasible. Key Words: ADHD; attention deficit; delay gradient; exponential decay; extinction deficit; hyperactivity; impulsiveness; intervention; observing responses; self-control. Footnotes1000 Jeffrey Gray was the BBS Editor for this treatment. When he accepted Sagvolden et al. for publication, he invited Catania, who was one of the reviewers of the original submission, to prepare a precommentary. Com-mentators were then invited to respond to the Sagvolden et al. article, to the Catania precommentary, or to both. (shrink)

Introduction -- Making sense of life -- communication problems -- Making sense of politics -- Stop making sense -- Towards a critical existentialism.

The Central American country of Guatemala committed itself to democratic values and processes in its election of December, 1985. Guatemala, like most other Central American countries, has been through the dictator-constitution-election revolving door many times. For almsot half a century, Guatemala has been afflicted with coups, general-presidents and dictator-presidents. Again, in 1985, Guatemala created a new constitution with provision for democratic presidential elections monitored and declared "democratic" by a score of other nations. The new president, Vinicio Cerezo, and his Minister (...) of Education, Eduardo Meyer Maldonado, emphasized that the elementary school, the only formal educational institution attended by the majority of Guatemalans, must provide those learning experiences required to develop, to nourish and to sustain democracy in Guatemala. (shrink)