ON CONSCIOUSNESS

Science & Subjectivity - Updated Works on Global Workspace Theory

Bernard J. Baars, Natalie Geld

• Éditeur: Nautilus Press
• Année: 2020
• ISBN:
  9781732904897
• Édition: 1
• Sujet: Psychology
• Sous-sujet: Cognitive Psychology & Cognition

" The works of Bernard Baars collected here are among the foundational texts of the scientific study of consciousness. Their influence in cognitive science and philosophy of mind is enormous, and their impact on my own thinking has been profound." —Murray Shanahan, Professor of Cognitive Robotics, Dept of Computing, ICL

Global Workspace Theory (GWT) began with this question: “How does a serial, integrated and very limited stream of consciousness emerge from a nervous system that is mostly unconscious, distributed, parallel and of enormous capacity?”

GWT is a widely used framework for the role of conscious and unconscious experiences in the functioning of the brain. A set of explicit assumptions that can be tested, as many of them have been. These updated works, from the recipient ofINNS 2019 Hermann von Helmholtz Life Contribution Award, form a coherent effort to organize a large and growing body of scientific evidence about conscious brains.

Throughout human history, people have perceived the conscious brain as the great nexus of human life, of social relationships, of their personal identities and histories, in encounters with new challenges. Consciousness under its many labels and manifestations is widely seen to be one of the core mysteries of life. Many therapeutic approaches can be viewed in a global workspace framework, including traditional psychodynamics and depth psychology, but also cognitive behavioral techniques, and, indeed, many other kinds of carefully studied human functions. Making progress in understanding consciousness therefore has an endless number of implications - philosophical, metaphysical, scientific, medical, clinical, and practical.

A valuable reference for technical audiences and a vigorous intellectual hike for the layman." — Kirkus Reviews

How can we understand the evidence? The best answer today is a ‘global workspace architecture, ’ first developed by cognitive modeling groups led by Alan Newell and Herbert A. Simon. The term “global workspace” comes from Artificial Intelligence, where it refers to a fleeting memory domain that allows for cooperative problem-solving by large collections of specialized programs. Global Workspace Theory (GWT) therefore assumes that the brain can be viewed as a "society of mind."

Global Workspace (GW) theoryis consistent with our current knowledge, and can be enriched to include other aspects of human experience.

• Stan Franklin and co-workers have built on GWT to sketch out a more general theory of cognition -LIDA: Cognitive Architecture's Computational Implementation of GWT.
• Stanislas Dehaene and Jean-Pierre Changeux in Paris developed experimentally testable models, making further testable claims about the brain basis of visual consciousness - The Dehaene-Changeux Model (DCM): Global Neuronal Workspace is Part of GWT.

PART I.

Consciousness Explored: Making sense of the evidence

Introduction

Why do some people deny consciousness?

What is the silliest claim ever made? The competition is fierce, but I think the answer is easy. Some people have denied the existence of consciousness: conscious experience, the subjective character of experience, the “what-it-is-like” of experience.

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— Galen Strawson, Professor, Department of Philosophy, University of Texas at Austin.

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Debates about consciousness and personal identity can be found in our earliest writings, in languages like ancient Greek and Sanskrit. Field anthropologists have reported dozens of “culturally universal” beliefs about waking consciousness, dreams, and personal identity (Brown, 1991). Mental terms make up more than half of our natural language vocabularies. Even before the first millennium BCE we can read about conscious experiences, often in nightly dreams, or as a soul journey after death.

In a 4th century BCE treatise of the Hippocratic Corpus, perhaps the oldest medical textbook we have, is a clinical study of the epilepsies by the School of Hippocrates. It points unambiguously to a brain basis for conscious experiences:

“Men ought to know that from the brain, and from the brain alone, arise our pleasures, joys, laughter and jests, as well as our sorrows, pains, griefs and tears. Through it, in particular, we think, see, hear and distinguish the ugly from the beautiful, the bad from the good, the pleasant from the unpleasant... I hold that the brain is the most powerful organ of the human body... wherefore I assert that the brain is the interpreter of consciousness…” (School of Hippocrates: On the Sacred Disease.)

Like Hippocrates, modern scientists see two separate sources: The individual experiences of subjects as they describe them, and the marks of those experiences in the brain and behavior. Modern brain evidence goes back at least to Wilder Penfield in the 1950s and indeed to Santiago Ramón y Cajal circa 1900. Our psychological evidence can be traced to William James and his century in Europe and America.

Since the rise of neuroimaging our brain evidence has improved spectacularly, and the biological basis of subjectivity has now become a recognized goal in the sciences. Far from contradicting each other, public and private evidence is generally mutually supportive. The conscious sight of a red object has distinctive and increasingly clear bases in the brain. Thus the historic separation between psychology and brain physiology may be changing into a unified mind-brain science.

Even so, consciousness science still resembles sex in the Victorian age: We know it’s there, but we tend to evade it. Some scientists still wonder out loud if they themselves are really conscious. In Things That Bother Me: Death, Freedom, the Self, etc., philosopher Galen Strawson writes:

When it comes to conscious experience, there’s a rock-bottom sense in which we’re fully acquainted with it just in having it. The having is the knowing. So when people say that consciousness is a mystery, they’re wrong — because we know what it is. It’s the most familiar thing there is — however hard it is to put into words.

…What people often mean when they say that consciousness is a mystery is that it’s mysterious how consciousness can be simply a matter of physical goings-on in the brain. But here, they make a Very Large Mistake, in Winnie-the-Pooh’s terminology—the mistake of thinking that we know enough about the physical components of the brain to have good reason to think that these components can’t, on their own, account for the existence of consciousness. We don’t.

Scientists cannot avoid the three fundamental questions of subjective experience, voluntary control and personal identity. Yet for seven decades in the 20th century the behavioristic movement mounted a remarkably successful campaign to exclude those questions as ‘unscientific.’ That taboo started to lift in the 1970s and 80s, but many of our technical terms still reflect the old biases.

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The misnamed “resting state” is really the active Stream of Consciousness (SoC).

Scientists sometimes mis-use the term “default state” or “resting state” when subjects are asked to do nothing in particular. But good observers have known for thousands of years that we cannot really stop the flow of thoughts, feelings, memories, emotions, and plans, whenever we are conscious, even without an experimental task. Social psychologists have known for decades that the spontaneous Stream of Consciousness (SoC) is not a zero activity state.

Rather, Jerome L. Singer and many others have shown that we spontaneously think about our “current concerns,” our worries and high priority plans, about our relationships problems, or upset at something that made us angry or embarrassed, or we are just struggling to stay awake. If we have no experimental task to perform, we often go into fantasy states, or even into drowsy twilight dreams, and a substantial percentage of the general population spends hours immersed in fantasies, always about personally important things, of course.

Post-traumatic stress disorder (PTSD) is indeed defined by spontaneous thought intrusions, especially unwanted and upsetting thoughts, which can happen even with apparently minor upsets. What seems minor to an outsider may be major to a human being in a brain recording machine. If neuroscientists asked their subjects to give simple thought reports at random times during the so-called “resting state” they would find out how active our conscious waking state really is. Trauma-related thoughts are surprisingly common in the general population, and the adolescent population is especially vulnerable to daily ups and downs of moods and worries about others. There is really a range of “trauma intensity” which does not have to involve “major life events” as judged by others. Feeling rejected by a social group can also lead to intrusive conscious thoughts.

The reason why the brain shows more activity during the “default” state than in experimental tasks (which are often extremely boring), is that the spontaneous SoC does much more important work for us than the usual experimental tasks. Counting backwards by threes from some arbitrary number is not a thrilling task, and most experiments are personally irrelevant to our subjects. Consciousness is a major biological function, and the chronobiological regulation of waking, dreaming and sleep suggests that even physically passive consciousness is highly functional.

Twenty years ago Cirelli and Tononi discovered more than 200 epigenetic correlates with the three basic brain states, suggesting vital biological functions for waking, sleep and dreaming. We mull things over consciously for good reasons, which is why the waking conscious state is such a large biological phenomenon. The particular reasons why we feel fear or anger at any given moment in the spontaneous SoC is often unknown. But careful thought monitoring studies show that our apparently random thoughts usually reflect major life issues, especially those that are unresolved.

The SoC has been discussed exquisitely by Marcel Proust, James Joyce, Virginia Woolf, William and Henri James, the phenomenologist, and, of course, the contemplative traditions in Asia and Europe and in hunter-forager tribes. The Andaman Islanders have the “dream time,” and dreaming (including lucid dreams and dream paralysis), routine topics in pre-settlement cultures. They occur spontaneously, no need even to teach people to do it, because some people discover it spontaneously.

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Language is both conscious and nonconscious. Most brain functions seem to be unconscious, so that even the fleeting conscious present is embedded in multiple unconscious processing threads, which precede, interpenetrate, and follow any conscious event. The reader’s experience of these words is profoundly shaped by early experiences of learning to read, which also involved moments of focused consciousness. Research on the hippocampus suggests that conscious experiences are quickly converted into widespread synaptic changes in the brain, which serve to frame and contextualize later events. It seems that conscious and unconscious threads interweave without end. In contemporary science updating what we actually know is our responsibility, so that a change in misleading terms would be useful.

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Table 1.0 Misleading and suggested terminology

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Conscious experiences

While conscious experience has been discussed throughout history, the late 19th century saw a rise in physicalistic reductionism, which, in its more extreme forms, declared “consciousness” and kindred terms to be unscientific. In the 1920s B.F. Skinner defined the goal of “radical behaviorism” as the complete elimination of mentalistic concepts from psychology — about two-thirds of English content words. Skinner’s influence dominated well into the 1970s, and during that time it was extremely difficult for scientists to openly study cs cognition, voluntary control, personal identity, and similar questions.

By the 1980s philosoph...