Consciousness

Where is Consciousness?

People have speculated about the location of consciousness throughout history. Some societies believed consciousness resided in the heart, some the stomach, but most have located consciousness in the head. Eastern religions held that consciousness emanated from the “eye” in the forehead, from the sixth chakra, or in the one neural bundle in the brain that is singular rather than duplicated on each side, the pineal gland. René Descartes also believed that the pineal gland was the seat of the soul. Split-brain studies, in which one side of the brain is separated from the other by severing the connecting corpus callosum (an operation done to prevent life-threatening seizures), have shown, however, that consciousness is distributed across the hemispheres. In addition, neuroimaging studies do not point to any particular location as the place from which consciousness derives. It may be, therefore, that consciousness is a process rather than a place. Francis Crick and his colleagues have developed a theory of the process of consciousness that depends on a form of short-term memory and also on a form of serial attentional mechanism. This attentional mechanism helps sets of the relevant neurons to fire in a coherent semi-oscillatory way, at a frequency of about 40–70 Hz, so that a temporary global unity is imposed on neurons in many different parts of the brain.

What is Consciousness?

Behaviorism in the 20th century impeded the study of consciousness because it was considered too subjective to be investigated, a “black box” that could not yield to accurate observation. Cognitive [Page 172]scientists and philosophers in the 1990s challenged the idea that consciousness could not be studied rigorously, and a new science of consciousness was born. In 1994, David Chalmers challenged philosophers, psychologists, neurophysiologists, and anthropologists to study the basic question, What is consciousness? Until that point, most of research on consciousness explored what he called “the easy problems”: that is, the search for the neural correlates of phenomenal consciousness. However, new methodologies and findings in neuroscience and artificial intelligence changed the focus of the problem to what Chalmers called the “hard problem”—that is, to explain how subjective experience arises from the objective activity of brain cells. A series of biennial conferences in Arizona (Consciousness I—Consciousness XI) brought together all of these professions to discuss the hard problems.

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