Brain Conversations

For most lay people, consciousness is psychology. It is how we deal with the world. These people would be surprised to learn that for many psychologists and philosophers, consciousness is an epiphenomenon, meaning that it is not real. They would argue that we do experience consciousness but that it is a byproduct of cognitive processes that have already occurred at an unconscious level. In other words, consciousness is just along for the ride. Articles1 in a recent Scientific American Mind present this view.

Although it is true that the vast majority of cognitive processing does occur below the level of consciousness, does that mean that consciousness is irrelevant? The purpose of consciousness has been and continues to be a hotly discussed topic. Baumeister has provided perhaps the most compelling explanations of the purpose of consciousness. He argues that conscious thought is for internal processing that facilitates downstream interaction with the social and cultural environment. Consciousness enables the construction of meaningful, sequential thought. These constructions are found in sentences and narratives, logical reasoning, quantification, causal understanding, and narratives. In short, it accounts for intellectual and social life. It is used for the simulation of events. (See the Healthymemory Blog Post, “Conscious Thought”)

An article2 written for a different purpose provides support for Baumeister’s ideas. This article dealt with awareness. This topic is important in the context of trying to diagnose patients in a vegetative or minimally conscious state. Misdiagnosis rates here can be as high as 40 percent. A neural correlate for consciousness is much needed. For many years theorists thought that the prefrontal cortex was key and that neural thoughts that reached this area emerged from unconscious obscurity into awareness. However, new research supports the notion that consciousness is a conversation rather than a revelation, and that no single brain structure leads the dialogue.

The neuroscientist Simon van Gaal conducts experiments in which he asks participants to push a button every time they see a certain symbol flash on a screen, except when they see a different symbol that means “stop.” On some trials the stop signal is presented below the level of conscious awareness. Although participants do not see the stop signal, they do hesitate to push the button as though some part of the brain perceived the information. Brain activity is recorded during the experiment via functional MRI and electroencephalography (EEG). The unconsciousness inhibitory signal seems to make it all the way up to parts of the prefrontal cortex despite the participants not being consciously aware of the signal.

Another study supports the claim that awareness emerges when information travels back and forth between brain areas rather than from an ascending linear chain. EEG signals were recorded in patients with brain damage as they listened to stimulating tones. All the patients were awake and alert but exhibited different levels of responsiveness. Mathematical models derived from the data suggest that feedback between the frontal cortex and lower-level sensory areas are crucial to producing conscious awareness. Similar results have been obtained with monkeys and healthy human participants.

Although these studies do not prove Baumeister’s notions regarding the role of consciousness, they do seem to provide supportive evidence.

1Nichols, S. (2011). Is Free Will an Illusion? Scientific American Mind, November/December, 18-19.

and

Koch, C. (2011). Probing the Unconscious Mind, Scientific American Mind, November/December,, 20-21.

2Peck, M.E. (2011). A Conversation in the Brain. Scientific American Mind, November/December, 12.

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

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