Can unconscious brains think? Coma, philosophy of mind, and the media.

“Ok brain. I don’t like you and you don’t like me. Let’s just do this and I can go back to killing you with beer.”  - Homer Simpson

A new piece of research has elicited headlines around the world in today’s newspapers such as “Coma patient ‘talks’ with his thoughts” and “Coma victim talks via brain scanner“. These articles tell us that researchers have “unlocked” some coma patients’ minds and have proven that they are conscious but unable to move or communicate in normal ways.

It’s a terrifying idea.

But outside of the mainstream media, some scientists and other researchers are sceptical of these sensational claims. Ken Weiss, professor anthropology and genetics and Penn State University, argues on his group blog “The Mermaid’s Tale” that we should be cautious of attributing “consciousness” to these patients since unconscious parts of brains can respond to stimulus.

Many experiments on humans who have had surgery that impaired one of their hemispheres, or separated their two hemispheres, have shown that rational, responsive, decision-making capability exists independent of consciousness. Other recent work shows that conscious awareness may monitor, but comes split seconds after decisions are made by the brain. In other words, brains can think without being conscious.

Obviously, such claims depend on what we mean by “consciousness”. For example, if you think consciousness is the ability to demonstrate “rational, responsive, decision-making capability” then it makes no sense to claim that unconscious brains can do that. Such a brain is, by definition, conscious.

But presumably we mean something a little more by “consciousness”. Presumably we require some degree of “self-reflection” for something to count as conscious — some degree of awareness of the self.

So, are the patients in the new study conscious? To answer this, we don’t need to get bogged down in confusing (and confused) philosophical discussions about what consciousness is. This is obviously the case if you consider more everyday examples: I don’t need to know what consciousness is to decide whether or not you are conscious. I decide that just by talking to you. In a sense, we’re all experts at making such decisions.

Similarly, we should be able to decide whether or not (or to what degree) the coma patients are conscious without getting bogged down in definitional questions. If these patients can express desires and beliefs then there can be little doubt that they are conscious.

Ken asks his readers the following question:

For example, suppose it could be shown that these unfortunate people are not conscious, but that their unconscious brains are functioning. Should we ask those partially aware brains if they want to live or die?

If these patients are functioning to such a degree that we can ask them whether they have a desire to live or to die, then it makes little sense to conclude that they are still unconscious. The fact that they have their eyes closed and cannot move does not change matters: if they can behave as though they are conscious, then they are.

The idea that we could “talk” to a patient’s mind, but not to them is a rather ridiculous idea. The sillyness of the idea is what makes the above quote by Homer Simpson funny – you can’t talk to your mind because you are your mind!

In the particular study in question, there can be little doubt that the patients (particularly one of them) who have been diagnosed as being in Vegetative State have some significant degree of consciousness. One of these patients could understand a task described to them, and answer several questions about his life correctly. As Vaughan at Mindhacks said,

Out of these six simple questions, the patient ‘responded’ correctly to 5, suggesting that they were genuinely understanding, considering and making a conscious response. This was in a patient who had no external signs of consciousness. (My italics.)

ResearchBlogging.org

Monti MM, Vanhaudenhuyse A, Coleman MR, Boly M, Pickard JD, Tshibanda L, Owen AM, & Laureys S (2010). Willful Modulation of Brain Activity in Disorders of Consciousness. The New England journal of medicine PMID: 20130250

Martin M. Monti, & Audrey Vanhaudenhuyse (2010). Willful Modulation of Brain Activity in Disorders of Consciousness The New England Journal of Medicine : 10.1056/NEJMoa0905370