What is consciousness? Study aims to settle debate

In science, plenty of problems are hard. But perhaps just one is so gruesomely trying that scientists themselves have termed it, well, “the hard problem.” How does consciousness arise -- the living, aware experience of being?

Some theories hold that it comes from, or is even identical to, electrical and chemical processes known to unfold in the brain. Others say it arises elsewhere: in some even subtler, yet undiscovered brain processes, or perhaps a mind-stuff quite distinct from the brain -- some call it a soul.

Few on either side claim to have final answers. But they often argue passionately over who’s at least in the right playing field.

Now a group of re searchers has begun a study that they say might settle the issue. “We can actually test this, and put and end to all these debates,” said Sam Parnia, a critical care doctor at Weill Cornell Medical Center in New York.

Parnia has spent years studying reports that some cardiac arrest patients keep having clear, distinct thought processes after they’re clinically dead and detect able brain activity has ceased. Patients commonly recount these mental experiences, which of ten include seeing a light at the end of a tunnel, after being revived.

Parnia and colleagues aim to put these reports to a test: specific sounds will be played to such patients, and they’ll be asked to recall the sounds af ter reviving. If they do, it would confirm the accounts of thoughts with out brain activity -- supporting the claims that “consciousness is a separate, yet undiscovered scientific entity” from the brain, Parnia wrote in a paper in the the April 23 advance on line edition of the research journal Medical Hypotheses.

The study “looks like an interesting proposal,” wrote David Chalmers, a philosopher and director of the Centre for Consciousness at the Australian National Univers ity in Canberra, Australia, in an e-mail. If the claims are confirmed, it would “pose an interesting challenge for scientists to explain,” remarked Chalmers, author of several books on consciousness.

But it probably wouldn’t settle the most basic, long standing dispute: whether mind and brain are different things, Chalmers added. For instance, even if patients’ claims are verified, they “could be due to as pects of brain functioning during cardiacarrest that are not captured by the measurements” Parnia is using, Chalmers wrote. These measurements are taken by electroencephalogram, a technique in which sensitive electrodes attached to the head record electrical brain activity.

Parnia said the trials began on a pilot basis in January at two U.K. hospitals with 10 patients; he aims to expand the study to other countries and recruit over 1,000 pa tients.

Perhaps the most stringent test in the study is also the one that addresses the most extra ordinary notion. Critically ill patients sometimes report “out-of-body” experiences in which they feel they have floated out of their own bodies and are watching themselves from above.

Mark well: Parnia is not testing whether patients genuinely feel their minds have floated away. He wants to test whether the minds actually do float away -- a controversial idea to say the least. His team plans to place pictures strategically around patients’ rooms where they’re visible only from near the ceiling. Patients would later be asked about the images. “Thus, the claims of conscious awareness and out-of-body experiences will be tested independently,” he wrote in the paper.

He admitted some would find the idea outlandish. A study published in 2002 found that just electrically stimulating specific brain areas could trigger an out-of-body-like experience -- evidence to some that the sensations are illusory.

Daniel Dennett, director of the Center for Cognitive Studies at Tufts University in Medord, Mass., wrote in an e-mail that he’s never seen evidence that the events are anything more than hallucinations. The experiments, “if conducted with scrupulous care,” will surely confirm this, added Dennett, a philosopher who is also author of sever al books on consciousness.

Yet, said Parnia -- in defense of the oppo site view -- patients have accurately reported events in their hospital rooms that occurred during out-of-body experiences, while they were clinically dead. “If we get 200 people, and all claim to have an out-of-body experience but none can identify the images, that would very much support the idea that this is a false memory,” Par ia said. “If on the other hand, 200 people identify these im ages… then we’d have to accept that may be human consciousness, as bizarre as it may sound, could be non-local to the brain.”

World Science