How many states of consciousness?

Although I have let doctors administer drugs that would alter my consciousness – most notably, nitrous oxide for a wisdom tooth extraction – I have not yet had a compelling reason to let them remove me from consciousness entirely. Which is just as well, since anesthesia has only been around since 1846 (younger than 28 states) and scientists are still learning exactly what it does to us. Most recently, Dr. Jaideep Pandit produced evidence of “dysanesthesia“, a state in which patients seem unaware of the surgery they are undergoing until they are asked to move their finger, and do so.

The discovery of this dysanesthesia state is fascinating, but I do have to object to its characterization in the popular press as “third state of consciousness“. It is a new state of consciousness, to be sure, but why would anyone think that before there had only been two, “unconscious” and “conscious”?

There are so many ways to be unconscious. No anesthesiologist would agree that being under anesthesia is the same as being asleep. Even sleep is not one solitary state of unconsciousness; it contains at least five different stages (including the ever-popular REM sleep), characterized by different patterns of brain activity. Consider the light doze you enter just as you fall asleep, when you can so easily be awakened by your partner climbing into bed or teenager sneaking back into the house; now contrast that with the deep sleep from which you must be shaken to be dragged back to consciousness, and still you emerge unsure of time or place. Although neither of these states feels like “consciousness”, one of them seems closer to it than the other.

There are also many ways to be conscious. There’s the physical present but mentally dazed  state favored by many students at 8 a.m., and the intense focused concentration on one task that will make everything else fade away. There’s the hyper-vigilance characteristic of PTSD, and the extra awareness at the heart of mindfulness practice. And of course there are consciousness altering drugs, like the nitrous oxide I mentioned earlier, the infamous LSD, and the increasingly-legal marijuana.

Current perspectives on consciousness see it not as an all-or-nothing state, but a spectrum. The version I am most familiar with sees consciousness as a combination of two factors: your awareness of yourself and your surroundings, and your ability to generate your own actions (called “level of arousal”). Dysanesthesia would take its place on this spectrum (some awareness, but low arousal) alongside some dozen other states of consciousness.

A multitude of conscious states exist. Image from the Stanford Institute for Neuro-Innovation & Translational Neuroscience.

A multitude of conscious states exist. Image from the Stanford Institute for Neuro-Innovation &
Translational Neuroscience.

One other advantage of this conceptualization of consciousness is that it allows more room for animal or machine consciousness. Consider consciousness as a continuum, and you no longer have to choose between your puppy or IBM’s Watson having complete conscious experiences just like a human being, or being non-conscious entities no more aware than a sea slug. When I consider all our animal companions, in fact, I have to wonder if different states of consciousness number in the hundreds – certainly, fare more than just three.


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