How to Measure Consciousness: A neuroscientist seeks to quantify our awareness according to a new metric- phi
Human consciousness is a mystery that has occupied great thinkers for centuries, from philosophers who have puzzled over the nature of the mind to biologists trying to figure out how a network of neurons can work together to create self-awareness. On one hand, consciousness is a basic trait we all have in common; but, on the other, it’s abstract, transparent, undefinable, and—worst of all, from a scientific point of view—unquantifiable. That makes it very hard to study.
Now that may be changing. Over the last few years, Giulio Tononi, an eminent neurobiologist at the University of Wisconsin, has been working on a way to quantify consciousness. He argues that it’s possible to define consciousness mathematically. More than that, he says, it’s possible to measure it. Measuring consciousness—assigning a number to your current state of awareness—might sound impossible. But, using a combination of information theory and neuroscience, Tononi has come up with a plausible way to gauge how much consciousness is unfolding inside a brain at any given time. He’s already taken some rough measurements of people who are awake, sleeping, and even in vegetative or “locked-in” states.
His work is based on a potentially revolutionary theory about how consciousness works. Tononi argues that consciousness is made of what he calls “integrated information”—information that happens to be stored in our neurons, but that could, in principle, be stored in many different media. The information is “integrated” because of the complex, hierarchical way in which it’s organized: Smaller systems integrate elegantly into bigger and bigger ones, combining their information to create something that’s more than the sum of its parts. The human brain, Tononi says, is unequalled in its ability to organize its information in a meaningfully integrated way. And it’s possible to measure the degree of integration, he argues, by using a web of electrodes to measure how a brain reacts to an external stimulus, like a magnetic pulse.