If you cut off your thumb, you would (likely) still be conscious. If you cut off a thumb-sized part of your brainstem, however, you would almost certainly be down for the count.
The idea that consciousness is supported by a physical organ — the brain — isn’t radical. Networks of neurons in our brains enable various conscious states, from sleep, to awareness, and everything in between. And yet, you’ll be hard-pressed to find research labs that are trying to understand how the computations in neural circuits support different conscious states and the shifts between them.
This is the case even though a deeper understanding of the neural basis of consciousness has far-reaching ethical implications, from how we treat individuals on life support, to whether a robot could ever truly be conscious. That’s why we need to start treating consciousness as a rigorous scientific discipline.
We in neuroscience don’t avoid doing so out of a lack of interest — many researchers were originally drawn to our field by questions about consciousness, and philosophers have long wondered about the biological correlates of consciousness. Contemporary philosophers such as Patricia Churchland will tell you that consciousness is simply another function enabled by neural circuits. Others, like David Chalmers, contend that consciousness is a fundamental property of neural networks, just like gravity is a fundamental property of matter.
We could take such theories and ask if they hold any water in real neural circuits while observing real behaviors in the same way that neuroscientists investigate circuits in other brain systems, such as for visual processing or value judgements. In fact, philosophers like Chalmers have called for a proper science of consciousness.
Although there are claims that consciousness is a “buzzing business in neuroscience labs,” it’s uncommon in labs that study the brain on the level of single neurons and neural circuits. You’ll find some computational and human research groups working on the science of consciousness, but it’s not mainstream neuroscience. For some reason, most neuroscientists don’t want to touch it. And it’s not because we don’t have the tools to do so. The most significant hurdle to the rigorous study of consciousness is overcoming its reputation as an unviable research topic.
Building a study of consciousness
In order to bridge theories of consciousness with detailed, mechanistic understandings of brain function, we need a clear definition of conscious states, a way to measure these states both behaviorally and biologically, and conceptual frameworks to consider our findings.
Given the ethical considerations of characterizing patients’ consciousness, there are existing medical guidelines for doctors to describe conscious states of patients. Psychologists have spent the past century dividing personality in multiple dimensions, and I’m confident that consciousness can be operationalized in similar ways in both humans and animals. Neuroscientists are constantly trying to map behaviors such as attention onto animal models, and we could do the same with conscious states.
To study consciousness like we study other phenomena, we also need to be able to control the degrees of consciousness. Shifting subjects between conscious and unconscious states might be ethically and technically tricky, but it’s feasible (and really, we already manipulate our consciousness with anesthesia and mind-altering drugs).
We also already have compelling computational models of how the communication between neurons might enable conscious states. One researcher, Guilio Tononi, is one of the few people who has made a career out of consciousness research. His theoretical framework, Integrated Information Theory (IIT), argues that the amount of consciousness in a neural circuit is determined by how much information can be integrated in the connections within that circuit. IIT implies that different species can have varying amounts of consciousness, a view termed “panpsychism.” It also accounts for phenomena such as the loss of consciousness during generalized seizures, but it hasn’t been tested in living neural circuits.
Lastly, there isn’t a technological constraint for consciousness research in neuroscience. Neuroscientists love technology, and many researchers are dedicated to developing ever more precise ways to manipulate and record from the brain. Given the remarkable technology that neuroscientists now have access to, we could begin to understand how neural circuits enable consciousness.
Applying innovative tools to an old, complicated problem
The problem is that many neuroscientists are unwilling to apply cutting-edge techniques to questions in the realms of philosophy and psychology. They’ll say, “we already indirectly study consciousness” or “it’s not something we can test experimentally, so it’s not worth it.” Somehow, consciousness is both incredibly mundane and overwhelmingly indefinable.
Consciousness is something we all experience, and it’s likely buried in all of the phenomena we already study, such as visual processing and decision-making. Others will argue that consciousness has an ineffable, non-scientific, squishyness. Perhaps parts of it - the truly subjective parts, like if red looks different to different people - are not possible to study in a scientific context, but many aspects of it are.
Still, at most research institutions, proposing to study consciousness is akin to declaring you’re no longer a serious scientist. Some neuroscientists drop the C-word every now and then, but it’s really only something a secure, tenured professor can discuss (and even then, many people will find it eye roll inducing).
I’m not a consciousness studies eye-roller, despite spending the past seven years in a subfield that is extremely critical of biological explanations for cognitive concepts such as attention, decision-making, or consciousness. Although this level of skepticism is warranted, my immediate response isn’t to assume it’s all far-fetched hogwash, like many of my colleagues do. Don’t get me wrong — I am a Loyal Disciple of The Scientific Method — but I’m also a firm believer in the ability of seemingly outlandish ideas to transform a discipline. I have tremendous respect for researchers who are willing to put themselves on the line and push the envelope on topics most of us are too nervous to tackle.
As neuroscientists, we need to be willing to develop imperfect algorithmic descriptions of difficult cognitive phenomena. Thoughtful wrestling matches with tough cognitive and philosophical concepts deserve the same intellectual attention as our seemingly endless obsession with improving methodologies.
Not all research topics are equally sexy and fundable – for good reason. We’re careful with our money. But the fear of rubbing up against squishy philosophical topics also keeps topics such as consciousness in the fringe category, perhaps more so than it deserves.