By Ken A. Paller, Northwestern University and Satoru Suzuki, Northwestern University
We have no entirely satisfactory explanation for why a relentless stream of experiences normally fills your mind. On close examination, consciousness can seem truly miraculous and hopelessly ineffable. And, by this way of thinking, scientific research on consciousness would be pointless.
The idea that conscious experiences lie outside the realm of scientific inquiry regularly appears in the press. If the origins of consciousness are supernatural or otherwise beyond human understanding, there’s no hope for addressing the question in a scientific way.
To the contrary, in a new paper published in the journal Trends in Cognitive Sciences and summarised here, we brought together arguments against the position that this fundamental facet of the human mind will forever be beyond human understanding.
Crucial ingredients for awareness
You may think that if you attentively inspect something you must be aware of it. Not true. A few moments experiencing “motion-induced blindness” should convince you. Watch the video below from the website of Michael Bach. Stare at the flashing green light in the middle. The yellow dots may completely vanish from your mind, even though they remain objects of your concentration.
You may think that analysing and making decisions necessitate awareness. But not necessarily. You can have no awareness of a briefly flashed number but still accurately assess its value, perform a mathematical operation, and produce an appropriate answer.
If strong sensory stimulation, attention, and deep analysis do not guarantee awareness, what is the crucial ingredient? One answer is that awareness depends on a reciprocal exchange of information across multiple areas in the cerebral cortex – the large folded sheet of tissue that makes up over 80% of the brain’s mass.
A small region of the cerebral cortex known as primary visual cortex is important for visual awareness. Damage to this area usually results in blindness. Nevertheless, some patients can correctly discriminate moving objects even without consciously seeing them, demonstrating “blindsight”. In these cases, the ability to make judgements about an object without being aware of it presumably reflects restricted cortical processing without the reverberating exchange of information.
Area V5 is a part of the cortex thought to play a major role in perceiving visual motion. Strange motion sensations can be experienced when V5 is artificially activated, but not if communication from V5 to primary visual cortex is disrupted. For motion perception – and perhaps for other conscious experiences – the exchange of information between specific cortical areas seems essential.
A rich conscious experience may also require a complex landscape for the exchange of information. A suitable mixture of short, medium and long-range neuronal connections may be needed. Such a mixture indeed characterises the anatomy of the cerebral cortex.
Understanding consciousness
You may think that human consciousness is too fantastic for us to ever comprehend. However, this view may be based on commonly held but incorrect assumptions about your own introspections.
With some effort, we can recognise the shortcomings of these assumptions. Then we can use scientific methods to develop an integrative understanding of the mind and its origin, evolution, development, and subjectivity.
A rational worldview cannot disregard the fact that people have subjective experiences. Even science relies on conscious perception and reasoning. Therefore, the topic of human consciousness belongs within the purview of science, despite philosophical or religious arguments to the contrary.
A wide range of scientific perspectives can offer useful clues about consciousness. Although conscious experiences are inherently private, scientists are making progress on developing new objective measures based on brain physiology. Measures of information exchange in the brain represent a promising avenue. These efforts are bringing us closer to testing specific hypotheses about consciousness.
The necessary reliance on subjective reports requires great care, but increasing the validity of these reports is possible. We can experimentally constrain subjective choices, sharpen introspective abilities with meditation training, and steadily advance our understanding of the neural mechanisms of conscious experience.
There is thus ample reason to be optimistic about future scientific inquiries into consciousness. These efforts could lead to many benefits for society. For example, continuing efforts to characterise types of neural interaction that are essential for consciousness could help us adjudicate difficult decisions involving human and animal rights, support efforts to diagnose and treat diseases that impinge on consciousness, and foster environments and technologies that contribute to the wellbeing of individuals and society.
Science can make consciousness more understandable. And there’s so much more to learn. And as this research continues, revealing more and more, consciousness continues to be utterly amazing.
The authors do not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article. They also have no relevant affiliations.
This article was originally published on The Conversation.
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