Today's Carl Zimmer article gives new insight into the nature of consciousness. Even in neurotypical brains decision tasks create a psychic bottleneck, which is also a sort of perceptual blindspot. Our consciousness goes "offline", very briefly, when we make choices (emphases mine) ...
The Brain: The "Router" in Your Head—a Bottleneck of Processing | Carl Zimmer | DISCOVER Magazine:
... The brain is, in the words of neuroscientist Floyd Bloom, “the most complex [jg: known] structure that exists in the universe.” Its trillions of connections let it carry out all sorts of sophisticated computations in very little time. You can scan a crowded lobby and pick out a familiar face in a fraction of a second, a task that pushes even today’s best computers to their limit. Yet multiplying 357 by 289, a task that demands a puny amount of processing, leaves most of us struggling.
... The fact that we struggle with certain simple tasks speaks volumes about how we are wired. It turns out the evolution of our complex brain has come at a price: Sometimes we end up with a mental traffic jam in there...
... If we don’t have enough time between two tasks, we slow down on the second one—a lag known as the “psychological refractory period.”...
... Psychologists have long been puzzled by the psychological refractory period because it doesn’t fit with other things we know about how the brain works. We are very good at doing many things at once... Yet there are simple jobs—like math problems—that our brains can handle only one at a time. It is as if signals were flying down a 20-lane superhighway, and then the road narrowed to a single lane...
Each time we perform a task we perform it in three steps. Step 1: Take in information from the senses. Step 2: Figure out what to do in response. Step 3: Carry out that plan by moving muscles...
... scientists varied one of the three steps of the thought process to see if they could change the length of the psychological refractory period. Only when they tinkered with step 2—figuring out what response to make—could they produce a change...
... when we have any two simple decisions to make, we must wait for the first task to move through a bottleneck before taking on the second. That is what makes mental multiplication so hard. Instead of carrying out many steps simultaneously, we have to do them one at a time.
... In 2008 the scientists reported that during the psychological refractory period, a network of brain regions are consistently active, some near the front of the brain and some near the back...
... these regions appear to be part of a network that is important for our awareness of our own experiences. This helps explain why we are oblivious to our mental traffic jams.
.. The brain began measuring how long a task took only after the previous task moved out of the bottleneck. Whenever a perception of a sound or a letter got stuck in the mental traffic jam, the subjects were not aware of it...
... The neurons that take in sensory information send it to a neural network that he and his colleagues call the "router." Like the router in a computer network, the brain’s version can be reconfigured to send signals to different locations. Depending on the task at hand, it can direct signals to the parts of the brain that produce speech, for instance, or to the parts that can make a foot push down on a brake pedal. Each time the router switches to a new configuration, however, it experiences a slight delay...
The "router" theory is very much an unproven model. If something like it holds up, however, we will find variations in router performance. There may be advantages and costs to different router algorithms. There will be articles on router performance in autism and schizophrenia and in disorders of consciousness (coma, etc). Perhaps we will discover ways to train and retrain our internal routers for different settings.
It wasn't the primary emphasis of the article, but I'm struck again by the contingent and intermittent nature of our consciousness. Continuity of consciousness is very much an illusion. We are offline, briefly, thousands of times a day.
