The Brain The "Router" in Your Head—a Bottleneck of Processing
http://discovermagazine.com/2010/nov/15-the-brain-router-in-our-heads-processing-bottleneck/
Telford speculated, the brain needs time to reset itself after a pulse of thought before it can carry out another one.
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.”
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.
The mental activity that takes place in Step 2 includes some of the most sophisticated forms of thought we are capable of: weighing lots of information, thinking about our short-term and long-term goals, and figuring out how to meet them.
But 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.
Instead of carrying out many steps simultaneously, we have to do them one at a time.
The researchers found that the psychological refractory period stopped this mental clock (pdf). If a task was stuck in a bottleneck, people did not start timing it. 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.
If Dehaene is correct, the brain’s inner traffic jam may actually reflect a cunning evolutionary compromise. We face new and unexpected decisions many times a day. We couldn’t possibly carry a separate network of neurons for every response to every possible situation. But we can learn rules, and we can use those rules to rearrange an all-purpose router.
One of the deepest flaws in our brains, then, might be a by-product of one of its most impressive strengths.
Telford speculated, the brain needs time to reset itself after a pulse of thought before it can carry out another one.
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.”
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.
The mental activity that takes place in Step 2 includes some of the most sophisticated forms of thought we are capable of: weighing lots of information, thinking about our short-term and long-term goals, and figuring out how to meet them.
But 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.
Instead of carrying out many steps simultaneously, we have to do them one at a time.
The researchers found that the psychological refractory period stopped this mental clock (pdf). If a task was stuck in a bottleneck, people did not start timing it. 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.
If Dehaene is correct, the brain’s inner traffic jam may actually reflect a cunning evolutionary compromise. We face new and unexpected decisions many times a day. We couldn’t possibly carry a separate network of neurons for every response to every possible situation. But we can learn rules, and we can use those rules to rearrange an all-purpose router.
One of the deepest flaws in our brains, then, might be a by-product of one of its most impressive strengths.
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