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The Priming Effect

Inside your skull is a massive supercomputer. You own it free and clear. With its 100 billion neurons, and with a typical neuron linking to 1000 to 10,000 other neurons, your highly networked brain is incredibly powerful and capable.

Pick up a simple object nearby like a pen or a spoon, and look at it. Turn it upside down. Spin it around. Notice that your brain is able to recognize the object no matter how you position it. You can change the lighting by putting the object in shadow. You can obscure part of it from view. You can bend or break it. And your brain still recognizes that object simply and easily. Even a child can do this.

But what’s happening under the hood? Your visual cortex, consisting of about 538 million neurons, is doing an enormous amount of parallel processing on the signals it’s receiving from your eyes. Your visual cortex detects edges, evaluates color, tracks motion, interprets reflection, and more — all in real time.

Your brain even does some extra processing to compensate for the blind spot on the back of your retina. Your eyes don’t actually “see” any data for that blind spot because there are no rods or cones there — it’s the place where your optic nerve connects to the back of your eyeball — but your visual cortex uses the surrounding information to intelligently predict what should be in that blind spot, and it fills in the missing data with its best guess. If a line crosses through your blind spot, you’ll still perceive it as a continuous line, even though the initial data coming from your retina has that line broken into two pieces.

All of this processing happens subconsciously. You don’t feel it happening, and you aren’t consciously aware of all this computational effort. Yet that part of your brain is very active, lit up with chemical and electrical activity, consuming oxygen and sugar and other internal resources to perform such complex computations at such high speed.

Even when you focus your attention upon it, you can’t consciously access what your visual cortex is doing. These computations are way too fast and way too complex for your conscious mind to keep up.

Your visual cortex is only about 1/200th of your brain. Your auditory cortex is about 1/1000th. If you can’t even consciously fathom what these relatively small brain regions are doing computationally, what hope do you have of maintaining awareness of what the rest of your brain is doing on an ongoing basis?

The truth is that this is a hopeless challenge. Your conscious mind doesn’t have anywhere close to the capacity that would be required to intelligently monitor and maintain all the thoughts, feelings, and beliefs that are constantly firing inside of you. Most of the time you’re not even aware of what’s happening inside your mind.

You may perceive the experience of thinking as a fairly linear process. Your conscious mind seems to flow through basically one thought at a time, just as you may read one word at a time. But that isn’t what’s actually happening behind the scenes.

The reality is that different patches of neurons are processing different thoughts in parallel at all times. Your thinking is never linear and straightforward. Even when you read words in a linear order, your brain is actually perceiving and processing all of the words within your field of view at all times.

When you listen to human speech, your brain is automatically predicting which words are likely to be heard next. It’s actually pre-loading multiple patterns simultaneously. Then when the next word is verified, your brain fires off different neuron patches to suppress the incorrect predictions and to validate the correct branch. Your brain doesn’t actually wait for words to be spoken. It processes syntax and meaning well ahead of what it’s hearing. And since it can’t predict every word with perfect accuracy, it predicts along multiple branches at the same time.

Even if I leave a few words out of this ____, your ___ can still read the sentence just fine. It picks up the meaning. If I said this sentence aloud and paused briefly at the blanks, you may have even experienced the phantom audio effect of hearing the words that weren’t actually spoken.

What were the fill in the blank words? Were they sentence and brain? Statement and mind? Line and eyes. It doesn’t matter. Your brain simultaneously explored multiple possibilities and filled in the expected meaning.

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