Two Facts Collide in the Brain

I recently heard a developmental molecular biologist address us teachers about research on the human brain and its possible implications for how we teach our students.  He is an animated speaker whose own brain runs at warp speed, and I learned a number of fascinating things from him.  Here and now, though, I will focus on one of them: 300 milliseconds.

200-300 milliseconds (1/5 to 1/3 of a second), apparently, is the minimum time it takes the executive center of the human

This is your brain on colored dye, with credit to Gutenberg Encyclopedia.

brain (which processes requests one at a time) to change from one simple, conscious task to another.  Again, that's only for simple tasks, whatever those are.  Complex ones can take much longer to begin.  That's not even the time it takes me to think about something.  That's the minimum time it takes me to start consciously thinking about anything.

I suppose we all come to the same facts from varying perspectives.  Perhaps 300 milliseconds doesn't seem like very much time.  After all, it may be faster than the blink of an eye, which clocks in at 300 to 400ms.

Personally, that 300 ms changes the way I see myself as a human being.  I am monumentally slower than I want to think I am.

Let me share a different perspective.  I develop computer code that is shooting Latin sentences from students in places as remote as New Zealand or Tel Aviv to a high-powered server in Dallas, doing all kinds of conditional logic and data gymnastics, and sending them back again.  I've now invested years of my life in that action-packed round trip, which involves a relay of code in several different computer languages.

Today, from my desk in Tennessee, that entire process takes about 93 milliseconds.  It will go to Dallas, do its thing, and shoot everything back here before I can even start to think about opening Facebook.

My friend and mentor Scott Salisbury, whose company develops such solutions for corporate clients,

photo credit: Hustvedt

assures me that this figure is basically all server time.  After all, signals traverse fiber-optic cable at the speed of light, which would take me from here to Dallas in less than 4 ms!

There are times when speed matters, too.  300ms seems like a very long time for my brain to switch from engaging in a cell phone conversation to considering whether... perhaps... I should slam on the brakes.  And to go back from driving to the phone conversation?  Another 300ms.  And each time my brain switches, the car I used to drive is carrying my body another 31 feet while my mind is somewhere else. Yes, my eyes have never left the road.  My hands may still be on the wheel.  The lights are on, but I'm just not quite home at the moment.

Iraqi children - photo credit: Christiaan Briggs

We all still want to believe that we really can truly, meaningfully multitask.  We believe we experience it every day.  We insist that we can prove it.  We've raised multiple kids, for crying out loud!  What about a guitarist riffing his scales at 120 beats per minute while watching football on TV?  Heck, that guy even looks bored!  Apparently many things get chunked together and/or delegated to muscle memory.  That's what practice does.  But the chunks of conscious thought - however elaborate - still pass through the executive center of the brain, one at a time.

Even more importantly, how much additional "server time" does my brain spend actually listening to the other person instead of driving?  How much time is spent processing emotions?  How much time does it spend composing a response? After all, if - as we were repeatedly assured - all executive processing is sequential, 300ms is only the transition time, not the total time off task.  It's just a drop in the bucket of things I am not noticing.

Even with the best of intentions, I've seen students run into a similar problem: they think they can complete another task on their devices and still be listening in class.  They really believe they are listening too, but when I talk to them, they aren't "there."

300ms humbles me. Like the drunk guy who wants the keys, I may not be in the best position to judge objectively my own limits, because there is a lot of life going on while I am neurologically unable to pay attention.  But I still think I can!  So, if you call me while I'm driving, my phone probably will ring...inside my glove box, where I cannot reach it.