Thinking about one
memory tends to activate other memories. This can be both an advantage and a
disadvantage. If you are trying to
retrieve a particular memory, the flood of activations can cause competition
among different nodes, leaving you with a traffic jam of neural nodes trying to
get through to consciousness.
The processing
capacity of the conscious mind has been estimated at 120 bits per second. That bandwidth, or window, is the speed limit
for the traffic of information we can pay conscious attention to any one time….
In order to understand one person speaking to us, we need to process 60 bits of
information per second. With a
processing limit of 120 bits per second, this means you can barely understand
two people talking to you at the same time.
The Sumerian city of
Uruk (~5000 BCE) was one of the world's earliest large cities. Its active commercial trade created an
unprecedented volume of business transactions, and Sumerian merchants required
an accounting system for keeping track of the day's inventory and receipts;
this was the birth of writing.
Neuroscientists are
increasingly appreciating that consciousness is not an all-or-nothing state;
rather, it is a continuum of different states.
When we have
something on our minds that is important -- especially a To Do item -- we're
afraid we'll forget it, so our brain rehearses it, tossing it around and around
in circles in something that cognitive psychologists actually refer to as the
rehearsal loop…. Writing them down gives both implicit and explicit permission
to the rehearsal loop to let them go, to relax its natural circuits so that we
can focus on something else.
Some foods that we
consider haute cuisine today, such as lobster, were so plentiful in the 1800s
that they were fed to prisoners and orphans, and ground up into fertilizer;
servants requested written assurance that they would not be fed lobster more
than twice a week.
Three out of four
Americans report that their garages are too full to put a car into them. Women's cortisol levels (the stress hormone)
spike when confronted with such clutter (men's, not so much). Elevated cortisol levels can lead to chronic
cognitive impairment, fatigue, and suppression of the body's immune system.
The neurologist and
writer Oliver Sacks goes one further: if you're working on two completely
separate projects, dedicate one desk or table or section of the house for
each. Just stepping into a different
space hits the reset button on your brain and allows for more productive and
creative thinking.
Being in a situation
where you are trying to concentrate on a task, and an e-mail is sitting unread
in your inbox, can reduce your effective IQ by 10 points.
It turns out that
decision-making is also very hard on your neural resources and that little
decisions appear to take up as much energy as big ones. One of the first things we lose is impulse
control.
You receive a text,
and that activates your novelty centers.
You respond and feel rewarded for having completed a task (even though
that task was entirely unknown to you fifteen seconds earlier). Each of those delivers a shot of dopamine.
Notions of privacy
that we take for granted today were very different just two hundred years ago.
It was common practice to share rooms and even beds at roadside inns well into
the nineteenth century. Diaries tell of
guests complaining about late-arriving guests who climbed into bed with them in
the middle of the night.
The act of living in
cities and towns together is fundamentally an act of cooperation.
The natural
intuitive see-saw between focusing and daydreaming helps to recalibrate and
restore the brain. Multitasking does
not.
That
middle-of-the-night waking might have evolved to help ward off nocturnal
predators.
Two faulty beliefs:
first, that life should be easy, and second, that our self-worth is dependent
on our success.
During flow [state],
two key regions of the brain deactivate: the portion of the prefrontal cortex
responsible for self-criticism, and the amygdala, the brain's fear center.
