•
The neurons of your brain show vigorous rhythmical activity when
you’re asleep—perhaps replaying what you learned that day.
•
People vary in how much sleep they need and when they prefer to get it,
but the biological drive for an afternoon nap is universal.
•
Loss of sleep hurts attention, executive function,
working memory,
mood, quantitative skills, logical reasoning, and even motor dexterity.
IT IS, BY ANY measure, a thoroughly rotten experiment. Here is this
beautiful German shepherd, lying
in one corner of a metal box,
whimpering. He is receiving painful electric shocks, stimuli that should
leave him howling in pain. Oddly enough, the dog could easily get out. The
other side of the box is perfectly insulated from shocks, and only a low
barrier separates the two sides. Though the dog could jump over to safety
when the whim strikes him, the whim doesn’t strike him. He just lies down
in the corner of the electric side, whimpering with each jarring jolt. He must
be physically removed by the experimenter to be relieved of the experience.
What has happened to that dog?
A few days before entering the box,
the animal was strapped to a
restraining harness rigged with electric wires, inescapably receiving the
same painful shock day and night. And at first he didn’t just stand there
taking it, he
reacted
. He howled in pain. He urinated. He strained mightily
against his harness in an increasingly desperate attempt to link some
behavior of his with the cessation of the pain. But it was no use. As the
hours
and even days ticked by, his resistance eventually subsided. Why?
The dog began to receive a very clear message: The pain was not going to
stop; the shocks were going to be forever.
There was no way out.
Even after
the dog had been released from the harness and placed into the metal box
with the escape route, he could no longer understand his options. Learning
had been shut down.
Those of you familiar with psychology already know I am describing a
famous set of experiments begun in the late 1960s by legendary
psychologist Martin Seligman. He coined the term “learned helplessness” to
describe both the perception of inescapability and its associated cognitive
collapse. Many animals behave in a similar fashion when punishment is
unavoidable, and that includes humans. Inmates in concentration camps
routinely experienced these symptoms in response to their horrid
conditions.
Some camps gave it the name
Gammel
, derived from the
colloquial German word
Gammeln
, which literally means “rotting.” Perhaps
not surprisingly, Seligman spent the rest of his career studying how humans
respond to optimism.
What is so awful about severe, chronic stress that it can cause
behavioral changes as devastating as learned helplessness? Why is learning
so radically altered? We’ll begin
with a definition of stress, talk about
biological responses, and then move to the relationship between stress and
learning. Along the way, we will talk about marriage and parenting, about
the workplace, and about the first and only time I ever heard my mother, a
fourth-grade teacher, swear. It was her first real encounter with learned
helplessness.
What is stress? It depends
Not all stress is the same. Certain types of stress really hurt learning, but
some types of stress
boost
learning. Second, it’s
difficult to detect when
someone is experiencing stress. Some people love skydiving for recreation;
it’s others’ worst nightmare. Is jumping out of an airplane inherently
stressful? The answer is no, and that highlights the subjective nature of
stress.
The body alone isn’t of much help in providing a definition, either.
There is no unique grouping of physiological responses capable of telling a
scientist whether you are experiencing stress. That’s because many of the
mechanisms that cause you to shrink in horror from a predator are the same
mechanisms used when you are having sex—or even while you are
consuming your Thanksgiving dinner.
To your body, saber-toothed tigers
and orgasms and turkey gravy look remarkably similar. An aroused
physiological state is characteristic of both stress and pleasure.
So what’s a scientist to do? A few years ago, gifted researchers Jeansok
Kim and David Diamond came up with a three-part definition that covers
many of the bases. In their view, if all three are happening simultaneously, a
person is stressed.
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