“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,” John Medina offered in a chapter of his excellent Brain Rules book as he shared many wonderful facts as to how brain works and why.
Not quite a decade earlier, Carol S. Dweck, the Lewis and Virginia Eaton Professor of Psychology at Stanford University, had captured another phenomenon in her book, where she asserted: “Mindsets are just beliefs. They’re powerful beliefs, but they’re just something in your mind, and you can change your mind.” This must be what one can have at heart when we exhort to pay attention to relationship between stress, memory and learning.
And yet if there is one common denominator across the entire history of human culture, it is the hunger to understand more, however, Medina writes:
“There is no unique grouping of physiological responses capable of telling a scientist whether you are experiencing stress.”
He continues, this is because:
“An aroused physiological state is characteristic of both stress and pleasure.”
What emerges is at once a celebration of human achievement and a gentle reminder that the study and observation can at times help answer questions originally thought to be unanswerable. 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:
“A measurable physiological response: There must be an aroused physiological response to the stress, and it must be measurable by an outside party.
A desire to avoid the situation: The stressor must be perceived as averse-something that, given the choice, you’d rather not experience.
A loss of control: The person must not feel in control of the stressor. Like a volume knob on some emotional radio, the more the loss of control, the more severe the stress is perceived to be. This element of control and its closely related twin, predictability, lie at the heart of learned helplessness.”
Medina describes fundamental basics as to how we, through our body, emotions and brain functions, respond, he writes:
“You can feel your body responding to stress: Your pulse races, your blood pressure rises, and you feel a massive release of energy. That’s the famous hormone adrenaline at work. This fight-or-flight response is spurred into action by your brain’s hypothalamus, that pea-size organ sitting almost in the middle of your head. When your sensory systems detect stress, the hypothalamus signals your adrenal glands to dump buckets of adrenaline into your bloodstream. There’s a less famous hormone at work, too-also released by the adrenals, and just as powerful as adrenaline. It’s called cortisol. It’s the second wave of our defensive reaction to stressors. In small doses, it wipes out most unpleasant aspects of stress, returning us to normalcy.”
But questions remains, why do our bodies need to go through all this trouble?
“The answer is very simple. Without a flexible, immediately available, highly regulated stress response, we would die.”[…]
“All of its [brain’s] many complexities are built toward a mildly erotic, singularly selfish goal: to live long enough to thrust our genes on to the next generation.”
And yet, being curious, and while modern science has made tremendous strides in illuminating the neuronal infrastructure of the brain, questions remains: What kinds of survival threats did we experience in our evolutionary toddlerhood? And predators would make the top 10 list. Most of the survival issues we faced in our first few million years did not take long to settle. The saber-toothed tiger either ate us or we ran away from it, but the whole thing was usually over in moments. Medina thus explains:
“Consequently, our stress responses were shaped to solve problems that lasted not for years, but for seconds. They were primarily designed to get our muscles moving us as quickly as possible out of harm’s way.”[…]
“These days, our stresses are measured not in moments with mountain lions, but in hours, days, and sometimes months with hectic workplaces, screaming toddlers, and money problems. Pour system is not build for that.”
At the same time, however, the very instruments that get us out the trouble and save our lives, sometimes can hurt us. Medina writes how stress affects memory:
“The hippocampus, that fortress of human memory, is studded with cortisol receptors like cloves in a ham. This makes it very responsive to stress signals.”
To further illustrate, if the stress is not too severe, our brain performs better when it is stressed than when it is not stressed, Medina adds:
“You can solve problems more effectively and you are more likely to retain information.”
Medina adds that there’s an evolutionary reason for this:
“Our survival on the savannah depended upon remembering what was life-threatening and what was not. Ancestors who could commit these experiences to memory (and recall them accurately with equal speed) were more apt to survive than those who couldn’t. Indeed, research shows that memories of stressful experiences are formed almost instantaneously in the human brain, and they can be recalled very quickly during times of crises.”
If the stress is too severe or too prolonged, however, stress begins to harm learning, Medina writes:
“Stressed people don’t do math very well. They don’t process language very efficiently. They have poorer memories, both short and long forms. Stressed people do not generalize or adapt old pieces of information to new scenarios as well as non-stressed individuals. They can’t concentrate. In almost every way it can be tested, chronic stress hurts our ability to learn.”[…]
“One study showed that adults with high levels of stress performed 50 percent worse than adults with low levels of stress on tests of declarative memory (things you can declare) and executive function (the type of thinking that involves problem solving and self control).”[…]
“Stress hormones can disconnect neural networks, the webbing of brain cells that store most precious memories.”[…]
“Stress hormones also can stop the hippocampus [is deeply involved in many aspects of human learning] from giving birth to brand-new baby neurons. Under extreme conditions, stress hormones can even kill hippocampal cells. Quite literally, severe stress can cause brain damage in the very tissues most likely to help you succeed in life.”
Ouch! Quoting again: “Quite literally, severe stress can cause brain damage in the very tissues most likely to help you succeed in life.”