Stress: A Teacher’s Enemy or Ally?

Stress: A Teacher’s Enemy or Ally?

By: Curtis Kelly

Among the Best of 2021

Readers chose this article as one of the seven best from all of 2021! Check out the other nominees with the button below.

 “The greatest weapon against stress is our ability to choose one thought over another.”     – William James

Stress. The Problem Child of life sciences.[1] Good or bad? Enemy or ally? For example, dozens of teachers I’ve met at conferences have said: “A little stress helps learning.” Thousands of websites: “Stress is a killer.” A century of research: Well, hard to summarize, but look at what Newsweek’s Mary Carmichael had to say:

When I started asking researchers about “good stress,” many of them said it essentially didn’t exist. “We never tell people stress is good for them,” one said. Another allowed that it might be, but only in small ways, in the short term, in rats” (2009, p. 1).

[1] Even defining stress has led to 70 years of controversy. Selye in 1950, defined a stressor as any stimulus that upsets homeostasis, and stress response as effort to restore that homeostasis (Koolhaas et al., 2011, p. 1292). However, since organisms are constantly engaged in maintaining homeostasis in one way or another, this definition is “almost meaningless.” Other ways of defining stress have to do with stress response, whether the organism can adapt to the stressor or not, and, in medical fields, as synonymous with distress. At a recent conference, Modupe Akinola defined stress as when the “demands of a situation exceed your resources.” That is good, but for our purposes, a definition based on the physiological response, cortisol release, is better suited.


So, is it good? Bad? Both? I suspect you are already making the distinction between short-term stress as beneficial and long-term stress as harmful, which is right, but let’s leave long-term stress (“the killer”) out of the question. It should be considered a separate disease, one that harms body function and alters the pre-frontal cortex (Arnsten, 2016). Instead, let’s look at whether a single stress event in a class facilitates learning or hinders it.

I mean, shouldn’t it be one or the other? And, believe me, there is a lot of research that points in both directions.

Fortunately, we can ameliorate this contradiction by focusing on how strong that single stress is. As this chart shows, at least for rats, if the level of stress is low, it aids learning. If it is high, it hinders it (Pietrangelo, 2020).[2]

[2] It delights me to no end that this notion, and the related research on rats that Yerkes and Dodson did in 1908, gave birth to their ubiquitous curve, so often used in other areas of science.

How this relates to stress in the classroom

That makes sense, and yet, this notion in itself is not very useful to us as teachers, because it tells us neither what stress is, nor how to measure its intensity. Yerkes and Dodson could do so by measuring the voltage of the electrical shocks they gave but, in measuring test anxiety, would increasing the number of test items from 20 to 30 work the same way? Probably not, the main reason being that different people react to the same stressor in different ways (Levine & Ursin, 1991), as do rats, in fact.

For example, asking students to tell the class about their summer vacations might delight some learners, and strike dread into others. The same applies to other everyday classroom acts like “find a partner,” “show me your homework,” “let’s play a game,” and “Mei, what is the answer to #4.” Indeed, our classes are full of stress events that hit our students from so many sides: language proficiency, social relations, and self-esteem. And let’s not deny that we exploit it. Is there a teacher anywhere who does not chide, scold, or even rage at students from time to time? Where I teach, in a Japanese university, I know of teachers—some highly respected by the students—who do so daily. And more than once I’ve heard: “My students don’t pay attention unless I yell at them.” In cases like this, stress is being used for behavior modification rather than learning, but, as we shall see, it still has an impact on learning. And again, for each of these examples, there are some students who will not feel any nervous energy either way, some who will be excited, and some who will freeze in the headlights.

In case you are not convinced that seemingly minor acts (like those at the at the start of the previous paragraph) affect stress levels, consider an experiment Reeve and Tseng did (2011). They gave college students a puzzle-solving activity with recorded instructions that used a motivating style that was: 1) controlling, 2) neutral, or 3) autonomy-supportive. Compared to the neutral style, salivary cortisol levels were increased by the teacher-centered controlling style and reduced by the learner-centered supportive style, and in case you didn’t catch it, these were just recorded instructions!

"Stress pervades teaching in obvious and not-so-obvious ways. "
Curtis Kelly
TT Author

Let’s stop here a moment to recap. Here are the main points from the literature:

– Stress can be seen as good (eustress) or bad (distress), and its impact on learning follows a U-shaped curve.

– Different people react in different ways to the same stressor, determined, to some degree, by how they perceive it.

– Stress pervades teaching in obvious and not-so-obvious ways, used both to engender learning and to modify behavior.

There is more

And yet, for me, these conclusions alone are not very satisfying. I do not think they really answer the question of how stress affects learning. Adding salt to a dish makes it saltier, whether a little or a lot, so how can a little or a lot of cortisol release (the best way to define stress) have completely opposite effects on learning, as increasing or decreasing it. To find out, and truly answer the question of whether stress aids or hinders learning, I spent four months of a research leave reading deeply on this topic. And what I found was astonishing: Yes, stress both aids and hinders learning, but not in the way we described above, in which one or the other occurs depending on intensity. Rather, a single stress event, in a single individual, both aids and hinders learning…simultaneously!

That got your attention, didn’t it! Here is how it works. When we encounter a stressor, we first appraise it in the pre-frontal cortex, hippocampus, and amygdala, (in other words, predictive processing, baby![3], The Grand Unifying Theory of the Brain is back again!).

Then, the stress response is activated through the ANS, the autonomic nervous system (Koolhaas et al., 2011). The immediate response consists of adrenaline release, a pounding heart, and the fight-flight-freeze reaction; nothing we did not know already. But there is a lesser-known second response that is of interest to us. Cortisol, released through the hypothalamic pituitary adrenocortical axis (HPA) instantly increases plasticity and long-term potentiation in the brain areas related to the stressor, thereby allowing the individual to learn what stressed it. But it does more, in a way that Joëls et al. characterized as a “two-stage rocket” (2006, p. 156). As cortisol facilitates immediate learning related to the stressor, it also activates genetic change in neurons to suppress any other learning after the event, and to some degree, before. It is as if the brain makes sure that the thing that brought it harm is well internalized, with the related neural changes shielded from subsequent learning afterwards. In that way, our brains make sure those new stress-related memories become the most salient and don’t get mixed up with other things that happen. This super learning at the time of the stress event, and subsequent shielding, last for about an hour, until the neurons normalize.

[3] Many of the Think Tank editors and contributors see predictive processing as the primary function of the brain. See our Predictive Processing issue.

So, in that way, stress both facilitates and hinders learning at the same time, but keep in mind that what gets facilitated is related to the source of the stress. If you deride Ken for messing up past tense, he is more likely to learn that you are a threat, not that “ed” needs to be added to certain verbs. And his learning of other things will probably be derailed for the next hour.

The two-stage rocket effect of cortisol was an exciting thing to learn about. It gave me a clearer answer as to whether stress aids or hinders learning, and I have been thinking about it since. What does that mean for how I teach my classes? Can we use this stress-response system as a tool? Is it possible that we might misuse it? I have come up with a few ideas below to help us deal with classroom stress, but I would totally love it if you added more. In fact, I created a Facebook post where you can do just that. Drop by and leave us your two cents.

How stress affects our learners

In relation to teaching, consider:

that different people have different responses

We know we should be sensitive to diversity and handle some topics with care, such as sexuality, weight, ethnicity, money, parent’s jobs, or just parents as a plural, but there are other human shades we need to be sensitive to, such as introversion, neurodiversity (as in being dyslexic, for example), and whether a student has friends in the class. Some students feel a lot of anxiety working with partners they do not know. (See Heather McCulloch’s Embracing the Introverted Brain).

Presenting in class can be painful to some. Keep having students present, but be aware that poor performance might be caused by anxiety, not lack of preparation, and that lack of preparation might be caused by anxiety! It helps if you train your learners to be supportive listeners (and if you are one, too).

Use social contagion. Put learners who seem to enjoy class in the most visible places.

Find ways to hear from your learners, such as having them write a few sentences on end-of-class “communicards.”

Don’t assume that during pairwork, learners talking to each other in L1 is just bad behavior. As Harumi Kimura teaches us in Tapping into the Social Brain to Handle Class Incivility, it might just be a highly sensitive student helping another overcome anxiety.

As the William James quote at the top of this piece says, a big part of stress is how one interprets it, the stress mindset. If we view a stressor as enhancing, then it might be; if we view it as debilitating, it might be that instead. As Kelly told us, to some degree, seeing stress as helping or hurting is a choice, as with other mindsets. So, take the extra time to guide your students to positive interpretations.

Competitions and games can work in positive or negative ways for different learners. Be ready to help those having difficulties in ways that might reduce anxiety, like giving them some of the riddles or quiz questions—and even answers—in advance!

when we use it for behavior modification

Being criticized by a teacher can be highly stressful[4]. I realized about ten years ago that when I scold one student, I scold them all. And usually, when I praise one, I praise them all.

Hostility and fear have the same physical signs: crossed arms, frowning, distancing, unwillingness to engage. When a teacher reacts strongly to student behavior that looks like hostility or being uppity, when it is actually fear, it can cause unexpected harm.

The old chestnut that every student has to do the same thing and be treated the same way needs re-thinking.

that stress aids and hinders learning simultaneously

You might come down hard on a student for failure to perform in order to get her to work harder, but keep in mind that you have probably cut off her ability to learn anything (other than that you are scary and she is a failure) for at least an hour.

Asking students to perform again after failing a first attempt requires us to think about three things: 1) that the student needs some time for cortisol levels to drop before performing again; 2) that letting the learner decide to try again or not can turn distress into eustress; and 3) that asking one of her friends to help her “rehearse” the performance beforehand, somewhere in the back of the room, can work wonders.

This is pure speculation, but it is possible that a really active and exciting game in class might impact retention of what is taught after. Then again, maybe it is not pure speculation: I heard Paul Howard-Jones describe a study (sorry, no references) in which some students were asked to play an exciting videogame and others to watch TV before all of them did homework. Those that played the videogame (something more likely to cause cortisol release) showed lower retention of their homework. To me that study illustrated the shielding effect of cortisol.

[4] Just as I was writing this article, I was informed that my 12-year-old daughter’s social studies teacher told her that he was worried about whether she was getting it or not, since her test scores were mediocre. I also heard that after class, she broke into tears.


In short, “stress” is the problem child of animal sciences. The many definitions of stress in research and the general population are all over the place. In addition, stress can contradict itself, as it does with learning; or with rats: Rats experience cortisol release in social defeat and foot shock, but also in social victory and positive sexual behavior (Koohass, 2010, p. 1293). So, this bad boy is a good boy, too. But in its complexity lies opportunity. Learning about stress has changed a lot of my thinking about teaching, such as reconsidering the things I do to maintain control, and how I can add the edge that keeps learners engaged. Like other famous problem children—Mozart, Newton, and Jobs—who knows? This one might be bearing gifts as well.

Curtis Kelly (EdD.) is a professor at Kansai University, a founder of the JALT Mind, Brain, and Education SIG, and producer of the MindBrainEd Think Tanks. He has written over 30 books and given over 500 presentations. His life mission is “to relieve the suffering of the classroom.”

Leave a Reply

Your email address will not be published. Required fields are marked *