Find Your Stretch Zone
Where the Comfort Zone Diagram Comes From, and How to Use It

You’ve probably seen the picture: a small circle labelled “comfort zone”, with bigger rings around it for fear, learning and growth. The message is simple. Step out, push through the scary part, and you come out bigger.

The picture has a longer history than it looks, and some parts of it hold up better than others. This page follows it back to an experiment with mice and looks at what the research supports. It ends with a simple way to size the next step for a skill of your own.

Where the zone diagrams come from

An experiment with mice

The story usually starts with Robert Yerkes and John Dodson. In 1908 they published a study of how fast mice learned a simple choice.

Each mouse had to choose between a white box and a black box. Going into the black box gave it an unpleasant electric shock. Forty mice took part.

The researchers changed two things: how strong the shock was, and how hard the two boxes were to tell apart.

• When the boxes were easy to tell apart, the mice learned faster as the shock got stronger, up to the strongest shock the researchers thought safe to use.
• When the boxes were hard to tell apart, both weak and strong shocks slowed learning. A shock nearer the weak end worked best.

The groups were small. In one set of experiments, only one pair of mice was trained at each shock strength. The authors also called one of their conclusions tentative, open to correction by later research.

Notice what the paper is about: shocks, mice and how fast they learned. The words arousal, anxiety and performance don’t appear in it.

How the experiment became a curve

The famous upside-down U came later. A 2007 review traces it to the 1950s, when Donald Hebb and others argued that performance rises with arousal and then falls. They did so, the review says, without citing Yerkes and Dodson.

According to the same review, Hebb’s single curve “incorrectly came to be known as the Yerkes-Dodson law”. From the 1960s on, the law shrank into one inverted-U curve in psychology textbooks.

A 1994 paper by Karl Halvor Teigen, a psychologist then at the University of Tromsø in Norway, traced the retelling. Later writers recast the law as the effect of motivation, arousal, anxiety or stress on learning and performance. Those changes, he wrote, “are often misattributed to Yerkes and Dodson themselves.”

Scholars still disagree about how much of the law survives.

• A 2007 review calls it “a well-cited, but misunderstood, century-old principle”. In its reading, the link between arousal and performance can be a straight line or a curve, depending on how hard the task is. It points to a 1957 study in which rats learned an easy task quickly under the highest level of stress, and a harder one best under a middle level.
• A 2015 paper on work stress examined the evidence for the law and found it wanting. It concludes that the law “has no basis in empirical fact”, and it looks at how the simple graph helped the idea spread.
• A 2024 lab study found the upside-down U in people’s moment-to-moment alertness, measured by pupil size. Performance peaked at middle levels in tasks where people spotted or told apart sights and sounds. Its authors note that, before this, the evidence for the curve in humans was “mixed at best”.

Our reading: the mouse study is real, but it says less than the curve suggests. Newer lab work supports the curve for alertness in simple tasks. Going from that to stress at work is still a long step, and scholars disagree on how much evidence fills the gap.

Vygotsky’s zone of proximal development

The idea of a zone just beyond what you can already do comes from somewhere else. The psychologist Lev Vygotsky (1896–1934) described a zone of proximal development.

An English edition of his writings, Mind in Society, was edited by Michael Cole and others and published in 1978. There, the zone is the distance between what a learner can solve alone and what they can solve “under adult guidance or in collaboration with more capable peers”. We read that definition as quoted in an introduction to his work, not in the book itself.

The definition says nothing about comfort or fear. Its key idea is help: what becomes possible when someone more capable works with you.

Senninger’s three zones

The three-zone picture comes from Tom Senninger, a German adventure educator. One account dates his learning zone model to 2000, the year his book on leading adventure-based learning came out.

Accounts of his model describe three zones.

• Comfort zone: what’s familiar, where you feel safe. One account calls it important too, as a place to return to, relax and recharge.
• Learning zone: just outside the familiar. Here you’re challenged, and you slowly expand your comfort zone by becoming more familiar with more things.
• Panic zone: beyond the learning zone. In this account, it is where learning is impossible, because fear blocks it.

One detail is easy to miss. The same account says “these three zones are different for different situations and different for each person”.

Where “comfort zone” came from

The phrase itself is older than any of these models. It was in print by 1923, in research on heating and ventilation. A paper that year for the American Society of Heating and Ventilating Engineers was titled “Determination of the comfort zone”.

Judith Bardwick’s 1991 management book Danger in the Comfort Zone uses it for behaviour at work, and is sometimes named as the phrase’s origin.

A definition you may have seen is Alasdair White’s, from a 2009 management paper. He calls the comfort zone “a behavioural state within which a person operates in an anxiety-neutral condition”. It is sometimes credited to Bardwick instead.

The four-zone diagram

The version with four rings, for comfort, fear, learning and growth, was online by April 2019: a writer reports seeing it then. That writer looked for its creator and found only people who had reposted it. We couldn’t find the original either.

Some accounts credit the four-zone version to Senninger’s 2000 model. Other accounts we read describe three zones, with panic, not growth, beyond learning. We couldn’t read his book to settle it.

The four-zone version has no panic zone, and it adds a fear zone before learning. In our reading, that changes the message: fear becomes a stage to push through, rather than a sign that a step may be too big.

Desirable difficulties

Learning research has its own version of stretch, but not too far: desirable difficulties. These are conditions that make learning feel harder but help it last.

In a 2011 chapter, Elizabeth and Robert Bjork give examples:

• varying the conditions of practice instead of keeping them the same;
• mixing topics instead of studying one at a time;
• spacing study sessions out instead of cramming;
• using tests instead of being shown the material again.

Robert Bjork coined the term in 1994. He and Elizabeth Bjork add a limit: a difficulty only helps if the learner has the background to respond to it successfully. Otherwise, it becomes an undesirable difficulty. Our Range summary covers this research in more depth.

Research on expert performance points the same way. Anders Ericsson and Robert Pool describe deliberate practice as “constantly pushing oneself beyond one’s comfort zone”, with activities designed by an expert and feedback to find and fix weaknesses. Our Outliers summary looks at how that idea became the “10,000-hour rule”.

What holds up and what doesn’t

Here are seven popular claims about comfort zones and the diagrams. Each verdict is about the claim as it’s usually stated.

“The phrase ‘comfort zone’ was coined in 1991”

Doesn't hold up The phrase is older: it was in print by 1923, in heating and ventilation research. Bardwick’s 1991 book uses it for behaviour at work, and her book has the phrase in its title, which may be why it gets the credit.

“Yerkes and Dodson showed that anxiety affects performance”

Doesn't hold up Their 1908 paper measured how fast mice learned under electric shocks of different strengths. Anxiety and performance were added by later writers, who often credited the change to Yerkes and Dodson. The later curve does carry their names, which makes the story easy to believe.

“A bit of stress improves performance”

Still argued Scholars disagree about how far the evidence goes. A 2007 review defends a version in which the most helpful level depends on how hard the task is. A 2015 paper finds no empirical basis for the law. A 2024 lab study found the curve for moment-to-moment alertness in simple tasks, which is not the same as stress. The mouse data did show a middle level working best on the hard task, which is part of why the idea feels solid.

“The learning zone model comes from Vygotsky”

Partly Senninger’s model is described as based on Vygotsky’s zone of proximal development, so the link is real. But Vygotsky’s zone is about what a learner can do with help from someone more capable. It says nothing about comfort, fear or panic.

“Growth only happens outside your comfort zone”

Partly Practice at the edge of your skill matters: deliberate practice points that way. Desirable difficulties add that some kinds of extra difficulty help learning last. But only goes further than the research we found. A difficulty helps when you can respond to it. Accounts of Senninger’s model do put growth in the learning zone, but they give the comfort zone a role too, as a place to recharge and reflect.

“Fear is a zone you must pass through”

Can't confirm We found no study that tests whether people must pass through a fear stage on the way to learning. In a 2022 study of 2,163 adults across five experiments, treating discomfort as a sign of growth made people engage more and feel they had made more progress. The authors write that growth “often requires experiencing discomfort”, and the effect appeared only where growth caused discomfort straight away. That is often, not always, and discomfort is not the same as fear.

“The zones are a ladder you climb once”

Doesn't hold up The three-zone model isn’t described that way. Accounts of Senninger’s model say the zones differ for each situation and each person, and that the comfort zone slowly expands as you learn. The four-zone version presents the zones as phases in order, which makes a one-way reading easy.

A redrawn diagram: the zones belong to the task

Here is our own version, in words. It isn’t a research finding. It’s a way to use the parts that hold up.

The zones belong to a task, not to you. You can be calm giving a toast to friends and frozen giving the same toast to a hall of strangers. So the useful question isn’t whether you are in your comfort zone. It’s where this next step sits.

For any one task, a step can sit in one of four places:

• Too easy: you can do it without much thought. Useful for keeping a skill, less so for building one.
• Stretch: you can do it with effort, some mistakes and perhaps some help. This is where Vygotsky’s help from someone more capable and Bjork’s desirable difficulties sit.
• Too big: you can’t yet respond to it, so most of your effort goes into coping. In Bjork’s terms, the difficulty has become undesirable.
• Panic: the step feels threatening, not just hard. The three-zone model keeps this zone; the four-zone diagram leaves it out.

Help moves the line. A step that is too big on your own can be a stretch with a teacher, a partner or a smaller version of the task.

Nerves aren’t the test. A stretch can feel uncomfortable, and an easy step can feel calm. The question is whether you can still respond to what the step asks of you.

The panic zone here is a word from teaching models, not a diagnosis. If fear or anxiety often gets in the way of everyday life, that is worth talking over with a doctor or a mental-health professional.

Worked examples

Here is how the zones might look for four common goals. They are examples of sizing a step, not recommendations.

Skill	Too easy	Stretch	Too big
Public speaking	Reading your notes aloud on your own	A two-minute talk to a few friends	A long speech to a full hall next week
The gym	A routine you can do half-asleep	One new exercise, learned slowly with good form	A weight far heavier than you have ever tried
A new language	Reviewing words you already know	A five-minute chat with a patient partner	A fast film with no subtitles
A career change	Reading about the new field	A short course, or a talk with someone who does the work	Quitting your job tomorrow with no plan

Notice that the stretch column often adds help or shrinks the step. The friends, the partner and the person who does the work all play the more capable helper in Vygotsky’s definition.

Try it: find your next stretch

You can do this on paper or in a notes app.

1. Name the skill you want to build.
2. Pick the next step and rate how hard it feels, from 1 (no effort at all) to 10 (overwhelming).
3. If it’s under about 4, make it harder. Add a little difficulty, an audience or a time limit, or use less help.
4. If it’s over about 7, make it smaller. Shorten it, slow it down, or bring in help.
5. Write down the step that feels like a 5 or 6.
6. Add one if-then plan: “If [time or situation], then I will [step].”

The 1 to 10 scale and the 4 and 7 cut-offs are our own rule of thumb, not research. We found no study that sets these numbers.

The if-then plan has more behind it. If-then plans help people follow through, though the effect is small once publication bias is allowed for. Our goal funnel guide covers them in more depth.

One stretch a week

A simple practice is to keep a one-line log. Once a week, write down:

• the skill;
• the step you tried;
• how hard it felt before you tried it, from 1 to 10;
• how hard it felt afterwards;
• the next step.

Over a few weeks, the log can show a step moving from stretch to easy, which is the comfort zone growing in the way the three-zone model describes.

Checking your progress has some research behind it. A 2016 meta-analysis of 138 studies found that monitoring progress helped people reach goals, more so when progress was recorded or shared. The weekly rhythm itself is a habit, not a finding.

How to use this

The parts that hold up suggest a few habits of mind.

1. Ask about the step, not about yourself. Whether a step is too easy, a stretch or too big is easier to answer than whether you are brave enough.
2. Resize the step, not the goal. A big goal can stay big while today’s step gets smaller or harder.
3. Count help as part of the stretch. A teacher, a partner or a simpler version can move a step into reach.
4. Treat discomfort as information, not a rule. It often comes with learning, but it doesn’t prove you’re learning. In the three-zone model, panic means the step is too big.
5. Read the old diagrams as sketches. The mouse study was about shocks, the stress curve came later, and the four-zone picture has no confirmed author.

For more on how beliefs about ability shape the way people meet a challenge, see our summary of Mindset and our look at popular mindsets. For deliberate practice and stretch goals, see our Grit summary. For learning many things at once, see what a Renaissance man is, and how to become one today.

Why it matters

“Get out of your comfort zone” is advice about a person. The research that holds up is about a task: a step that you can just about manage, often with help. Sizing that step, again and again, is what turns a diagram into progress.

Sources

The 1908 experiment and its retelling

• Robert M. Yerkes and John D. Dodson, “The relation of strength of stimulus to rapidity of habit-formation”, Journal of Comparative Neurology and Psychology 18 (1908), 459–482. Read in full at Classics in the History of Psychology (York University).
• Karl Halvor Teigen, “Yerkes-Dodson: A Law for all Seasons”, Theory & Psychology 4(4) (1994), 525–547, doi:10.1177/0959354394044004. We read the abstract.
• David M. Diamond, Adam M. Campbell, Collin R. Park, Joshua Halonen and Phillip R. Zoladz, “The temporal dynamics model of emotional memory processing: a synthesis on the neurobiological basis of stress-induced amnesia, flashbulb and traumatic memories, and the Yerkes-Dodson law”, Neural Plasticity (2007).
• Martin Corbett, “From law to folklore: work stress and the Yerkes-Dodson Law”, Journal of Managerial Psychology 30(6) (2015), 741–752, doi:10.1108/JMP-03-2013-0085. We read the abstract.
• L. Beerendonk, J. F. Mejías, S. A. Nuiten, J. W. de Gee, J. J. Fahrenfort and S. van Gaal, “A disinhibitory circuit mechanism explains a general principle of peak performance during mid-level arousal”, PNAS 121(5) (2024), e2312898121.

Vygotsky and Senninger

• L. S. Vygotsky, Mind in Society: The Development of Higher Psychological Processes, edited by Michael Cole and others (Harvard University Press, 1978), p. 86, as quoted in Harry Daniels (ed.), An Introduction to Vygotsky (Routledge, 2005), read as short searchable passages through Open Library.
• Library of Congress name authority, “Vygotskiĭ, L. S. (Lev Semenovich), 1896-1934”.
• Tom Senninger, Abenteuer leiten – in Abenteuern lernen (Ökotopia, 2000), catalogue record in the German National Library. We did not read the book.
• ThemPra Social Pedagogy, “The Learning Zone Model”.
• “Enhancing Medical Education: A Pathway to Nurturing Future Healthcare Professionals”, Cureus (2024), on the three zones.
• “Tourists’ apprehension toward choosing the next destination: A study based on the learning zone model”, Frontiers in Psychology (2022), for the date of Senninger’s model.

The phrase “comfort zone”

• F. C. Houghten and C. P. Yaglou (Yagloglou), “Determination of the comfort zone”, ASHVE Transactions 29 (1923), 361, as cited in P. O. Fanger, Thermal Comfort and other books, read as short searchable passages through Open Library.
• Judith M. Bardwick, Danger in the Comfort Zone (AMACOM, 1991), catalogue record on Open Library.
• Alasdair White, From Comfort Zone to Performance Management (White & MacLean Publishing, 2009), definition as quoted on the author’s own publications page.

Difficulty, practice and discomfort

• Elizabeth L. Bjork and Robert A. Bjork, “Making things hard on yourself, but in a good way: Creating desirable difficulties to enhance learning”, in Psychology and the Real World (2011), pp. 56–64.
• Anders Ericsson and Robert Pool, “Malcolm Gladwell got us wrong”, excerpt from Peak, Salon, 10 April 2016.
• Kaitlin Woolley and Ayelet Fishbach, “Motivating Personal Growth by Seeking Discomfort”, Psychological Science 33(4) (2022), 510–523.

Plans and progress

• Paschal Sheeran, Olivia Listrom and Peter M. Gollwitzer, “The when and how of planning: Meta-analysis of the scope and components of implementation intentions in 642 tests”, European Review of Social Psychology 36(1) (2025; online 2024), doi:10.1080/10463283.2024.2334563.
• Benjamin Harkin et al., “Does monitoring goal progress promote goal attainment? A meta-analysis of the experimental evidence”, Psychological Bulletin 142(2) (2016), 198–229.

Checked October 2026.

Related: From big goal to today · Mindsets checked · Range summary