Stretch, Not Stress: Desirable Difficulties Explained

In classrooms where rigour is revered, the line between stretching students and stressing them is fine, sometimes razor-thin. How can we cultivate deep learning without tipping into anxiety, disengagement, or burnout? Enter desirable difficulties - a concept from cognitive science that offers a powerful lens for designing learning that is challenging but not crushing.

What Are Desirable Difficulties?

Coined by psychologists Robert and Elizabeth Bjork, desirable difficulties refer to learning tasks that feel effortful in the moment but ultimately strengthen memory and understanding over time. These are not arbitrary obstacles. They are intentional hurdles, like spacing, interleaving, retrieval practice, and variation, that slow learning down in the short term to make it stickier in the long term. The key word here is “desirable.” The difficulty must be within the learner’s zone of proximal development: hard enough to require thought, but not so hard that it becomes demoralising. It is, in essence, the sweet spot of cognitive tension.

Why Are They Important?

Modern education often mistakes fluency for mastery. When students can answer quickly, we assume they understand deeply. But fluency can be deceptive, sometimes it’s a sign of superficial familiarity rather than robust understanding. Desirable difficulties disrupt this illusion. They force students to wrestle with material, make mistakes, and revisit their thinking. This process not only strengthens retention but also builds metacognition, resilience, and independence. In the words of Robert Bjork, “Conditions that produce rapid learning often produce poor long-term retention and transfer.”

Examples in Practice

Here’s how desirable difficulties might look in the classroom:

• Retrieval Practice: Instead of rereading notes, students try to recall key ideas from memory. It feels harder but that struggle makes the learning last.

• Spacing: Revisiting content after a delay rather than cramming. It’s frustrating at first, but builds durable understanding.

• Interleaving: Mixing different types of problems or topics rather than practicing one skill repetitively. It’s confusing at first but trains flexible thinking.

• Varying Conditions: Studying in different contexts or using different examples strengthens the ability to transfer knowledge.

• Reduced Scaffolding: Gradually removing supports so students must engage more independently.

  
  

Stretch, Don’t Snap: Avoiding Overwhelm

While desirable difficulties are powerful, they must be introduced with care. When difficulty becomes undesirable, too opaque, unsupported, or emotionally taxing and it risks triggering stress responses that inhibit learning altogether.

Here are some principles to maintain the balance:

• Know your learners: What is desirable for one student may be overwhelming for another. This is especially important for neurodivergent learners or those with trauma histories.

• Build a safety net: Ensure challenge is scaffolded with emotional and academic support. A classroom high in psychological safety is more resilient to cognitive tension.

• Be transparent: Teach students why you're using these methods. When they understand that difficulty is part of the learning process, not a sign of failure, they become more willing to embrace it.

• Pair with coaching: Use coaching-style questioning to help students reflect on their strategies, not just their outcomes.

  
  

A Coaching Mindset

Desirable difficulties flourish in classrooms where struggle is normalised, feedback is formative, and identity is not tied to performance. Teachers in these environments act less like instructors and more like cognitive coaches, encouraging curiosity, modelling productive failure, and guiding students back into the learning zone when they wobble.

Challenge isn’t the enemy of wellbeing, unbuffered challenge is. When students are stretched with intention, supported through difficulty, and shown the rewards of effortful learning, they don’t just retain more. They believe more in their capacity to grow.