Filling a Balloon with Water

A leaking water-filled balloon.
A leaky bag filled with water serves as an analogy for the pressure on the working memory. Image: 77 Fotos

The challenge of working memory. Imagine filling a balloon with water. Keeping the balloon open whilst pouring in the water is challenging. As capacity is reached, excess water spills over, even going in many directions. If the balloon is degraded by sunlight or has sustained a small hole, the water seeps out. This is like our working memory. Too much input, competing sources of information and limited capacity affect its ability to manage and manipulate complex information.

Working memory is a key element of executive function. It is crucial to learning, reasoning and making sense of the world. CAST explains that working memory is limited for every learner, but can be further limited in learning difficulties. So, what can we do to support learners?

Key Strategies to Support Memory

All of the following strategies are taken from Pooja K. Agarwal, PhD and Patrice M. Bain, EdS from Powerful Teaching.

Retrieval practice

“Retrieval practice” is a learning strategy where we focus on getting information out of our brains. Through the act of retrieval, or calling information to mind, our memory for that information is strengthened and forgetting is less likely to occur. Retrieval practice is a powerful strategy for improving academic performance. It requires no special technology, no cost and no significant additional class time.

Spaced Practice

Spaced practice involves taking a given amount of time devoted to learning and arranging that time into multiple sessions that are spread over time. In this way, the learning sessions are said to be “spaced” apart in time. Contrast this with cramming, where learning is conducted in a short, massed manner.


Interleaving supports learning by mixing related concepts, encouraging students to discriminate between approaches or similarities or differences. Often used in maths, practice problems are interleaved if the maths problems are arranged so that the same strategy cannot solve consecutive problems.


Feedback-driven metacognition develops students’ cognition of what they know, and what they don’t. It can be valuable in guiding students’ decision-making when learning, applying and transferring skills or strategies.

Future posts will explore practical strategies related to each of these concepts. They will be linked to this post once released.

Many more practical, easy-to-implement strategies for supporting executive function and accessing the curriculum are suggested in previous UDL File posts. Or check out the CAST UDL framework.

There is more about Universal Design for Learning on this website.