Our active working memory is amazing. It’s where thinking takes place. New information gets mixed in with things already stored in your long-term memory and is processed. Some of what you process gets written back into your long-term memory—this is learning.
Yet, our active working memory also presents a huge bottleneck to learning. Research suggests it only holds three to five items for 10 to 20 seconds. Yikes. The demands we place on our very limited active working memory are known as cognitive load.
If the total cognitive load on students is too high, learning is hard or impossible. One scenario is that their working memory just can’t hold all the new stuff at once (we’ve all felt like this at times). Or, they might have enough capacity to hold and process everything but no “extra” space to write schema in their long-term memory. This presents itself as students being able to do a task in class but not being able to do it later. If it hasn’t been stored in long-term memory, it hasn’t been learned.