Central to cognitive load theory is a basic understanding of schema theory. Briefly, our long-term memory does not store information in the same way as a library or a computer, it stores it as interrelated webs of ideas. Above is a diagram I created to help explain the idea to colleagues.
The schema in the diagram is for marsupials and knowledge of a new marsupial is in the process of being added. In this case, the new knowledge is being ‘assimilated’. In other words, it is simply being bolted on to the existing schema. The connection with other components of the schema are growing over time – retrieval practice may be one way of strengthening these connections. Schemas are also not isolated units. The components that are shaded with two colours are intended to represent the fact that these element are also part of other schemas. The individual who possesses this particular schema appears to be uncertain of whether the platypus should be in there.
In some cases, new knowledge cannot be added to a schema without deforming it in some way. This may be, perhaps, because it adds a deeper insight or makes a connection that was not previously present. This process is known as ‘accommodation’ rather than assimilation.
One way of thinking about the role of long-term memory in solving problems or dealing with new information is that entire schema can be brought readily into working memory and manipulated as a single element alongside any new elements that we need to process. The normal limits imposed on working memory fall away almost entirely when dealing with schemas retrieved from long-term memory – a key idea of cognitive load theory. This illustrates both the power of having robust schemas in long-term memory and the effortlessness of deploying them; an effortlessness that fools so many of us into neglecting the critical role long-term memory plays in learning.
Some constructivists conclude that, because schemas involve relating new concepts to similar concepts already in long-term memory, we have to ground learning in everyday life or supposedly relevant examples. I don’t think this is implied at all. Instead, we need to build schemas carefully and systematically so that students can learn important ideas regardless of their everyday experience.