The goal of your instructional program is to free limited working memory from irrelevant mental effort.
Much depends on the degree to which the incoming material you already know. Or have other material to which you can make connections. Your existing knowledge — or schema to give it its psychological name — provides, in a manner of speaking, shelves upon which you can store the new information. Without such a network of shelves, you are left struggling to handle a surfeit of content with no where to put it. Its volume overwhelms you and you soon drop much of it to the floor.
So when you introduce new material to your class, ensure it is not completely new. Find out what the students already know and continually make connections. For this reason, metaphors and similes are powerful tools to achieve these necessary links.
Researchers have identified three types of overload in the classroom.
Intrinsic Load: This refers to the mental work involved in understanding the content of the lesson and achieving its goals.
Germain Load: Here, the overload includes information about the actual activities directed by the teacher. Don’t make instructions too complex!
Extraneous Load: Lastly, this entails mental work created that is irrelevant to the learning goal. This wastes limited valuable mental capacity.
When the learning goal requires a deep understanding, explanatory visuals that show relationships work best.
Stories are compelling. We use stories in the classroom to help us to make the material more interesting, relevant and exciting. But, it seems from what cognitive psychologists tell us, at the heavy cost of overloading our students’ working memories. Yes, motivating stories may indeed galvanise students and they embark on their learning full of glee but already half-full, cognitively speaking.
The same goes for background music. Yes, your students will tell you that they like it. And you may have fallen for the tale that it helps learning but — and it’s a big but — those party poopers, the cognitive psychologists, tell us time and again that the opposite is, in fact, the truth. Their clinical tests repeatedly show that extra incoming information overloads our cognitive system. Even if we like it.
Another cause of overload is something called split attention. That’s when you have to divide your time across two separate places to find the whole story. Such as when a graph in a book is explained on another page. Or when you have to look at two pages on a time-table to see your choice of trains. Mental energy is devoted to this non-productive effort when it could be better spent on the central task.
Use signals: Make your speech and writing concise. Ensure it is well chunked up — use plenty of paragraphs, emboldened topic sentences, arrows, pull-out quotes, boxes and bullet points.
Use visuals: At every opportunity, consider whether you could summarise the main points of the material in a graphic organiser. See over 36 graphic organiser HOW2s here. Ruth Clark is an expert on the impact of instructional techniques on cognitive overload. She has this to say on the matter, “When the learning goal requires a deep understanding, explanatory visuals that show relationships work best”.
Worked examples: Far more powerful than a list of success criteria — that threaten to overload your students with abstract concepts — worked examples demystify what success looks like. And how to achieve it. Talk through your reasoning as you go through the example, step-by-step. Then, perhaps, give them a list of success criteria afterwards, as the concrete example brings these often abstract checklists to life.
Use less: But perhaps the best advice is to be ruthless in cutting out an extraneous material. Not only will it not be needed, it will depress your students’ learning. Ouch!
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