I am about a third of the way through John Hattie and Gregory Yates' book Visible Learning and the Science of How We Learn. Two main principles have stuck out as important: cognitive load and prior knowledge. They are interesting, in part, because in today's schools we seem to be minimizing their impact on student achievement.
"A major determinant of knowledge acquisition will be what the mind already knows" (p. 114). When the CCSS emerged, the reading people suggested that teachers should not work at actively activating prior knowledge and that through close reading all would be revealed. You might be able to learn it through close reading of a passage that you know little about, but we do not have to make ourselves work that hard. Teach strategies to help students approach a text by pulling what they know from their background. If they know nothing, the passage will be meaningless. (I keep thinking about a book my son brought home in kindergarten to read. It was about a bunny doing lots of different dances- fox trot, waltz, rumba, etc. Oddly, my son who had little knowledge about dancing, did not really get the book, even though he could read it. His vocabulary was not up to the task of comprehension.) Hattie points out that "prior knowledge effects readily outweigh the effects due to IQ or … 'learning styles'"(p. 114). We need to develop a foundation on which to build information. If you do not have a tree, it is hard to hang ornaments. Sometimes this means we need to watch a video clip, hear a story, go on a field trip, work with realia, read an easier passage first or preview vocabulary to help understand what we are going to try to learn. Using these strategies helps us to get the information into our heads in a meaningful way. We get things into long term memory by linking to things that are similar and retrieve them based on how they are different. Without a system to encode, we will struggle to meaningfully interact with the material.
My least favorite part of teaching is unteaching- taking some misconception that a student has and replacing that knowledge with the truth. It takes twice as long to actively unlearn as to learn. This is prior knowledge showcasing its power. I would way rather build the foundation than have to tear down someone else's work. We need to be very careful with what we teach. You can actually subtract a bigger number from a smaller number, in spite of what our first grade teachers tell us. You just get a negative number. Contrary to what the movie Ice Age portrays, glacial movement is really slow and the density of animals on glaciers is really low. Veins are not blue, nor is deoxygenated blood. The Sun is not closer to the Earth during summer than winter. Columbus landed in the Caribbean and never knew he had not landed in the East Indies. Need I go on?
Cognitive load is the level of effort the brain is asked to engage in. The brain can only do so much. This is why prior knowledge is so important. When you have something learned to an automatic level, it loads the brain in a limited manner. When you are working with new things, problem solving, or doing higher level thinking, your cognitive load is high. So we need to be careful not to overload students' cognitive capacity at any one time or they will be unable to function with any level of efficiency. When it comes to inquiry learning the "additional load imposed by the need to explore and find thigs out can detract from our capacity to assimilate the information" (p. 78). That is why inquiry approaches require so much time and scaffolding- "the effort involved [in problem solving] detract from the overall knowledge building process and can make further less likely" (p. 152). Lecture can be powerful because, done right, it presents small chunks of information in a meaningful framework so that students can learn it. The more a student knows, the more they can "discover" on their own. While short term memory can hold 7 pieces of information, working memory can only operate or use 2-4 pieces of new information, it can use more items if they are from long term memory (p. 146).
We know that students with ASD struggle with generalization. Perhaps cognitive load explains a great deal of this. They are less adept at processing sensory information so their working memory is overloaded. Consequently they cannot generalize from the problem solving involved in socialization. This leads one to conclude that explicit learning needs to be used to take a skill to the automatic level before it is combined with other skills.
When we teach, we need to aware of these two concepts because they determine what a student will get out of instruction. They require careful and thoughtful building from the student's individual place, not the curriculum's place.
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