The first TeachingSupport workshop, which focused on minimizing cognitive load to maximize learning, used the following analogy:
Think of working memory as an empty glass. Once you fill it with water, adding more water will result in it spilling out. When you provide your students with too much information, some of it won’t be taken in and it’s as if you never taught it.
Consider what would happen if you attempted to add water to a glass already filled with something. Well, you would be able to add as much water to the glass ,and your final result would be something different from what you started with.
Our students’ minds are not empty glasses; rather, our students come into our classrooms with minds already filled with hopes, dreams, fears, and knowledge about the world and how it works. What this means is that all of our students will have had some exposure to our particular disciplines, either through their K-12 schooling, popular culture, family and friends or through their own everyday experience. Not surprisingly, their knowledge will have varying degrees of accuracy.
Before they take a college history course, students may think that the most important skill that historians need is a good memory because historians need to remember a lot of names, dates and facts. Yet as the Decoding the Disciplines model suggests, historians consider history to be primarily about “interpreting sources to explain and seek answers to the past,” as Joan Middendorf, et al, note in “Making Thinking Explicit: Decoding History Teaching.”
Or, students enrolled in a science course, in this example, may begin a course with ideas reinforced by their everyday experiences and intuition. As the Private Universe project shows, many individuals believe that the cause of the seasons is due to the earth’s orbit around the sun. Find out if this belief is correct by taking the following survey and comparing yourself to elementary, secondary, high school and even college students and their teachers.
And, as a particularly timely note, if you think only famous basketball players have misconceptions about science, You Won’t Believe This One Insanely Weird Trick that we did in our workshop, which you can experience via video. It. Will. Blow. Your. Mind. Seriously.
While prior knowledge can hinder learning, it can also help, as another example from our workshop showed: Go ahead, try it out. The examples and analogies we draw on do matter. Indeed, teachers in STEM fields often use analogies to draw on students’ prior knowledge and help them comprehend a topic. However, teaching with analogies has limitations: After all, telling someone the earth is round can be understood to mean that the earth is round and flat, like a pancake.
Simply supplying individuals with accurate information doesn’t work on its own, and there are many reasons for this – which I’ll explore in next blog post incorporating teaching strategies for addressing prior knowledge. For now, I’ll note one research study that makes it clear that students’ prior knowledge simply cannot be ignored or dispelled by providing accurate information: As Brendan Nyhan and Jason Reifler observe in their article, the “backfire effect” helps us understand why conservatives who believed that Iraq had weapons of mass destruction (WMD) were even more likely to believe that after they were corrected. In other words, correct and accurate information actually strengthened and increased their misperceptions.
For more on these closing points, and a set of new insights, watch for next Monday’s posting of Prior Knowledge:Impacts on Student Learning, Part 2.