Students’ prior knowledge can help or hinder learning
By Michele DiPietro
If we are not intentional about students’ prior knowledge, we might default to a way of teaching that treats students as blank slates that we aim to fill with knowledge. This is as ineffective as it is untrue.
The first principle of learning concerns students’ prior knowledge. It comes first because their prior knowledge is set before they even enroll into our course, and it determines, for better or for worse, future learning and performance (Ambrose et al. 2010). This might sound like a truism, but it is important to be intentional about students’ prior knowledge. If we are not intentional about students’ prior knowledge, we might default to a way of teaching that treats students as blank slates that we aim to fill with knowledge. This is as ineffective as it is untrue, but understanding the research on prior knowledge will help us better direct our efforts.
Ideally, all prior knowledge will be in service of new learning. Students will use what they know as the foundation, the building blocks for new knowledge. This is certainly true in a lot of cases, but the opposite can happen as well. What students know sometimes acts as an impediment, a stumbling block, and it can limit learning as well as performance. Research identifies four such situations: prior knowledge can be Inappropriate, Inactive, Insufficient, and Inaccurate.
- Inappropriate Prior Knowledge. Sometimes, our prior knowledge tricks us into a false sense of security. We are confident about our knowledge and abilities in a specific context and we make unwarranted generalizations. When we are learning a second language, we often embarrass ourselves because we project vocabulary or sentence constructions that are perfectly fine in our native language onto the target language, with awkward results. Other times, we are tricked by the everyday meaning of technical words. For instance, many students struggle with the concepts of “range” and “spread” as they relate to statistical variability because they are confused by the common usage of the words (Kaplan et al. 2009). Or even, we might have learned things in one disciplinary context and have trouble adapting them to another. As an example, students might learn how to take notes in a first-year seminar, with the underlying context being that of listening to a math lecture. When they try to apply the same note taking strategies to a discussion where multiple people are talking and disagreeing with each other, they might become frustrated. Strategies to deal with Inappropriate uses of prior knowledge. The research documenting these situations points to the fact that it is not enough just go over facts and concepts. We must also point out discrepancies between technical usage and everyday usage. It is also very helpful to highlight the conditions and the limits of applicability, or, even better, to prompt students to think about where those concepts would easily extend to and where they would fail. Prompting students to think about why those concepts would transfer or generalize, and why they wouldn’t, helps students solidify their understanding.
- Inactive Prior Knowledge. It is astounding how much information an adult brain encodes. Equally astounding is the fact that most if the knowledge in the brain lies there inert. The brain simply does not have the capacity to activate all the knowledge it possesses. We commonly describe this phenomenon as compartmentalizing knowledge. The implication of the finding is that even if students have learned relevant information, there is no guarantee they will use it, because they fail to recognize it is relevant (Gick and Holyoak 1980). For instance, they might not apply certain calculus concepts to physics, or to engineering. For knowledge to be useful, and to be used, it must first be activated. Strategies to help students activate their prior knowledge. If students have indeed learned the concepts we want them to use, helping them activate it is actually easy. Even simple prompts suffice, such as “Remember last week when we talked about the separation of powers?” or “Go back to the chain rule from Calculus I.” Of course, we don’t want our students to be eternally dependent on our prompts to activate their prior knowledge. A better long-term approach might to encourage them, every time they are stuck, to ask themselves what they already know that might help them (Peek et al. 1982).
- Insufficient prior knowledge. The strategies in the previous section are predicated on students actually possessing the relevant knowledge. Unfortunately, that is often not the case and students may possess gaps in their knowledge. In particular, they might know the definition of a concept (declarative knowledge) but not be able to apply the concept in practice. Or, they might be able to execute a technique by rote (procedural knowledge) but not understand the conceptual underpinnings that make it work. We tend to assume declarative knowledge as a proxy for procedural, and vice versa, but they don’t always go hand in hand (Anderson & Krathwohl 2001). Furthermore, students are not always good at diagnosing the gaps in their knowledge and might be surprised midcourse when they are struggling (Dunning 2007). Strategies to help students activate their prior knowledge. The first step is to identify the prerequisite knowledge necessary to succeed in the course—not just concepts, but what we expect student to be able to do with the prerequisite knowledge. Prior knowledge assessments in the first week of the course are very helpful, such as quizzes and problem sets on the prerequisite knowledge. As mentioned, students are not good with self-diagnostics, but they improve drastically once we ask them to rate their abilities (e.g., I’ve never heard of this concept; I know we covered it in a previous course but I don’t really remember it; I can apply it to solve problems but I get stuck sometimes; I can use it to solve problems all the way through; I am so confident in my knowledge I could teach it to my fellow students). Still, they might be very accurate in placing themselves on this continuum but not be where they are supposed to be. At this point we need to decide on option for catching students up. Depending on how many students exhibit gaps, and on how crucial filling these gaps is, we might decide to dedicate some review session during class time to go over the course materials. We might create handouts or videos and offer links to existing web resources such as the Khan Academy. We might offer to go over some of the material during office hours. If we have a GTA, we could offset some of the reviewing to them. Or we might direct students to existing campus support, such as supplemental instruction, tutoring, writing support, or other activities. If students don’t understand how the prerequisite knowledge connects to the new material and how crucial the remediation is, they won’t invest as much effort in it, so we need to articulate clearly its importance.
- Inaccurate prior knowledge. The most troublesome situation happens when we think we know something but we are wrong. Our brain tricks us into a false sense of security with knowledge that feels true but is verifiably false. The phenomenon of misconceptions—theories and models deeply embedded in people’s thinking but empirically inaccurate—has been documented in several fields, starting with physics and sciences (misconceptions about the shape of the earth, velocity, electricity, pressure, and so on), psychology (e.g., hypnosis, left/right brain), and sociology (stereotypes about certain groups of people). Mazur (1996) documents how some students can be as confident as they are wrong about their misconceptions. When students harbor misconceptions, they need to unlearn them before they can learn new, accurate knowledge, but this process can be challenging, depending on how entrenched misconceptions are. If letting go of one misconception implies letting go of a second one connected to it, and then a third one, and so on, the brain can develop mechanisms to protect itself from this snowball effect. Some students might discount information that disproves what they know while giving extra weight to notions that reinforce what they already believe in, a process called confirmation bias (Wason 1960). They might develop a practiced skepticism toward science, claiming that one can always find a study that contradicts other studies, so no science is worth paying attention to, or what some term the Scientific Impotence Excuse (Munro 2010). Some researchers have even documented a kind of “backfire effect” where the more data, evidence, facts, figures, are provided in support of a position, the more entrenched some students become in the opposite, unsubstantiated one (Nyhan and Reifler 2010). Strategies to dispel inaccurate prior knowledge. Given these findings, it is no surprise that dispelling misconceptions can be quite challenging. Research has not identified a silver bullet, but we do have some guiding principles. If the problem is the skeptic attitude toward science, we need to give students tools to help them distinguish science from pseudoscience. Lilienfeld (2011) has compiled a list of “ten commandments” in this respect, available here. If the issue is that of unexamined beliefs, the key is to get students to examine them (Minstrell 1989). If we can get students to reason on the basis of their inaccurate prior knowledge, use it to make predictions, eventually they will arrive at demonstrably false assertions. If they already possess prior knowledge in a different context that contradicts their misconceptions, we can activate that prior knowledge in the hope of generating cognitive dissonance.
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