Building Knowledge, Building Readers: Why Background Knowledge Is Crucial for Reading Comprehension

If you’re a reading teacher, you’ve probably heard about the need to teach phonics systematically. That kind of instruction is crucial—but it’s not enough to ensure your students will understand the increasingly complex text they’ll encounter as they advance through school and through life. The typical approach to teaching reading comprehension, with a primary focus on skills and strategies, also won’t ensure their academic success.

Scientists have found that reading comprehension depends heavily on knowledge. If a reader is lacking a minimum threshold of background knowledge related to the text, no comprehension skill or strategy will help.

Readers with knowledge of the specific topic they’re reading about—for example, baseball—have a big advantage. And people who have a lot of general academic knowledge and vocabulary have better general reading comprehension. So if we want to improve students’ reading comprehension, we need to focus on building their academic knowledge and vocabulary rather than on supposedly abstract reading comprehension skills.

It’s also important to familiarize students with the sentence structure of written language, which is more complex than the sentence structure we use in conversation. They need to be able to understand constructions like subordinating conjunctions, such as although, and appositives, which are phrases describing a noun. Teaching students to use that kind of sentence structure in their own writing can equip them to understand it when they encounter it in text.

Why is prior relevant knowledge so important to reading comprehension—and to learning in general? It has to do with “working memory,” the aspect of our consciousness that tries to understand new information. Working memory is very limited. On average it can hold only four or five items of new information for about 20 seconds before it becomes overwhelmed.

If, however, we have relevant information stored in long-term memory, and if we can retrieve that information when we need it, we don’t have to juggle it in working memory as a new item. That expands the capacity of working memory to process new information.

But first, we need to be able to transfer new information to  long-term memory—and to retrieve it from long-term memory when we need it. To accomplish both of those things, one helpful technique is to explain the information in our own words.

That, of course, is what we do when we write. So having students write about what they’re learning, in a manageable way, makes the information stickier and easier to retrieve.

Do we really need to start building academic knowledge in the early grades? Absolutely. The longer we wait, the harder it is to narrow gaps between good and poor readers.

That’s because prior relevant knowledge doesn’t just help you understand what you’re reading; it also helps you retain new information. As reading expert Marilyn Jager Adams has said, knowledge is like mental Velcro^®: it sticks best to other related knowledge.

Children who come to school with more academic knowledge, or one half of the “Velcro,” can understand more complex text and retain new vocabulary from that text, which then enables them to read yet more complex text. The other students fall farther and farther behind as the years go by, especially if they’re limited to reading simple text at their “level.” By the time students get to middle or high school, the gap between these two groups of students can be huge and quite difficult to narrow.

Here are five key things that teachers can do to improve literacy instruction and equip their students for academic success in years to come:

1. Organize read-alouds by topic rather than skill-of-the-week. Read-alouds should be primarily whole texts, not excerpts. They should also be more complex than texts students can read independently, so that children become familiar with the concepts, vocabulary, and syntax that will eventually enable them to read complex text on their own. It’s best to spend at least two or three weeks on a topic, so that students get repeated exposure to the same key concepts and vocabulary.

2. Ask questions that put content in the foreground. This is where you can bring in comprehension skills and strategies—as long as they’re appropriate to the particular text and grounded in its content. Having students talk about the content of a text will help them transfer new information and vocabulary to long-term memory.

3. Organize classroom libraries by topic, not just reading level. If you’ve been reading about and discussing a particular topic, have a basket of books available on that topic, at varying levels of difficulty. Once students have acquired some knowledge of the topic, you might be surprised at the level they can read at.

4. Spend lots of time on social studies and science topics. Of course fiction and poetry have their place, but content-area topics seem to have the most potential to build the kind of knowledge that fuels reading comprehension.

5. Have students write about what they’re learning, in any subject. Not only can that boost their retention and understanding of the content, it can also develop analytical thinking abilities. But it’s also important to explicitly teach students how to write, beginning at the sentence level. Otherwise, they may be so overwhelmed by the cognitive demands of writing itself that they won’t get its potential knowledge-building benefits.

Adopting these five practices can help set your students on the path to success in school and in life. For more information on them, click here to watch a webinar on the topic.