By Marilyn Jager Adams

Marilyn Jager Adams, a visiting scholar in the Cognitive, Linguistic and Psychological Sciences Department of Brown University, is internationally regarded for her research and applied work in cognition and education, including the seminal text Beginning to Read: Thinking and Learning About Print. This post, which originally appeared on the Shanker Blogis adapted from Literacy Ladders, an anthology of articles on early childhood literacy learning.

Literacy Ladders Cover


The very purpose and promise of schooling is to prepare students for responsible adult lives—to be civically minded and informed, to pursue higher education, and to find gainful work that allows them to grow and contribute to society. To accomplish this, students must be given ample support and practice in reading, interpreting, and writing about texts as complex as those that characterize life beyond high school. But here lies our great dilemma. Increasing the sophistication of assigned texts, all by itself, is unlikely to do much good. After all, we know that many students are unable to understand such rigorous texts, and nobody learns from texts that they cannot understand.

What this means is that we, as educators, need figure out how to help raise our students’ language and literacy skills to levels that enable them to understand and gain from complex texts. Working with the Albert Shanker Institute, the American Federation of Teachers, and Core Knowledge Foundation, I recently helped produce an anthology of research essays — Literacy Ladders — that addresses this challenge. Below are a couple of the key takeaways.

Comprehension Depends on Knowledge

The overarching theme of these essays is that if we wish to advance our students’ literacy, we must devote ourselves to increasing the breadth and depth of their domain knowledge.

Through language, novel concepts are communicated in the form of novel combinations of familiar concepts. That is, new concepts and the meanings of new words can be verbally explained only in terms of known words. Sometimes a new word can be adequately explained by comparing and contrasting it with familiar concepts (e.g., a mayfly looks like a giant mosquito but it is harmless). Otherwise, we must define the word by decomposing it into familiar concepts and then piecing together the whole. Either way, the usefulness of the effort depends on the familiarity of the supporting concepts we offer.

Yet the role of prior knowledge runs far deeper. The core definition of a word is only a tiny fragment of the meaning that makes it useful in understanding language. Neuroimaging confirms that the full meaning of a familiar word extends broadly through the mind, including associations to every trace that your experience with that word or its concept has left in your memory. For instance, your full knowledge of the word “apple” extends to the traces in your memory of the many apples in your life and how they have looked, felt, tasted, smelled, or sounded (e.g., when you bit into, dropped, or sliced them); of where you were and what else and who else was there with each apple; of picking apples, peeling apples, and bobbing for apples; of cider, apple pie, caramel apples, and Waldorf salads; of apple trees, teachers’ apples, and poison apples; of “rotten apples,” “apple-cheeked,” “apple a day,” and the “Big Apple;” of Adam and Eve, William Tell, George Washington, Steve Jobs, the Beatles, and so on. The more strongly or frequently any such association has been tied to the apples in your life, the more strongly it dominates your overall concept of an apple. But all of your experiences, be they direct or linguistic, are there — waiting to be activated and used in making sense of “apple” the next time you see or hear the word.

When you encounter “apple” in conversation or text, it will automatically activate its entire, extended complex of associations in your mind, and the same thing happens when you encounter each successive word in the sentence. As the associations tied to each ensuing word in the sentence become activated, subsets of knowledge from different words that overlap effectively become “superactivated.”*

Alternatively, consider what happens if — whether due to vocabulary or reading difficulties — you cannot recognize a word at all. What you lose is not just the meaning of that particular word, but also the work it was supposed to do in providing context and precise meanings for the other words around it. In between — to the extent that you recognize the word but have scant knowledge of its meaning and usage — your understanding is commensurately impoverished.

In other words, knowledge is the medium of understanding and therefore of reading with understanding.

Topical Units Can Help

Research demonstrates that, for comprehension, relevant knowledge is even more important than general reading ability. When high- and low-knowledge groups are divided into good and poor readers, those with little knowledge relevant to the text at hand perform relatively poorly, regardless of how well they read in general. In contrast — and this is important — the performance of the poor readers with higher background knowledge is generally better than that of the good readers with less background knowledge, and nearly as good as the good readers with lots of background knowledge.

Prior knowledge about a topic is like mental velcro. The relevant knowledge gives the words of the text places to stick and make sense, thereby supporting comprehension and propelling the reading process forward. In one study, scientists monitored readers’ eye movements while reading about topics that were more versus less familiar to them. Given texts about less familiar topics, people’s reading slowed down and the progress of their eye movements was marked with more pausing and rereading. In other words, not only do readers with less topic-relevant background knowledge gain less from reading about that topic, less-knowledgeable readers must also expend more time and effort to arrive at what limited understanding they do gain.**

What does information have to do with text complexity? They are closely related in two important ways. On one hand, texts that are more complex in vocabulary and syntax also tend to be more presumptuous of readers’ background knowledge. On the other, texts that strive to present more precise argument or more specific information on a topic are unavoidably more complex in vocabulary and syntax. In order for students to become comfortable and competent with these sorts of texts, they must first develop a supportive understanding of the broader topic under discussion. And that’s where topical units come in.

In a topical reading unit, all texts are about some aspect of a single main concept. Topical readings provide a natural and highly productive way of revisiting and extending learning. Across readings, as the books build interlaced networks of knowledge, the similarities, contrasts, and usages of the words gain clarity. In tandem, the stories gain plot and excitement, and the informational texts gain structure and provoke wonder. Further, as the knowledge network is enriched, the mind is ever better prepared to understand the language of each new sentence.***

The deeper domain knowledge that topical units help students acquire is of inestimable importance in itself, but topical units also bring a number of other benefits. Direct benefits include increases in reading fluency, accelerated vocabulary growth, and improvements in the spelling, style, organization, and ideas in students’ writing. Because topical units offer a means of scaffolding texts, they allow students to rapidly work their way up to engage productively with texts that would otherwise be beyond their reach. In turn, experience in understanding more sophisticated texts brings additional benefits. For example, an expert oceanographer can be expected to penetrate an advanced text in oceanography with ease. However, people who have engaged deeply with complex information in any scientific field —  experts in biogenetics, mineralogy, physics, or marine biology, for example — could be expected to be able to understand the same text far better than a person without any specialized knowledge (even if with significantly more effort than the oceanographer). The advantage of the oceanographer is due to the fact that knowledge is domain specific.****

The advantage of the other well-read scientists is due to the fact that the modes of thought and analysis that deep knowledge affords are part of the literate mind and can be applied across known andunknown domains.

Can advanced texts really be made accessible to less proficient readers in this way? Yes. As a concrete example, no text on dinosaurs would get through a readability formula for second-graders. However, having built up their vocabulary and domain knowledge in an area of interest, many second-graders are able to read and understand remarkably sophisticated texts about dinosaurs with great satisfaction. Gradually and seamlessly, students build the knowledge networks that prepare them to tackle texts of increasingly greater depth and complexity.


* For an educator-friendly review of the neural connections from letters to meaning, see: M. J. Adams, “The Relation between Alphabetic Basics, Word Recognition and Reading,” in What Research Has to Say about Reading Instruction, 4th edition, eds. S. J. Samuels and A. E. Farstrup (Newark, DE: International Reading Association, 2011), 4–24.

** For a summary of the studies in the preceding two paragraphs, see Willingham’s “How Knowledge Helps: It Speeds and Strengthens Reading Comprehension, Learning—and Thinking.” p. 42 in Literacy Ladders.

*** Be warned: Some reading programs mistake what might better be called “thematic units” for topical units. As a quick rule of thumb, if it is a topical unit, then the word or words naming the same core concept should appear frequently in every text. Note: Superficial treatments and texts about different concepts labeled with the same word don’t count.

**** E. D. Hirsch, “Beyond Comprehension: We Have yet to Adopt a Common Core Curriculum that Builds Knowledge Grade by Grade–But We Need To,” p. 54 in the Literacy Ladders.

5 comments on “Knowledge For Literacy”

  1. 1
    Merriol Almond on May 19, 2015

    I would also emphasize importance of a basic knowledge of biology, chemistry and especially physics. We insisted our four children have a year of each in high school. It’s striking what you can understand with a good grasp of basic knowledge in these three fundamental fields, whether farming, aviation, climate change, etc and you are essentially living in the Middle Ages without this essential substratum for understanding the world around us. Add a basic grasp of probability and statistics and potential sources of bias. You need these virtually everyday to understand what you read and what you experience.

  2. 2
    Amanda on May 19, 2015

    Prior knowledge is so important as a building block for reading comprehension. As a teacher when I have students in my class who struggle with English because it is a second language to them and understanding is limited, it takes much more involvement with them to establish some sort of basis in which to build upon. This is not a bad thing. It just shows how much the prior knowledge impacts us as learners. It is something that before I became a teacher, I rarely thought about or even considered in regards to how learning is shaped within us due to experiences and life learning.

  3. 3
    Amanda Duarte on May 20, 2015

    As a teacher of English language learners I find that the most integral part of reading comprehension is whether or not students have the background knowledge necessary to gain meaning from the text. I must ensure I build background for my students in order for them to access the text. We will do topics of study as a whole group in which I read aloud a grade level text and use sentence stems and partner talk to discuss the components of literacy and build background together. This allows my students to access grade level text and use their higher order thinking skills even though they may not have the reading proficiency required to read the text independently. In a small group setting my students are able to read books at their level based on the same topic as the whole group read aloud which builds reading fluency, prosody, and vocabulary. I find that this approach allows me to reach all of the reading levels in my classroom, from those performing many years below grade level to those reading at or above grade level. I find that building background knowledge extends beyond english language arts and is, in fact, essential for academic success in all content areas. For example, once I was going through released testing items to prepare my students for a standardized test. As a teacher of English language learners in a high poverty area I was appalled to see a question asking students to find the area of the granite slab needed to cover the countertop. While I was confident my students had the knowledge to solve an area problem they did not have the background knowledge to know what granite was and let alone understand that it was a material used for countertops. Building students’ backgrounds, especially for linguistically and culturally diverse students, is essential for their academic success!

  4. 4
    Ponderosa on May 22, 2015

    I’ve printed out Literacy Ladders and have begun to read it. Wow! Marilyn Jager Adam’s introduction is a tour de force.

  5. 5
    Tracey Collins on January 22, 2020

    As a reading specialist in a school with many students who come to use lacking background knowledge, vocabulary, and phonological skills, it is easy to pigeon hole them into low-level reading groups. Thank you so much for your piece and your perspective. I plan to share it with my staff as we continue to work to build balance between the shared reading of complex texts in order to build knowledge, language, and vocabulary for all readers. I have found that many teachers have given up the practices of read-alouds or shared reading in favor of all children “independently reading complex text” in order to say they are meeting the standards. The fact is, that if the students can not read the text in front of them, they are not going to be meeting any standards. They are just going to continue to become frustrated and develop a strong dislike for one of my favorite things- reading! Our goal as educators should be to help our students develop love of reading and language and this needs to remain our goal as we build strategic readers.

    I particularly liked your statement “the performance of the poor readers with higher background knowledge is generally better than that of the good readers with less background knowledge, and nearly as good as the good readers with lots of background knowledge.” By scaffolding the actual decoding of the text in a way that supports students and allows them to focus on comprehension and understanding when that is our focus allows them to participate and take part in the learning with their peers. I have seen this in action with some of our lowest level decoders as they are able to listen to a text and then participate with their much more advanced counterparts because they possess a background knowledge and level of language related to the subject that some of their peers do not. What an amazing way to engage our kids in actual interaction with complex text! Thank you for your post.

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