What Is Prior Knowledge
Prior knowledge is everything a reader already knows about a topic, subject, or concept before opening a text. This includes personal experiences, vocabulary, factual information, and conceptual understanding built over years of learning and living. A student reading about photosynthesis brings prior knowledge from science class, garden observations, and conversations. A child reading a story about siblings brings prior knowledge from family dynamics. Without prior knowledge, readers must process nearly every word as new information, which exhausts cognitive resources and tanks comprehension.
Research consistently shows that readers with stronger prior knowledge on a topic comprehend 20 to 30 percent more material than readers starting from scratch. This matters enormously for struggling readers and students with dyslexia, who already expend significant cognitive effort on decoding. When prior knowledge is activated and built intentionally, it reduces the decoding burden and frees mental capacity for understanding meaning.
Prior Knowledge and Reading Instruction
In structured literacy programs like Orton-Gillingham, prior knowledge works alongside explicit phonics instruction. A student learning the /ch/ digraph sound benefits from prior knowledge of words containing that sound (chair, chocolate, chest). Teachers using this approach activate prior knowledge by asking students to name words they already know before introducing the phonetic pattern systematically.
For readers with dyslexia, prior knowledge becomes a compensatory strategy. Because these readers may struggle with phonetic decoding, tapping into what they already know about a topic helps them predict words, confirm meaning, and stay engaged. An IEP (Individualized Education Program) that includes comprehension support should explicitly target prior knowledge activation in lesson planning.
Prior knowledge also determines appropriate reading level placement. A fourth-grader reading at a second-grade decoding level but with strong background knowledge about dinosaurs can often comprehend a dinosaur book above their typical reading level. Conversely, a student at grade level may struggle with a text on unfamiliar topics if prior knowledge is weak.
Building and Activating Prior Knowledge
- Ask direct questions before reading: "What do you already know about farms?" or "Have you ever seen a thunderstorm?" These questions surface relevant knowledge students can connect to the text.
- Use visuals, photographs, or videos to trigger prior knowledge when students lack direct experience with a topic.
- Build vocabulary deliberately before reading. Teaching key words in context activates and expands prior knowledge simultaneously.
- Create opportunities for hands-on experiences or discussions that establish shared prior knowledge in a group or classroom.
- Use schema development strategies to help students organize and link new information to existing knowledge structures.
- Teach explicit prediction strategies that rely on prior knowledge to anticipate what comes next in a text.
When Prior Knowledge Becomes a Barrier
Prior knowledge gaps create real obstacles for struggling readers. A student who has never seen a farm, visited a library, or experienced winter cannot tap into those experiences while reading. Limited vocabulary amplifies the problem. If a reader doesn't know the word "hibernate," they lack the prior knowledge to understand a sentence about bears sleeping through winter.
This is where explicit instruction matters. Rather than assuming students will pick up background knowledge naturally, effective teachers build it systematically. Before a unit on weather, a teacher might discuss types of storms, show photographs, or even create a sensory experience. This scaffolding ensures all students, including those with gaps in prior experience, can access the text meaningfully.
Common Questions
- How do I know if my child's reading struggles are due to weak prior knowledge or decoding problems? A child with strong prior knowledge but weak decoding typically guesses words based on context and initial sounds but struggles with unfamiliar topics. A child with strong decoding but weak prior knowledge reads words accurately but cannot explain what they read. Many struggling readers face both challenges. An evaluation by a reading specialist can clarify which is primary.
- Can I build prior knowledge too much before reading, or will it slow things down? Preparation time should match the difficulty level and unfamiliarity of the text. For a familiar topic, 2 to 3 minutes of activation suffices. For entirely new concepts, 10 to 15 minutes of building background knowledge is reasonable and ultimately saves time by preventing comprehension breakdowns during reading.
- How does prior knowledge connect to activating background knowledge? Prior knowledge is what exists in a reader's mind. Activation is the deliberate instructional act of bringing that knowledge to the surface before reading. You cannot activate knowledge that isn't there, so building prior knowledge through experience and instruction must happen first.
Related Concepts
- Schema refers to the mental framework or network of organized knowledge on a topic that prior knowledge builds and strengthens.
- Activating Background Knowledge is the instructional practice of drawing a reader's prior knowledge into active use before and during reading.
- Prediction relies heavily on prior knowledge to anticipate story events, word meanings, and outcomes based on what readers already understand.