A Dual Coding View of Vocabulary Learning
Sadoski, M. (2005). A dual coding view of vocabulary learning. Reading & Writing Quarterly, 21(3), 221–238. doi:10.1080/10573560590949359
Abstract
A theoretical perspective on acquiring sight vocabulary and developing meaningful vocabulary is presented. Dual Coding Theory assumes that cognition occurs in two independent but connected codes: a verbal code for language and a nonverbal code for mental imagery. The mixed research literature on using pictures in teaching sight vocabulary is briefly reviewed, and a possible resolution suggested. The use of concrete, high-imagery words and both verbal and nonverbal contexts are found to be important factors in teaching sight vocabulary along with word decodability. Effective methods of teaching meaningful vocabulary that are consistent with Dual Coding Theory are briefly reviewed, including self-generated imagery, the use of illustrations, the keyword method, and verbal-associative methods. Results are relevant for both normal readers and those experiencing reading problems.
Authors
- Mark Sadoski1
How Our Brains Learn Words: What Science Reveals About Vocabulary Instruction
Have you ever wondered why some words stick in your memory while others slip away? Or why a picture is sometimes worth a thousand words when you're trying to learn something new? A research paper by Mark Sadoski tackles these questions by exploring how our brains actually learn vocabulary—and the findings have surprising implications for how we teach reading and language.
The core question driving this research is deceptively simple: what's the best way to help people, especially children, learn new words? You might assume that simply looking up a definition or reading a word in context would be enough. But decades of cognitive science suggests something more interesting is happening inside our heads when we learn vocabulary. Sadoski approaches this through Dual Coding Theory, a framework suggesting that our brains process information in two distinct ways: through language (the verbal code) and through mental imagery and real-world knowledge (the nonverbal code). The theory predicts that when both systems work together, learning becomes more powerful.
To test this theory, researchers conducted numerous experiments comparing different vocabulary teaching methods. Some studies tracked children learning sight words—the basic vocabulary we recognize instantly when reading. Others tested how well adults could retain new words using various instructional techniques. The experiments varied what information was presented: definitions alone, definitions plus sentences, definitions plus sentences plus pictures. Some studies even compared exotic techniques like the "keyword method," where learners create vivid mental images linking new words to similar-sounding familiar words.
The results were remarkably consistent across studies and age groups. Here's what emerged:
- Concrete words beat abstract words by a significant margin. When learning by sight, children required about 12 percent fewer exposures to learn concrete words (like "cat" or "jump") compared to abstract words (like "truth" or "justice"). First graders showed even more dramatic differences—taking roughly 60 percent more trials to learn abstract words.
- Pictures and imagery matter tremendously. When students learned definitions paired with illustrations, their retention improved substantially, especially on delayed tests weeks later. One study found that undergraduates learning 50 new words showed significantly better retention when they received definitions, example sentences, *and* pictures, compared to any of these elements alone.
- Graphic organizers enhance semantic learning. Showing how related words connect—through diagrams that display vocabulary hierarchically—proved highly effective, particularly after reading. This bridges the gap between simply knowing words and actually understanding how they relate to one another.
- Morphological analysis works. Teaching students to break down unfamiliar words into components like roots and prefixes, then recombine them into meaningful wholes, nearly doubled their understanding of affixed words. Research across multiple studies confirmed this approach helped students not just learn target words but transfer that knowledge to entirely new words they'd never encountered.
Why should any of this matter to someone outside academia? Consider the practical implications: if teachers and educational designers understand how brains genuinely learn words, they can create more efficient, effective instruction. A struggling reader who learns that "un-" means "not" doesn't just memorize one word—they gain a tool for understanding thousands of related words. A student who sees a picture alongside a definition isn't just getting redundant information; they're engaging both the visual and verbal parts of their brain, creating stronger, more retrievable memories.
There's also a deeper implication embedded in these findings: concrete knowledge forms the foundation for abstract thinking. Since concrete words involve both language and mental imagery—because we can actually visualize a cat or a tree—they're neurologically easier to learn. Abstract words rely primarily on language and must be connected to other abstract concepts, making them harder to grasp, especially for younger learners. This suggests that moving students toward more sophisticated, abstract vocabulary requires first building strong concrete foundations.
The research also reveals that vocabulary instruction isn't one-size-fits-all. A struggling reader benefits differently from a strong one. A second grader processes words differently than an adult. Yet the underlying principle holds: engaging multiple mental systems—combining words, images, and meaningful connections—consistently outperforms any single approach.
What makes this body of research particularly valuable is its accumulation across decades and contexts. Individual studies can be questioned or replicated, but when researchers using different methods with different age groups in different settings all reach similar conclusions, we gain confidence in the underlying truth. The consistent finding that concrete words are learned more easily, that pictures enhance retention, and that teaching word structure improves learning suggests these aren't quirks of a particular study but fundamental features of how human cognition works.
For parents, teachers, and anyone involved in education, the takeaway is clear: when teaching vocabulary, activate as many mental systems as possible. Don't just give definitions—provide context, use images, explore word roots, and encourage mental visualization. The science suggests your brain was built to learn language through multiple channels simultaneously, and the most powerful teaching acknowledges that reality.
This summary was generated by AI and may contain errors. Always refer to the original paper for accuracy.