How to Use Dual Coding to Improve Memory

Dual coding is a study technique where you combine words with visuals, such as diagrams, sketches, and timelines, so that each idea is stored in two different memory systems instead of one. Two retrieval routes mean a better chance that at least one works when you need the information.

If your notes look like a wall of text, your brain is doing the hard version of studying. Adding a simple drawing next to a definition feels like extra work, but it often pays back many times over at test time. This guide explains the theory, shows what good dual coding looks like, and gives you concrete ways to use it with flashcards.

What Dual Coding Is and Why It Works

Dual coding theory, proposed by psychologist Allan Paivio in the 1970s, says we process verbal information and visual information in two separate but connected systems. When you encode an idea in both, you build two memory traces that reinforce each other.

Think of the idea “photosynthesis.” If you only read the definition, you have one trace: a sentence. If you also sketch a leaf with arrows for sunlight, water, and carbon dioxide going in and oxygen and glucose coming out, you now have a verbal trace and a visual trace. Later, either can trigger the other.

The key terms

Term	Meaning	Study example
Verbal system	Language: words, definitions, explanations	Reading and writing the definition
Imagery system	Visual and spatial information	Drawing or looking at a diagram
Referential connections	Links between the two systems	Labeling a diagram with key terms
Picture superiority effect	Pictures are remembered better than words	Using an icon beside a term

What the Research Says About Its Effectiveness

Studies consistently find that combining words and relevant visuals improves learning compared with words alone, though the effect depends on how well the visuals are designed.

Here are the main findings you can rely on:

• Picture superiority effect. In classic recognition studies by Roger Shepard (1967), participants recognized about 97% of pictures after a single viewing, compared with about 88% of words.
• Multimedia principle. Richard Mayer’s research on multimedia learning found that people learn more deeply from words and pictures than from words alone, with a median effect size of about 1.4 across studies he reviewed. That is considered a large effect in education research.
• Concrete words are easier than abstract words. Paivio’s work showed that concrete, easy-to-picture words are remembered better than abstract ones, because they can be coded in both systems.
• Reviews of learning techniques. The Learning Scientists, a group of cognitive psychologists, list dual coding as one of six evidence-based strategies, alongside spaced practice, retrieval practice, elaboration, interleaving, and concrete examples.

An important caution

Dual coding is not the same as the “learning styles” idea that some people are visual learners and others are verbal learners. Research does not support teaching to one style. Dual coding says that everyone benefits from combining modalities, because it creates richer encoding.

When it doesn’t help

Decoration doesn’t count. Adding a random clip-art picture to a slide can actually increase cognitive load. What matters is that the visual carries meaning about the concept: a process, a structure, a relationship, a sequence.

Creating Diagrams and Visuals Alongside Verbal Notes

Your visuals don’t need to be pretty. They need to show relationships. A messy sketch that you drew yourself will usually serve you better than a polished diagram you copied.

Match the visual to the type of content

If the content is…	Use this visual	Example
A process or sequence	Flowchart or numbered arrows	Steps of the Krebs cycle, stages of a legal case
A hierarchy or classification	Tree or concept map	Taxonomy in biology, types of contracts
Time-based events	Timeline	Causes and events of a historical period
A comparison	Table or Venn diagram	Mitosis vs. meiosis, two economic theories
A structure or anatomy	Labeled sketch	Parts of a cell, layers of the OSI model
Cause and effect	Arrow map or fishbone diagram	Factors leading to inflation
Abstract definitions	Simple icon or metaphor image	A lock for “encryption”

A simple four-step method

1. Read a section and note the key idea in a short sentence. Keep it brief.
2. Sketch the idea. Use boxes, arrows, and a few symbols. Spend two to three minutes at most.
3. Label it with the key terms. This builds the referential links between the two codes.
4. Close the notes and redraw it from memory. This is the retrieval step that turns a nice picture into a durable memory.

Step four is the one most people skip, and it is where much of the benefit comes from. Pairing dual coding with active recall means you’re not only encoding twice, you’re also practicing retrieval.

Use color and position with purpose

• Use color consistently. For example, red for risks, blue for definitions, green for examples. Our guide on color psychology in study notes goes deeper.
• Use spatial position. Put related items close together and keep a consistent layout, so you can later “see” the page in your mind.
• Limit the number of elements. Five to seven items per diagram is easier to remember than fifteen.

Don’t overdo it

A common trap is spending an hour making a beautiful diagram of a topic you’ve barely learned. Beautiful notes are not the goal. If a sketch takes longer than about five minutes, simplify it.

Applying Dual Coding to Flashcard Design

Adding a visual to one side of a flashcard gives you a second retrieval cue and makes abstract facts more concrete. It is one of the easiest ways to upgrade a deck you already have.

Ways to add visuals to flashcards

Technique	How it works	Good for
Image on the question side	Show a diagram and ask “What is this?”	Anatomy, maps, equipment
Image-occlusion	Hide labels on a diagram and recall each	Anatomy, circuits, processes
Image on the answer side	Verbal question, diagram in the answer	Processes, structures
Personal sketch	Draw it yourself and photograph or paste it	Abstract concepts
Icon or emoji cue	Small symbol next to key terms	Vocabulary, definitions
Mini-timeline or table	Insert a simple table in the answer	Comparisons, sequences

Example: a better card

Text-only card

• Front: What are the stages of mitosis?
• Back: Prophase, metaphase, anaphase, telophase.

Dual-coded card

• Front: What happens at each stage of mitosis? (Diagram of a cell with the stages unlabeled)
• Back: The same diagram, labeled, plus a one-line cue: “Chromosomes condense, line up, split, then separate into two nuclei.”

The second card forces you to retrieve the sequence, the visual form of each stage, and the verbal labels, which is much closer to what an exam might ask.

Rules of thumb for visual cards

1. One concept per card. Don’t paste a whole textbook figure with 20 labels.
2. Cut extra details. Remove anything that isn’t needed to answer the question.
3. Keep the question clear. The image should support the question, not replace it.
4. Use your own images when you can. The act of creating them is itself learning.
5. Review on a schedule. A visual card still fades without spaced repetition.

Tools that help

You can build visual cards manually in any flashcard app. If you’d rather save time on the card creation itself, LongTerMemory can generate question and answer pairs from your PDFs and lecture notes and handle the review scheduling, so you can spend your effort on the part that matters most: sketching and adding the visuals that make key ideas click. For a deeper look at building better decks, see our guide to turning PDFs into flashcards.

Dual Coding by Subject: Practical Examples

Subject	Verbal element	Visual element
Biology	Definitions of organelles	Labeled cell diagram
History	Causes of a war	Timeline plus cause-effect arrows
Law	Elements of negligence	Flowchart: duty, breach, causation, damages
Medicine	Drug mechanism	Pathway sketch with the drug’s action marked
Programming	How recursion works	Call stack diagram
Economics	Supply and demand	Curve graph with shifts labeled
Languages	A vocabulary word	Picture or scene representing it

Notice how each pair describes the same concept through two different routes. That redundancy is the feature.

Common Mistakes to Avoid

1. Decorating instead of explaining. Visuals must show structure, process, or relationships.
2. Copying instead of creating. Tracing a textbook figure is passive. Redraw it from memory.
3. Overloading the visual. Too many labels or colors create noise.
4. Reading the text and looking at the diagram at the same time without thinking. Actively link them. Ask yourself what each arrow means.
5. Treating it as a learning-styles fix. It is for everyone, and it’s most useful when combined with retrieval practice and spacing.
6. Skipping review. A visual doesn’t make a memory permanent. Revisit it over days and weeks.

A 20-Minute Dual Coding Routine

Minutes	Step	What you do
0 to 5	Read	Read one section, highlight only key ideas
5 to 10	Sketch	Draw one diagram that shows the main structure or process
10 to 15	Retrieve	Cover the notes and redraw it from memory
15 to 18	Fix	Compare, correct, and add what you missed
18 to 20	Card	Turn the diagram into one visual flashcard

Repeat this once or twice per study session. Over a week, you’ll build a small library of visuals and cards that are highly personal and easy to review.

Frequently Asked Questions

What is dual coding in simple terms?

It means learning something with both words and pictures so that you store it in two ways in your brain. If you forget one, the other can help you recall it.

Do I need to be good at drawing?

No. Stick figures, boxes, arrows, and simple icons are enough. The goal is to show relationships, not to make art.

Is dual coding the same as learning styles?

No. Learning styles claim people learn best in one modality, and that claim lacks evidence. Dual coding says that combining modalities helps everyone.

Does dual coding work for abstract subjects?

Yes, but you need to find a visual structure: a flowchart for an argument, a map of relationships between concepts, or a metaphor image. It takes more thought, which itself helps learning.

How often should I review dual-coded notes?

Use spaced repetition: after a day, a few days, a week, and then a few weeks. Each review should involve retrieval, not just looking.

The Bottom Line

Dual coding works because it gives you two ways to get to the same idea. Pair every key concept with a simple, meaningful visual, redraw it from memory, and put the best ones into your flashcards.

Try it with just one topic today: take the page you’re studying, draw a five-minute diagram, then redraw it without looking. If it feels harder than rereading, good. That difficulty is the sign that you’re building memory, not just recognizing it.