Evidence for Dual coding: words and pictures together #

Every substantive claim on the Dual coding: words and pictures together page is checked against current research. Here is each claim, how well today’s evidence supports it, and the sources. The full, de-duplicated source list lives on the references page.

Supported · moderate evidence — Information is processed and stored through two partly independent systems — a verbal channel for words and a non-verbal channel for imagery (dual-coding theory).

Dual-coding theory remains a foundational and broadly accepted account of memory in cognitive psychology; the two-channel architecture (verbal and visual/spatial working memory) is consistent with Baddeley’s working-memory model and is reflected in current cognitive-load and multimedia-learning frameworks.

Sources: Paivio, A. (1986), Mental Representations: A Dual Coding Approach — Oxford University Press · Clark, J. M., & Paivio, A. (1991), Dual coding theory and education, Educational Psychology Review 3(3), 149-210 · full reference ›

Supported · moderate evidence — Encoding an idea in both the verbal and imagery channels creates two retrieval routes, making it more memorable than encoding it in one channel alone.

The additive-trace prediction of dual coding is well supported by picture-superiority and the benefit of imagery-plus-verbal encoding over verbal-only encoding in recall experiments.

Sources: Paivio, A., & Csapo, K. (1973), Picture superiority in free recall: Imagery or dual coding?, Cognitive Psychology 5(2), 176-206 · Paivio, A. (1986), Mental Representations: A Dual Coding Approach — Oxford University Press · full reference ›

Supported · strong evidence — Concrete words (e.g. ‘bicycle’) are remembered better than abstract words (e.g. ‘justice’) because concrete words evoke a mental image and are coded in both channels.

The concreteness/imageability effect on memory is one of the most robustly replicated findings in verbal-memory research and is well explained by dual coding.

Sources: Paivio, A. (1986), Mental Representations: A Dual Coding Approach — Oxford University Press · Paivio, A., Yuille, J. C., & Madigan, S. A. (1968), Concreteness, imagery, and meaningfulness values for 925 nouns, Journal of Experimental Psychology 76(1, Pt.2), 1-25 · full reference ›

Supported · strong evidence — People learn more deeply from words and pictures together than from words alone (the multimedia principle).

The multimedia principle is supported by a large body of controlled experiments and multiple meta-analyses showing a consistent positive effect of adding relevant graphics to text or narration.

Sources: Mayer, R. E. (2021), Multimedia Learning, 3rd ed. — Cambridge University Press · Mayer, R. E., & Fiorella, L. (2022), The Cambridge Handbook of Multimedia Learning, 3rd ed. — Cambridge University Press · full reference ›

Supported · strong evidence — Visuals help learning when they convey information (structure, process, spatial relations) but adding purely decorative images does not aid, and can distract from, learning.

Mayer’s coherence principle — that extraneous, decorative (‘seductive’) material depresses learning — is well replicated; instructional benefit comes from explanatory rather than decorative graphics.

Sources: Mayer, R. E. (2021), Multimedia Learning, 3rd ed. — Cambridge University Press · Sundararajan, N., & Adesope, O. (2020), Keep it coherent: A meta-analysis of the seductive details effect, Educational Psychology Review 32, 707-734 · full reference ›

Supported · moderate evidence — Presenting the same words simultaneously as on-screen text and as narration (redundancy) harms learning rather than helping it.

The redundancy effect is well established for the canonical case of identical on-screen text duplicating narration alongside graphics; effects are moderated by pacing and text length, but the principle holds for simultaneous verbatim redundancy.

Sources: Mayer, R. E. (2021), Multimedia Learning, 3rd ed. — Cambridge University Press · Kalyuga, S., & Sweller, J. (2014), The redundancy principle in multimedia learning, in The Cambridge Handbook of Multimedia Learning · full reference ›

Supported · strong evidence — Placing related words and pictures near each other in space (and time) improves learning compared with separating them (the contiguity principle).

Spatial and temporal contiguity effects are among the most consistently replicated multimedia-design findings, explained by reduced extraneous load from not having to visually search and hold items in working memory.

Sources: Mayer, R. E. (2021), Multimedia Learning, 3rd ed. — Cambridge University Press · Schroeder, N. L., & Cenkci, A. T. (2018), Spatial contiguity and learning: A meta-analysis, Educational Psychology Review 30, 679-701 · full reference ›

Supported · moderate evidence — Each processing channel has limited capacity, so redundant or extraneous material overloads the channel it was meant to support.

Limited working-memory capacity per channel is a core, well-supported assumption shared by cognitive load theory and the cognitive theory of multimedia learning, building on Baddeley’s working-memory research.

Sources: Mayer, R. E. (2021), Multimedia Learning, 3rd ed. — Cambridge University Press · Sweller, J., van Merrienboer, J. J. G., & Paas, F. (2019), Cognitive architecture and instructional design: 20 years later, Educational Psychology Review 31, 261-292 · full reference ›

Supported · moderate evidence — Reciting the same words aloud while reading them engages only the verbal channel and is not dual coding; pairing words with a picture is needed to gain the dual-channel benefit.

Follows directly from dual-coding theory: the memory advantage comes from coding across the verbal and imagery systems, not from duplicating material within the verbal system; consistent with picture-superiority and imagery-encoding evidence.

Sources: Paivio, A. (1986), Mental Representations: A Dual Coding Approach — Oxford University Press · Paivio, A., & Csapo, K. (1973), Picture superiority in free recall: Imagery or dual coding?, Cognitive Psychology 5(2), 176-206 · full reference ›