What did Cuevas & Dawson (2018) find about processing words plus imagery?

Retention roughly DOUBLED when learners processed both words and imagery — for ALL participants, regardless of whether they called themselves "visual" or "auditory" learners.

Cuevas & Dawson (2018) compared learning with a single mode against learning that combined verbal and visual processing. The dual approach roughly doubled retention — and crucially, the benefit did not depend on a person's self-described "learning style." Everyone gained.

That last part is the knockout: the boost comes from the material being encoded two ways, not from matching a person's preference. It's evidence for dual coding and against learning styles in a single study.