The Modality Principle
People learn more deeply from a multimedia message when the words are spoken rather than printed.
The rationale is that the modality principle allows learners to off-load some of the processing in the
visual channel (i.e., the printed captions) onto the verbal channel, thereby freeing more capacity in the
visual channel for processing the animation. This principle was supported in 53 out of 61 experimental
tests, yielding a median effect size of 0.76. For example, Moreno and Mayer (1999) found that students
performed better on a transfer test after receiving a narrated animation on lightning formation than
after receiving the same animation with on-screen captions that contained the same words as the
narration. Similar results are reported in a meta-analysis by Ginns (2005). As the most studied principle
in the list, research shows that the modality principle should not be taken to mean that spoken words
are better than printed words in all situations. Some important boundary conditions reported in some
studies are that printed word may be effective when the verbal material contains technical terms, is in
the learner’s second language, or is presented in segments that are too large to be held in the learner’s
working memory (Mayer, 2009; Mayer & Pilegard, in press).