Principle	Category	Description
Coherence effect	Reduction of extraneous load	The material presented to the student should avoid including information that is not part of the contents being studied.
Signalling effect		A presentation should give clues to students to guide their attention towards main points, by emphasizing or repeating information.
Redundancy effect		Narrated text should not be accompanied of written text, since this can distract students from observing pictorial information.
Spatial contiguity effect		The close placement between texts and pictures reduces the effort of students to inspect material and favours learning.
Temporal contiguity effect		The presentation of verbal and non-verbal pieces of information should occur simultaneously instead of sequentially.
Segmenting effect	Management of essential processing	The presentation of information should use separable units whenever possible, instead of fusing several concepts into complex texts and pictures.
Pre-training effect		Introductory material in the beginning of a presentation, may reduce the cognitive load associated to complex information that forms the core of the learning material.
Modality effect		When pictorial and verbal information are combined, the use of narrated (spoken) text is preferable over written text.
Multimedia effect	Fostering generative processing	Explanations with text and pictures are more efficient than those presenting information using only one of these possibilities.
Personalization effect	Fostering generative processing	The presentation of material should preferably make students feel part of the narration, for example using second person instead of third person conjugation.