BOMBARDED WITH INFORMATION on multiple channels? What do you do? Shut down completely? Or shut out all but one channel of information? Under what conditions can we learn from simultaneous multiple channels? 
Hartman (1961) experimented with multi-channel learning to see when learning took place. He designed his experiments in relation to learning through television, using pictorial and verbal messages. The narration could be spoken or printed.
He identified four possible relationships between sensory inputs: "redundant," "related," "unrelated," and "contradictory."
Hartman found learning took place in the first two relationships, redundant and related. Moreover, he found them superior to single channel learning, because they provided additional cues.

Redundant information is the presentation of the same unit of information at the same time in two channels, such as a word simultaneously spoken and seen as text.

Related information is the presentation of one unit of information as a pictorial representation and the word for the representated unit. Though this method can be highly successful, Hartman cautions that the choice of picture has to be made with care as they may contain other additional cues.

Unrelated information is the simultaneous presentation in multiple channels of unlike units of information, such as a picture of a cat and a number.

Contradictory information is the simultaneous presentation of conflicting units of information in two or more channels, such as the picture of a man, and the spoken word, woman.

Hartman found that in multi-channel presentations no learning took place when there was no relationship between the inputs or the inputs were in fact contradictory.

Pat Griffith
Graduate Student
SDSU Educational Technology