In this second-to-last post about John Medina’s Brain Rules, I’m looking at rule 9, “Stimulate more of the senses.”

A good part of this chapter seems intuitively obvious; what caught my eye were things that had been less clear (at least to me).

I’d heard of synesthesia before — the odd sensory-crossing phenomenon in which a person experiences, say, the number 9 as having a flavor. Synesthetes “display unusually advanced memory ability,” Medina says. And they find their apparently odd perceptions to be pleasurable.

Synesthesia suggests that the sensory processes in the brain are designed to work together; the condition simply makes that more striking. But we evolved in a multisensory environment, and so our brains developed ways to effectively process the stimuli coming in from our senses.

Not only do the senses work together, but their combined effects can enhance their individual abilities. In one experiment, people had a hard time seeing a flickering light if its intensity was gradually decreased. Researchers coordinated a short burst of sound with the light flickering off. Subjects who had the sound as part of the experience could see the light beyond their normal threshhold.

Medina cites work by Richard E. Mayer of the University of California Santa Barbara. (He collaborated with Ruth Colvin Clark on E-learning and the Science of Instruction.)

Five of Mayer’s findings:

• The multimedia principle: Students learn better from words and pictures than from words alone.
• The temporal contiguity principle: Students learn better when corresponding works and pictures are presented simultaneously rather than successively.
• The spacial contiguity principle: Students learn better when corresponding words and pictures are presented near to each other rather than far from each other on the page or screen.
• The coherence principle: Students learn better when extraneous material is excluded rather than included.
• The modality principle: Students learn better from animation and narration then from animation and on-screen text.

As Medina points out, these findings home deal with two senses — hearing and vision. Evidence exists that involving the other senses can also enhance learning. Certain types of memory are sensitive to smells, for example. One intriguing example suggests that the sense of smell can improve declarative memory during sleep.

Five senses photo by http://flickr.com/people/joaoloureiro/.