Really good post by Clive Shepherd summarising a talk by cognitive neuroscientist Dr Itiel Dror that Clive attended . The key point for me, in Clive's summary, is:
"The brain is a machine with limited resources for processing the enormous quantity of information received by the senses. As a result, attention is extremely selective and the brain must rely on all sorts of shortcuts if it is to cope effectively."
This squares with one of the main theses of "The user illusion, cutting consciousness down to size" by Tor Nørretranders a book that influenced me a lot, and that I wish more multimedia designers had read. More about the nature of consciousness than about learning, it provides convincing evidence that the conscious mind is only able to deal with a tiny proportion of the data it receives - perhaps as little as 30 bits per second. The mind then creates a "media-rich" consciousness from this thin data-stream. We've evolved to interpret the sensually complex real world in an effective way; but that does not mean that our brains are good at interpreting media-rich learning materials, which should hence be used (if used) with great care. As Clive summarises:
"Teachers/designers can adopt two strategies to reduce the risk of learners experiencing cognitive overload: provide less information (quantitative approach) or take much more care about how this information is communicated (qualitative approach)."