There is too much to recount here withotu simply reproducing Clive's articles but to give you a flavour of the 28 learning points:

• 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.
• 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).
• To reduce cognitive overload, take out every word or picture that is not necessary or relevant to your learning goals. Even then, don't deliver more than the learner can handle
• The brain continues to change throughout our lives, even though we stop adding new brain cells in our early 20s. Some parts of the brain are relatively hard-wired (through nature or nurture), some very plastic. It makes sense to concentrate in recruitment on finding those people with hard wiring which suits the job, because no amount of training will sort the problem out later. (Itiel did not go into detail about those capabilities which tend to be hard-wired and those which are more plastic - this is clearly important.)
• As you grow older the hard-wired capabilities persist - the most learnable capabilities go first.
• Working memory consists of 7+/-2 items

Stephen Downes has written a response to this outlining those areas where he agrees and those where very much disagrees! He usefully outlines the importance of patterns. "We can remember things that are more than 7 words long by recognizing them as coherent patterns. What we put into working memory first depends on pattern recognition."

All instructional designers will be interested in the debate and the relevance to learning design. 

You can read Clive's orginal piece at

http://clive-shepherd.blogspot.com/2007/02/science-of-learning.html 

and Stephen's response at

http://halfanhour.blogspot.com/2007/02/science-of-learning.html