A fascinating new open access article, The Myth of Cognitive Decline: Non-Linear Dynamics of Lifelong Learning. It gets a little dense between the abstract and the conclusion, but basically finds…

“… that older adults’ changing performance reflects memory search demands, which escalate as experience grows. … Our results indicate that older adults’ performance on cognitive tests reflects the predictable consequences of learning on information-processing, and not cognitive decline.”

So you may slow down a little, but any slowness is because there’s so much in your mind to sort through. In that case the “outboard memory bank” function of frequent blogging / Instapaper archiving / vast date-ordered digicam archives etc looks like a winning strategy, as the baby boom generation starts to head into old age.