I'm not sure how a reliable updating process would work. You can't keep checking everything you thought you knew in case expert opinion has changed on some of it.
Updates have to use the same channels as new information, and are competing with it.
I'd settle for a reliable method for suspecting that people have just made things up ( maximum heart rate as a simple calculation, that people generally should drink a lot more water than they want, people only use 10% of their brains, Eskimos have a huge number of words for snow, Victorian women had ribs removed to make more extreme corsets possible), but I'm not sure that even that exists.
Common sense works surprisingly well in some cases: even as a child I didn't believe the "10% of your brain" thing... think about it: the only way they could know this is if someone had 90% of their brain removed and wasn't affected... and that doesn't seem nearly as likely as people wanting to believe that everyone has vast untapped potential.
And let's not even get started on how/why evolution would provide us with 10x the brainpower we need... is there any precedent for that in evolution? Can cheetas run 10x faster than they normally do just by trying a little harder? Can seals hold their breath 10x longer than normal?
We're all familiar with false popular memes that spread faster than they can be stomped out: You only use 10% of your brain. Al Gore said he invented the internet. Perhaps it doesn't surprise you that some memes in popular culture can't be killed. But does the same thing happen in science?
Most of you have probably heard of Broca's aphasia and Wernicke's aphasia. Every textbook and every college course on language and the brain describes the connection between damage to these areas, and the speech deficits named after them.
Also, both are probably wrong. Both areas were mistakenly associated with their aphasias because they are near or surrounded by other areas which, when damaged, cause the aphasias. Yet our schools continue teaching the traditional, erroneous story; including a lecture in 9.14 at MIT given in 2005. Both the Wikipedia entry on Wernicke's aphasia and the Wikipedia entry on Broca's aphasia are still in error; the Wikipedia entry on Wernicke's area has got it straight.
Is it because this information is considered unimportant? Hardly; it's probably the only functional association you will find in every course and every book on the brain.
Is it because the information is too new to have penetrated the field? No; see the dates on the references below.
In spite of this failure in education, are the experts thoroughly familiar with this information? Possibly not; this 2006 paper on Broca's area by a renowned expert does not mention it. (In its defense, it references many other studies in which damage to Broca's area is associated with language deficits.)
So:
References
Bogen JE, Bogen GM (1976). Wernicke's region—Where is it? Ann. N. Y. Acad. Sci. 280: 834–43.
Dronkers, N. F., Shapiro, J. K., Redfern, B., & Knight, R. T. (1992). The role of Broca’s area in Broca’s aphasia.
Journal of Clinical and Experimental Neuropsychology, 14, 52–53.
Dronkers NF., Redfern B B., Knight R T. (2000). The neural architecture of language disorders. in Bizzi, Emilio; Gazzaniga, Michael S.. The New cognitive neurosciences (2nd ed.). Cambridge, Mass: MIT Press. pp. 949–58.
Dronkers et al. (2004). Lesion analysis of the brain areas involved in language comprehension. Cognition 92: 145-177.
Mohr, J. P. (1976). Broca’s area and Broca’s aphasia. In H. Whitaker, Studies in neurolinguistics, New York: Academic Press.