Some people may be smart but readily fall prey to learning things that aren't true. Like that split-infinitive (or more generally split-verb) nonsense -- which is what you get when a bunch of pseudo-intellectuals try to impose a restriction that is inherent in Latin onto English (where it has never belonged) and as a result make beautiful writing ugly. It infects even relatively intelligent people, and Steven Pinker gives a good argument that it may be what made Justice Roberts stumble when administering the presidential oath.
And it's not just language you have to be skeptical about. No less a body than the National Endowment for the Arts writing gushingly about literacy (pdf), fibs to us in graphical form:
Three years at the left hand end takes up almost as much room as six years at the right hand end! The aim is to make the upslope at the end look twice as strong as it really should - to give stronger support to their claim that "this dramatic turnaround shows that the many programs now focused on reading, including our own Big Read, are working". (Lied to by a federal agency? Whodathunkit?) Now if they're willing to fudge the graph, really, how much can you trust that they haven't massaged the figures? Kevin Drum is completely taken in, reproducing the glaring fib with nary an indication he even noticed he was being lied to. There's something about graphical lies that tends to slip under the radar. Watch out!
Over at Understanding Uncertainty, Horace (David Spiegelhalter) looks at studies that say (among other things) that street lighting reduces fatal-injury road crashes by a huge amount. It was taken up by the media, leading to sensationalist headlines. Firstly, based on the quoted figures, the number in the press release was plain wrong (it's 65% not 77%), but various sources of bias lead to this smaller figure being an overestimate, and possibly a very dramatic overestimate. But that won't stop the media in search of a beat-up!
On the topic of things to be skeptical about, the BBC reports that a government-funded books project has edited the famous shanty What Shall We Do With the Drunken Sailor?, though the charity running the project say it has "absolutely nothing to do with political correctness"; they claim the alteration to "grumpy pirate" was to make the rhyme fit a pirate theme, rather than censorship. Now I'm all for pirate themes ... but why then not "drunken pirate"? Is this another media beat-up, or political correctness run amok? Or even a little of both? Go read the story and the explanation given by the charity and decide for yourself. I'd give 'em both a skeptical eye.