"More people have written about this than I have." It's interesting, as Geoff Pullum observes, that such sentences go down so easy, since they're completely incoherent.
These sentences remind me of the pictures of stairways that spiral up endlessly within a finite space, and the Shepard tones whose pitch seems to go up and up without ever getting any higher. All these stimuli involve familiar and coherent local cues whose global integration is contradictory or impossible. These stimuli also all seem OK in the absence of scrutiny. Casual, unreflective uptake has no real problem with them; you need to pay attention and think about them a bit before you notice that something is going seriously wrong.
Like Escher stairways and Shepard tones, these sentences are telling us something about the nature of perception. Whether we're seeing a scene, hearing a sound or assimilating a sentence, there are automatic processes that happen effortlessly whenever we come across the right kind of stuff, and then there are kinds of analysis that involve more effort and more explicit scrutiny. This is probably not a qualitative distinction between perception and interpretation, but rather a gradation of processes from those that are faster, more automatic and less accessible to consciousness, towards those that are slower, more effortful, more conscious and more optional.
Posted by Mark Liberman at May 7, 2004 02:49 PM