Intuitive, intuitable, intuition
As always, the subject of 'intuitive' raised its evil little head at the Oxford Politics of Code conference a few days ago. What exactly 'is' 'intuitive', or rather 'intuitable'?

In a paper published in the Communications of the ACM in 1994 (that is, nine years ago) Jef Raskin was quite clear: when it comes to HCI, "Intuitive equals familiar". He discussed the possible intuitable qualities of the computer mouse, and rejected such a supposition. I seem to recall he published a not unsimilar discussion in his book The Humane Interface, following an encounter with a non-user of mice (mouses ;-)). [BTW, the 'Intuitive' paper is also available on Tog's site at http://www.asktog.com/papers/raskinintuit.html .]

But according to one member of staff at Oxford University (on the software side of the house) present at said conference, the computer mouse is completely intuitive (that is, intuitable), but experience is not part of his intuition equation: instinct is. In other words, the mouse arrivses on the desktop fresh from the primaeval forest, part of the basic toolset of hunter-gatherers, ready to be understood by all regardless of background or education....

Intuitive meaning 'instinctive' is clearly different from intuitive meaning 'can be more easily learned based on similar past experiences'. The intuition of software engineers in these matters can clearly paseth all understanding (no, they can never be 'normal users' as in 'find some normal users to test this system on').