Knowledge in the fingertips

My new job means I have to use Delphi.  I've used Visual Studio and its precursors since Visual Basic 1, so adapting to Delphi has been a painful experience.  My fingers know that F5 means debug and F9 means breakpoint, and no amount of knowledge in the head will convince them it's the other way round.

I thought this was down to my fingertips having ten years of usage drummed into them, but now I think they're a lot more fickle than that.  After just a week and a half of using Delphi every day, I turned back to Visual Studio.NET, and my fingers instinctively stabbed at the Delphi keys.  Worse still, even though I knew I was writing in C#, when I came to common constructs, my fingers started typing in Pascal.  (Needless to say, at work they still insist on typing in C#, curse them.)

On the other hand, as long as knowledge in the fingertips still works, it takes a long, long time to die.  Windows has used sensible Mac-style keystrokes for Cut, Copy and Paste since 3.1, but when I need to copy and paste, my fingers still reach for the cryptic and contortionist CUA combinations.  Believe me, I couldn't even tell you for certain what the CUA keystrokes are, except that they involve various combinations of Ins and Del.  The head doesn't know.  But the fingertips do.  So I still use them, and expect to carry on using them until the Standardisation Fairies finally take them away to Sleepytown.

What does this mean for user interface designers?  First, consistency is relative.  People who use different applications in different ways have different knowledge in their fingertips.  In particular, people who already use your application may have very strong subconscious expectations of how a new version will behave.  Second, being consistent enough to let the fingertips work their magic really does make a big difference in those critical first two weeks.  But third, forget about two weeks: even ten years is not enough for migrating really common UI idioms.  If your users use a feature several times a day, they will never move over to your new design until you get rid of the old one.  Either you have to support their old UI for ever, or at some point their fingertips have got to take the pain.

The fingertips are powerful.  In the short term, the fingertips always win.  If you ask your focus groups, you'll probably find the fingertips telling you to keep things the same.

But, in the long term, fingertips are fickle.  Give them two weeks, and they'll have settled into the new idiom and will find it hard to go back.  In fact, if they're using a feature intensively enough, it can take just hours for knowledge to migrate off the screen, into the head and down the arms.  The most painful adjustments can, in the end, be the fastest and easiest.