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Re: German tutorial fix

From: Miles Bader
Subject: Re: German tutorial fix
Date: 20 May 2002 01:10:58 +0900

Alex Schroeder <address@hidden> writes:
> I bet it also depends on keyboard layout and customizations outside of
> Emacs.

Well of course, but emacs' entire command set is predicated on certain
constraints, like the control key being easy to type.

> Skimming the TOC and checking some chapters selectively, I think here
> is what he might say:

[I know I shouldn't reply to this, because it's really beside the point,
but well...]

> 1. Habit formation -- sometimes you use the arrow keys, sometimes C-f
>    to move point.  That is bad for habit formation.

That is no doubt true.  However, the claim made was not that the
control-keys are _easier_ to learn (they clearly are not, if the user
already knows about arrow keys), but that they are more efficient to use.

There's also an argument that the habits we want people to form are in
fact the control-key methods of doing stuff.

> 2. GOMS keystroke level model -- arrow keys might involve hand
>    movement similar to moving from the keyboard to the mouse, thus you
>    have one H element in the analysis, and a K for the press, and
>    mentally preparing M.  C-f has mentally preparing, and two
>    keypresses.  The timing he gives for the simplified analysis would
>    be M = 1.35s, K = 0.2s, H = 0.2s, thus the two are exactly
>    equivalent as far as the GOMS model is concerned.

Hmmm, that would be a good clue that the GOMS model (whatever that is)
has a flaw.  Moving your hands from the home row to the arrow keys (and
back again) is _very_ costly on most PC keyboards -- not only is the
actual movement expensive, but (1) quite often you have to adjust your
body position to accomodate the arm movement [they're _that_ far away],
and (2) you screw up the positioning of your hands on the home row
(which doesn't happen at all with the control-key cursor movement keys;
they're in fact almost exactly like typing).

Thus, if I understand what you wrote above, he's seriously underestimating
H.  I would also suggest that he's _overestimating_ M in many cases -- the
sort of simple editing commands that often happen while typing in text are
not the sort of thing you actually think about, they're almost automatic.

I don't doubt that he's based the above numbers on actual measurements,
although such things are almost certainly highly dependendent on who's
being measured.

> 3. Hick's Law -- since you now have two equivalent methods of moving
>    point, this not only hampers habit formation, it also imposes a
>    cognitive burden when you have to choose between the two.

See point 1.

In any case, everything is a tradeoff -- while having many arbitrary and
capricious methods of performing every command is certainly confusing, in
some cases the benefits outweigh the problems.  In the current case, we're
talking about probably the _most used_ commands in emacs (well, actually I
suppose that would be `self-insert-command' :-), which is exactly the case
where one wants to think about efficiency, even if it takes a slight bit
of extra work by the user to remember.

[after all, if we really took this `Law' seriously, we'd have to get rid
of the keybindings, and M-x, and just use the menus for everything...]

> My claim is just that 1. C-f is not obviously better, and 2. conflicting
> opinions exist.  So why use it as an argument, if we have far better
> arguments at hand?  For example stupid terminals.

The danger is that people will read such this and say `I have arrow keys,
so I don't need to bother with all these strange and odd key-bindings --
they're only for sad users stuck on 1970's hardware.'

If we believe (as I obviously do) that the non-arrow-key bindings are
_better_ in some situations, and also offer other less tangible benefits
(such as their integration into the emacs `scheme' for keybindings), then
we really ought to also point out `Hey, these bindings may seem
unnecessary, but really, you ought to try them for a while, you may be
glad you did.'

Even if they later decide that they really rather prefer the arrow keys,
just having some experience with the traditional cursor-movement keys will
probably aid them in understanding other emacs' keybindings, and may make
learning emacs easier in general.

> I have it, RMS had it, iirc, Ben Wing had it, JWZ had it, James
> Gosling had it, ... health might be just as important as typing speed.

Sure, but I suspect that most of the emacs command set is toast if you
really care to avoid RSI (and are arrow keys really any better, other than
by slowing you down?  They require hand movement and keypressing, just
like any other key...).

Somebody has to do something, and it's just incredibly pathetic that it
has to be us.  -- Jerry Garcia

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