From: barmar@think.com (Barry Margolin)
Newsgroups: alt.religion.computers,comp.windows.misc,comp.windows.news,comp.windows.x,comp.human-factors
Subject: Re: GUIs Considered Harmful
Date: 3 Sep 1992 18:44:41 GMT
Organization: Thinking Machines Corporation, Cambridge MA, USA
NNTP-Posting-Host: telecaster.think.com

In article <NEERI.92Sep3175345@iis.ethz.ch> neeri@iis.ethz.ch (Matthias Neeracher) writes:
>Maybe I misinterpreted your expression "key sequence to get to menubar". What I
>thought of is you press a key, the first menu falls down, and you maneuver your
>way to the desired menu entry using the cursor keys.

Consider the Motif style of menu accelerators.  Each menu has an associated
key (e.g. "F" for the "File" menu), and then a second key selects an option
within that menu.  Thus, Control-F O might be the accelerator for "Open..."
(the Control modifier is necessary to distinguish accelerators from
ordinary text being entered in the window).  By organizing the accelerators
both mnemonically and hierarchically similarly to the menus, the transition
is simplified.

>  People new to the mouse find the process of reaching for it every time they
>  want to do anything other than type to be incredibly time-wasting. And
>  therein lies the very advantage of the mouse: It is boring to find it
>  because the two-second search does not require high-level cognitive
>  engagement.
>
>  It takes two seconds to decide upon which special-function key to press.
>  Deciding among abstract symbols is a high-level cognitive function. Not only
>  is this decision not boring, the user actually experiences amnesia! *Real*
>  amnesia! The time-slice spent making the decision simply ceases to exist.

While I agree that the time taken reaching for the mouse is lost, I
personally find the process of selecting an item from a menu just as
challenging as remembering the keyboard sequence.  The precise positioning
necessary to select just the right menu item is a complex motor task.

Did the study differentiate between users who touch type and those who
don't?  For non-touch typists, I suspect that much of that cognitive
process is simply searching for the key.

Also, I presume that the above results are mainly for infrequent
operations.  Imagine a text editor where incremental cursor motion was
performed by selecting "Next Line" and "Previous Line" commands from a
menu, compared with one using arrow keys, Emacs-style control keys, or
vi-style keys (although I suppose Open Look's pinnable menus and the Mac's
tear-off menus can make sequential repetition of these from a menu as easy
as the keyboard versions).

Another factor, I presume, is consistency.  The process of selecting a menu
item is consistent across most Mac applications, so that task soon becomes
automatic and non-cognitive.  In the case of keyboard accelerators, most of
them are ideosyncratic to the application, so it is hard for them to become
automatic unless the user only uses that one application.  Conversely,
those functions whose shortcuts have become standardized become less
cognitive; I suspect many (but not most) Mac users who don't normally use
shortcuts still use the keyboard equivalents to Cut, Copy, Paste, and Quit,
since these are the same in just about every application defines these the
same way.

>  Hence, users acheive a significant productivity increase with the mouse in
>  spite of their subjective experience.

This reminds me of an article I read years ago (in "Technology Review", I
think) about subjective experiences when waiting.  One of their findings,
and I see the same behavior in myself, is that car drivers will often take
a longer route in order to avoid traffic lights, even though the added
driving time is less than the usual waiting time.

The issue for user interface designers is what they should be optimizing:
absolute productivity or user satisfaction.  If a user is 10% more
productive but enjoys the process 20% less, is that a good tradeoff?
-- 
Barry Margolin
System Manager, Thinking Machines Corp.

barmar@think.com          {uunet,harvard}!think!barmar
Newsgroups: alt.religion.computers