From: jbotz@mtholyoke.edu (Jurgen Botz)
Subject: Mouse-warping considered harmful
Organization: Mount Holyoke College
Date: Fri, 20 Nov 1992 17:27:27 GMT

In article <1992Nov19.202501.14118@medusa.prime.com> gary@CIS.Prime.COM writes:
>In article 1ef01cINNpo4@flop.ENGR.ORST.EDU, atwoodj@CS.ORST.EDU (John Atwood) writes:
> >What's _mouse warping_?
>[...]
>For example, a popup is displayed and you are required to respond by
>pushing a button. The system anticipates your response and moves the
>pointer to the button ready for you to push it.
>
>If the system anticipates correctly, this can be a great help. If not,
>it can easily render a system unusable.

Personally, I hate it even when it /does/ anticipate my response
correctly... in fact, I find it almost painful to have control yanked
out of my hand like that by the system.  It reminds me very much of
the feeling I had when I was learning to fly and the instructor would
'force' my motions via our linked sticks (sure I was glad he was there,
but he was an ungentle man and very impatient, often leaving me with
a very frustrated feeling of having no control over the plane at all.)

Maybe I'm particularly sensitive to relinquishing control, but after
all it /is/ an acknowledged HF principle that as much control as
possible should remain with the user... even if the system is quite
sure it knows what the user wants, it shouldn't do it be taking
control away from the user, but rather it should providing shortcuts
for use at the user's option.

I think that there are a dozen ways of providing the same or similar
levels of convenience for the user as Open Look does when it warps the
mouse to a default response button without violating the principle
that control over the movement of the pointer should remain with the
user at all times.

- Keyboard bindings for default buttons
- Mouse-button bindings for default buttons 
- Gesture-based input (i.e. a little 'check' motion dismisses the
  alert box)
- Alert box positioning (put the button under the pointer rather than
  the pointer over the button, and move the alert with user mouse motion
  until dismissed.)
- When the anticipated response is dismissal, dismiss based on time
  necessary to read
- Non-modal alerts (this is very reasonable if a history of alerts
  is available and notification is prominent enough to ensure that
  the user won't accidentally miss it)
- Alternative input devices
- Voice input
- Default action by inference (if the user does something /other/ than
  respond directly to the alert, assume the default action)

All of these seem reasonable to me, and I'm sure if we tried we could
come up with many more.  Why then did the designers of Open Look feel
that they had to use mouse warping?  Before seeing Open Look I never
even considered this as a UI design idea --- it seemed self-evident
to me that in a direct manipulation interface the device that performs
the manipulation (i.e. the mouse-pointer linkage) should always remain
fully under user control.

Is there anybody out there who can give me a good argument /for/ mouse
warping?  Did the designers of Open Look perform any empirical studies
to test how disruptive/helpful users found mouse-warping to be?  I would
love to see such a study... I'm willing to accept that I might be
relatively unique in being so bothered by this, but until I see some
decent evidence I rather suspect that that's not the case.

  - Jurgen Botz
Newsgroups: comp.human-factors