[ACT-R-users] PM-Question

[Dan Bothell]

--On Friday, October 11, 2002 3:21 PM +0200 Wolfgang Schoppek 
<Wolfgang.Schoppek at uni-bayreuth.de> wrote:

> So my question has changed: What's the best way of making an ACT-R/PM model
> recognize that the state of the world has changed?

That's what buffer stuffing is for.  The mechanism is described in the 
tutorial in unit 3 (section 3.4 introduces it with respect to the 
aural-location buffer) and unit 4 (section 4.2.1 describes its use with the 
visual-location buffer) and the demo model for unit 4 uses it to detect screen 
changes.  The basic mechanism is if a *-location buffer is empty when a change 
occurs and there is an object after the change that matches the specification 
to be stuffed then that objects location is placed into the corresponding 
location buffer.  To use it, when you are "waiting" for a change you clear the 
*-location buffer.  Then the production that you want to fire after the change 
includes a test on there being something in that buffer, thus it can't fire 
until after the stuff occurs.

Dan