Competing "retrieval" rule vs compiled "habit" rule?

[Hedderik van Rijn]

> I have what I think is a technical "how to" query about ACT-R, although 
> it
> sometimes turns out that what I think are "how to" issues are really 
> deep

Although I never modeled a task like you described, I've done some work 
both on interpretative rules vs proceduralized rules and on two 
interfering tasks, both in 5.0. So, I'll just report what my ideas were 
while reading your example of getting bread while driving home.

The major change from 4 to 5 with respect to the buffers might be useful 
in this example. Although I'm not really into the motor and perceptual 
stuff, so I'll probably violate some ideas about these, the new buffer 
structure might be able to help.

1. proceduralized rules do the driving. They tell the motor-system to do 
its driving job. The motor-system does its driving, and reports back any 
abnormalities in the motor-buffer.
2. proceduralized rules do the perception. As soon as something enters 
the perceptual buffer, they take care of it. I.e., tell the motor-system 
to stop for that old lady that wants to cross the street.
3. interpretative rules check the retrieval buffer, if anything is 
available there, then process that chunk.

Now, if the 1 and 2 rules are rather generic (i.e., either have a 
generic goal if that still exists, or all the goals in the system are of 
the same chunk-type, as in some of Niels' proceduralization models), 
they can always interfere. Because being proceduralized and often 
successfully used, they have a high utility, and will therefore 
(luckily, as I'd rather not miss that large truck that suddenly comes to 
a stop) interfere any process based on more costly or less successful 
interpretative rules.

However, if nothing is available in the motor and perception buffers, 
the system is free to donate some time to the important task of not 
forgetting to buy bread. (Note that in 5 the model initiates a 
retrieval, and is then free to do whatever it want... it doesn't lock up 
until the chunk is actually retrieved.)

But, if involved in a conversation (i.e., buffers are filled with other 
information than "getting bread") or a lot of things are happing on the 
road (i.e., the proceduralized rules do not allow the interpretative 
rule to fire), the "remember to get some bread" chunks will likely not 
be retrieved until parking the car at home.

> rule on the grounds of their respective statistical histories -- it 
> seems
> like comparing chalk and cheese.

Which, in some countries, is not too ridiculous...

   Hedderik.