how can ACT-R models age?

[Mark Dekker]

ram>Very interesting discussion, Dario and respondents!

After the 'a bit late' responses now 'a very late' respons. Maybe this is =
a  
open door I am kicking in, but for me this issue is not so clear yet. 


I think that when comparing age groups and manipulating a model of a 
=91task A=92 to it accordingly, those  manipulations should be theoretical=
ly 
plausible in there representation of what happens in consequence of 
aging. So now the assumption is made about how aging is represented in 
the model. When subsequently (the same) age groups are topic in the 
modeling on another =91task B=92, we should use those manipulations of 
which it was earlier assumed to represent the age difference. If we were 
correct, in this way we should be able to capture the age differences or 
similarities in behavior this task. 

I think this idea relates in general way to the work on individual 
differences done by Marsha, Christian, Larry Daily and Lynne Reder, in 
the sense that the modeling of one task is being used to explain or even 
predict the data on another task. 


My question would be:

Is it possible to capture by this approach (by means changes of 
parameter settings) the more strategic differences that are found in 
behavior between different age groups? 

A recent example of these qualitative/strategic differences has been 
found (Nieuwenhuis etal 2000 in Psychology and Aging, vol. 15(4)) in 
using a antisaccade task.  Elderly compared to younger adults were 
found to rely more on external cues when the task at hand provides that 
possibility (in contrast to a endogenous manner of control which is 
another possibility to rely on). But when  the possibility to rely on 
external cues is removed, the voluntary endogenous manner of control 
now is being used consistently by the elderly. 

Altough this maybe is not the most hard finding, other studies have 
showed qualitative differences also. This paper is, though, also 
interesting with respect to the issue of inhibition and aging which 
popped up. A more general discussion about this in  Journals of 
Gerontology: Series B (1997, vol.52B(6)) in papers by McDowd, by Burke 
and by Zacks&Hasher.


The idea that aging groups can differ in how a task is performed is in my 
opinion also reinforced by neuroimaging studies that find differences 
between age groups in patterns of activation when performing working 
memory tasks.

Again, I wonder whether manipulating the continuous parameters can 
result qualitative/strategic differences which are found between age 
groups. Naturally this question not only applies to aging but also to 
other sources of inter-individual differences and intra-individual 
differences (eg fatigue) as Dario was pointing out.


Mark Dekker


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drs. Mark R. Dekker
Experimentele & arbeidspsychologie
Rijksuniversiteit Groningen
Grote Kruisstraat 2/1
9712 TS Groningen
The Netherlands

tel: +31 (0)50 3636346 (work)
     +31 (0)50 5733932 (home)
fax: +31 (0)20 7778112
e-mail: m.r.dekker at ppsw.rug.nl
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