[ACT-R-users] New ACT-R software release available

[Ion Juvina]

Hi Dan, 

Thanks for the update. 

I have a question: what is the theoretical rationale for adding the adaptive noise to declarative memories? 

As I understand it now, I think this mechanism is (at best) unnecessary. 

It is unnecessary because the effect of noise DOES already decrease with practice. Practice increases the difference in activation between relevant and irrelevant chunks, which decreases the confusion between the two kinds of chunks at retrieval. If noise is set in the appropriate range, its effect will diminish and approach zero with practice.      

Adding an explicit parameter to achieve something that emerges from existing mechanisms may even be detrimental considering the general recommendation to keep the number of parameters to a minimum. 

I may be wrong, which is why I want to hear the rationale and the data that would suggest such an addition to the architecture. 

I’d appreciate comments from the community as well. 
 
Thanks, 
~ ion

 
     
> On Dec 21, 2016, at 10:18 AM, db30 at andrew.cmu.edu wrote:
> 
> 
> A new version of the ACT-R 7 software is now available from the
> ACT-R website: <https://urldefense.proofpoint.com/v2/url?u=http-3A__act-2Dr.psy.cmu.edu_software_&d=CwICAg&c=3buyMx9JlH1z22L_G5pM28wz_Ru6WjhVHwo-vpeS0Gk&r=vtA7YXGBFnFocyRUneK5pkvCTPZEpjEwzP4TURDawmo&m=wAdy6WChw5TkZMFPkFE8jcYsmZfwF2YmsHAsT47QsHc&s=8bxD85GR4gpHnN3lrnNM5SgWDsPGYOLFrlvMrkpwv3I&e= >.  The current
> version is now 7.3-<2102:2016-12-20>.
> 
> A few of the notable changes are listed below.  More details
> can be found in the commit log found on the ACT-R website at:
> <https://urldefense.proofpoint.com/v2/url?u=http-3A__act-2Dr.psy.cmu.edu_log_actr6log.txt&d=CwICAg&c=3buyMx9JlH1z22L_G5pM28wz_Ru6WjhVHwo-vpeS0Gk&r=vtA7YXGBFnFocyRUneK5pkvCTPZEpjEwzP4TURDawmo&m=wAdy6WChw5TkZMFPkFE8jcYsmZfwF2YmsHAsT47QsHc&s=EKW0s8sMl4vPuMe6ewyS2uJvdAAcfsZA9UOlE2y7zO4&e= >, but only the changes
> in the actr7 branch are relevant to the current software.
> 
> Production compilation has been updated to better handle buffers
> which are strict harvested.  It is now safer because it will not
> compose productions which have a stuffed chunk between them for
> goal and imaginal type buffers in cases where strict harvesting
> was the reason the buffer cleared in the first production.  It
> also produces better composed productions in situations were
> strict harvesting clears the buffer and the second production
> tests that it is empty.  Previously the 'buffer empty' query from
> the second production was added to the composed production, but
> that prevents the composed production from competing with the
> first parent.  Now that query is dropped from the new production.
> 
> The mod-focus command now makes the modification during the
> goal-modification event instead of directly.  This allows one to use
> goal-focus followed by a mod-focus without it complaining that the
> buffer is empty.
> 
> Added an extra which implements a modification to the activation
> calculation for declarative memory.  The purpose of the modifiction
> is to decrease the effect of noise on the activation of chunks as
> their activation increases with practice.  The extras/adaptive-noise
> directory contains the code which adds a parameter called :uan
> (use adaptive-noise) that can be set to t to enable the mechanism.
> The documentation included with the extra describes how it works,
> and there are some sample graphs of the results of some very simple
> test cases showing the change when :uan is enabled.
> 
> 
> If you have any questions or problems with the new version please let
> me know.
> 
> Dan
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