Decay lives (new paper)

Sat Nov 25 18:04:01 EST 2000

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Cognitive psychology textbooks often cite Waugh and Norman (1965) as
evidence that forgetting in short-term memory is determined by interference
alone -- i.e., that there is no decay.  This poses a problem for ACT-R,
in which decay is a primary mechanism of forgetting.

We show that there are indeed decay effects in the Waugh and Norman data.
The data contain a presentation rate x serial position interaction that,
despite being reliable, replicable, and rather obvious, has been ignored
since the data were published.  Our model explains the interaction in a
structural (parameter-insensitive) way, in terms of decay moderating the
effects of interference.  This moderating relationship is based on
functional logic, which says that without decay the cognitive system would
grind to a halt due to interference.  The same model provides an improved
account of Peterson and Peterson (1959) -- data classically used to argue
for decay alone.  To put the work in context, we survey a set of undergrad
psychology textbooks for their conclusions about decay and interference.

Decay in the model is described by ACT-R's (optimized) base-level learning
equation, and interference by the chunk choice equation.  ACT-R's retrieval
threshold is not a factor -- retrieval probability is solely a function of
target activation relative to distractor activation.

Manuscript and models are at http://www.msu.edu/~ema/ramodels.  This is
recently submitted, and comments are welcome.

Erik and Chris.

A Relative Activation Model of Memory:
Integrating Decay and Interference to Reinterpret Some Classical Data

Erik M. Altmann and Christian D. Schunn

A long-running debate in cognitive psychology concerns the processes 
of forgetting: How is information lost from human memory? The debate 
has often focussed on the question of decay (indexed by time) versus 
interference (indexed by the addition of distracting information to 
memory).  The relative activation model is a formal model grounded in 
extant memory theory that incorporates both processes.  The 
functional basis for integrating the two processes is that decay 
mitigates interference.  The empirical justification is that the 
model explains a previously- ignored interaction in a data set that 
is commonly used to argue for interference over decay (Waugh & 
Norman, 1965). The model also provides an improved account of data 
that were an original basis of decay theory (Peterson & Peterson, 
1959).
-- 

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Erik M. Altmann
Department of Psychology
Michigan State University
East Lansing, MI  48824
517-353-4406 (voice)
517-353-1652 (fax)
ema at msu.edu
http://www.msu.edu/~ema
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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<div><br></div>
<div>Cognitive psychology textbooks often cite Waugh and Norman
(1965) as</div>
<div>evidence that forgetting in short-term memory is determined by
interference</div>
<div>alone -- i.e., that there is no decay.  This poses a
problem for ACT-R,</div>
<div>in which decay is a primary mechanism of forgetting.<br>
 <br>
We show that there are indeed decay effects in the Waugh and Norman
data. </div>
<div>The data contain a presentation rate x serial position
interaction that,</div>
<div>despite being reliable, replicable, and rather obvious, has been
ignored<br>
since the data were published.  Our model explains the
interaction in a<br>
structural (parameter-insensitive) way, in terms of decay moderating
the<br>
effects of interference.  This moderating relationship is based
on<br>
functional logic, which says that without decay the cognitive system
would<br>
grind to a halt due to interference.  The same model provides an
improved<br>
account of Peterson and Peterson (1959) -- data classically used to
argue<br>
for decay alone.  To put the work in context, we survey a set of
undergrad<br>
psychology textbooks for their conclusions about decay and
interference.<br>
<br>
Decay in the model is described by ACT-R's (optimized) base-level
learning<br>
equation, and interference by the chunk choice equation. 
ACT-R's retrieval<br>
threshold is not a factor -- retrieval probability is solely a
function of<br>
target activation relative to distractor activation.<br>
<br>
Manuscript and models are at http://www.msu.edu/~ema/ramodels. 
This is<br>
recently submitted, and comments are welcome.<br>
</div>
<div>Erik and Chris.</div>
<div><br></div>
<div><br></div>
<div><font face="Times New Roman" size="+2" color="#000000">A
Relative Activation Model of Memory:<br>
Integrating Decay and Interference to Reinterpret Some Classical
Data</font></div>
<div><font face="Times New Roman" size="+2"
color="#000000"><br></font></div>
<div><font face="Times New Roman" size="+2" color="#000000">Erik M.
Altmann and Christian D. Schunn</font></div>
<div><font face="Times New Roman" size="+2"
color="#000000"><br></font></div>
<div><font face="Times" size="+2" color="#000000">A long-running
debate in cognitive psychology concerns the processes of forgetting:
How is information lost from human memory? The debate has often
focussed on the question of decay (indexed by time) versus
interference (indexed by the addition of distracting information to
memory).  The relative activation model is a formal model
grounded in extant memory theory that incorporates both
processes.  The functional basis for integrating the two
processes is that decay mitigates interference.  The empirical
justification is that the model explains a previously- ignored
interaction in a data set that is commonly used to argue for
interference over decay</font><font face="Times New Roman" size="+2"
color="#000000"> (Waugh & Norman, 1965)</font><font face="Times"
size="+2" color="#000000">. The model also provides an improved
account of data that were an original basis of decay
theory</font><font face="Times New Roman" size="+2" color="#000000">
(Peterson & Peterson, 1959)</font><font face="Times" size="+2"
color="#000000">.</font></div>

<div>-- <br>
<br>
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~<br>
Erik M. Altmann<br>
Department of Psychology<br>
Michigan State University<br>
East Lansing, MI  48824<br>
517-353-4406 (voice)  <br>
517-353-1652 (fax)<br>
ema at msu.edu<br>
http://www.msu.edu/~ema<br>
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~</div>
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