TR: What does the human memory environment look like?

[Simon Dennis]

The following technical report is available for anonymous ftp.


	What does the environment look like? Setting the scene for
		interactive models of human memory



			Simon Dennis
		Department of Computer Science
		    University of Queensland 

			Janet Wiles
	Departments of Computer Science and Psychology
		    University of Queensland

			Michael Humphreys
		    Department of Psychology
		    University of Queensland


Abstract

We set the scene for a class of interactive models of human memory in
which performance is dependent both on the structure of the
environment and the structure of the model's mechanism. Such a system
is capable of learning representations, control processes and decision
criterion in order to successfully interact with its environment. That
the (observable) environment is responsible for performance in
interactive models allows the elimination of assumptions which are
embedded in the mechanism of current models. Interactive models also
offer the possibility of addressing the development of the mechanisms
of memory which are currently poorly understood.

Analyses of the relevant environments of four touchstone phenomena:
the list strength effect in recognition; the crossed associates
paradigm; the ABABr paradigm and the word frequency effect in
recognition were performed to establish the context in which
interactive accounts of these phenomena must be set.  The rational
model of human memory (Anderson & Milson, 1989) is advocated as a model of
environmental contingencies and hence of interest to the interactive
modelers.  It is found to be consistent with empirical environmental
data in the case of the list strength effect and, with some
modification, in the case of the word frequency effect in recognition.
While it proved difficult to analyze the relevant environment in the
cued recall paradigms, the rational model was found to be consistent
with experimental evidence.  The issues involved in the process of
environmental analysis were explored.


Conclusions 

Our major purpose has been to set the scene for interactive models of
human memory and we have done this in three ways. Firstly, we
addressed the philosophical issue of how a representation attains its
meaning. We argued that models which have as their basis the physical
symbol system hypothesis, will encounter difficulties with the symbol
grounding problem, and will find it difficult to give an account of
meaning attainment. Interactive models provided a way of avoiding the
problem.

Secondly, we set the psychological modeling scene by outlining the
advantages of interactive models as models of human memory. Not only
do interactive models provide a much needed link to the developmental
literature, but they also allow mechanistic accounts to shed some of
their assumptions onto the observable environment.

Thirdly, we have started the task of analyzing the environment. The
environmental analyses which have been conducted are encouraging
especially for the recognition paradigms. An environmental analysis of
the effect of repetition suggests that not only is the main effect of
repetition on performance accuracy accounted for by a simple
interactivist account, but the lack of a list strength effect in
recognition is also a natural consequence of the environmental
contingencies. The word frequency effect in recognition was also found
to mirror environmental statistics while the joint information
paradigms proved difficult to analyze. Rational analysis was successful
with only minor modification in all cases examined. Given these
results there is reason to suppose that the environmental approach has
a valuable contribution to make to the understanding of human memory.

In conclusion then we would like to draw out two important
implications. Firstly, we reiterate \citeA{Anderson90}, in suggesting
that memory researchers should divert some of their effort to the
empirical study of the environment. Secondly, we propose that
interactive models of memory will be in the best position to take
advantage of such research.
 



Ftp instructions:

To retrieve the technical report ftp to exstream.cs.uq.oz.au, cd
pub/TECHREPORTS/department, change to binary mode and get TR0249.ps.Z.

Example:

$ ftp exstream.cs.uq.oz.au
Connected to exstream.cs.uq.oz.au.
220 exstream FTP server (Version 6.12 Fri May 8 16:33:17 EST 1992) ready.
Name (exstream.cs.uq.oz.au:mav): anonymous
331 Guest login ok, send e-mail address as password.
Password:
230-                 Welcome to ftp.cs.uq.oz.au
230-This is the University of Queensland Computer Science Anonymous FTP server. 
230-For people outside of the department, please restrict your usage to outside
230-of the hours 8am to 6pm.
230-
230-The local time is Thu Nov 12 11:18:01 1992
230-
230 Guest login ok, access restrictions apply.
ftp> cd pub/TECHREPORTS/department
250 CWD command successful.
ftp> bin
200 Type set to I.
ftp> get TR0249.ps.Z
200 PORT command successful.
150 Opening BINARY mode data connection for TR0249.ps.Z (174928 bytes).
226 Transfer complete.
local: TR0249.ps.Z remote: TR0249.ps.Z
174928 bytes received in 1.4 seconds (1.2e+02 Kbytes/s)
ftp> quit
221 Goodbye.
$

Please address requests for hard copies to:

Simon Dennis
Department of Computer Science
University of Queensland 4072
Australia


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Simon Dennis                  Address: Department of Computer Science
Email: mav at cs.uq.oz.au                 University of Queensland
                                       QLD 4072
                                       Australia
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