PhD THESIS AVAILABLE: A Connectionist Model for Episodic Tests

[Sverker Sikstrom]

THESIS AVAILABLE

My (Sverker Sikström) thesis "TECO: A connectionist Model for Dependency
in Successive Episodic Tests" is now available for anonymous download in
postscript format at the following url-site:

http://www.psy.umu.se/personal/thesis.ps.gz

The file is approximately 1MB and unfolds to 3MB. The thesis includes 180
pages.  You may also download it from my homepage:

http://www.psy.umu.se/personal/Sverker.html

The ABSTRACT is as follows:

Sikström, P. S. TECO: A connectionist Model for Dependency in Successive
Episodic Tests. Doctoral dissertation, Department of Psychology, Ume
University, S-90187 Ume, Sweden, 1996; ISBN 91-7191-155-3

Data from a large number of experimental conditions in published studies
have shown that recognition and cued recall exhibit a moderate dependency
described by the Tulving-Wiseman function. Exceptions from this lawfulness,
in the form of higher dependency, are found when the recall test lacks
effective cues (i.e., free recall exceptions) or when the recognition test
is cued (i.e., cued recognition exceptions). In Study I, the TECO (Target,
Event, Cue & Object) theory for dependency in successive tests, is proposed
to account for the dependence between recognition and cued recall through
the fact that both tests are cued with the instruction to retrieve from the
learning episode (i.e., the event). Independence is accounted by
differences in cueing; the recall test is cued by a contextual cue, whereas
the recognition test is cued by the target. A quantitative degree of
dependence, measured by ß, is predicted to be one-third by counting the
number of shared cues divided by the total number of cues. Free recall
exceptions are predicted to reveal a dependency of one-half because the
recall test lacks effective cues. Cued recognition exceptions are predicted
to reveal a dependency of two-thirds because both tests are cued with the
cue word. A function is derived to predict the conditional probabilities
and the results show a reasonable fit with the predictions. In, Study II,
the predictions of TECO on successive tests of cued recall and cued
recognition, free recall and cued recognition, recognition, free recall and
cued recall, recognition and cued recognition is tested. A database is
presented for successive episodic tests. In, Study III the lawfulness of
recognition failure is discussed. Hintzman claimed that the conditional
probability of recognition given recall is constrained by the P(Rn)/P(Rc)
boundary and that the phenomenon of recognition failure is, thus, a
mathematical artefact. It is argued that this boundary is due to a
psychological process and that this boundary carries important information
regarding the underlying system. Furthermore, half of the deviation from
the predictive function of recognition given cued recall is shown to arise
from the lack of statistical power. In Study IV, TECO is simulated in a
neural network of a Hopfield type. A theoretical analysis is proposed and
nine sets of simulations are conducted. The results show that the theory
can be simulated with reasonable agreement to empirical data.


Keywords. Episodic memory, recognition failure, successive tests,
lawfulness, connectionism.


Feel free to contact me on the following address
Email:sverker.sikstrom at psy.umu.se

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PhD Sverker Sikstrom, Department of Psychology
s90187 Ume University, Sweden
Tel: ++46-90-166759, Fax: ++46-90-166695
Homepage:http://www.psy.umu.se/personal/Sverker.html
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