A Fundamental Limitation of the Conjunctive Codes Learned in PDP Models of Cognition: Comment on Botvinick and Plaut (2006)

Autor/inn/en	Bowers, Jeffrey S.; Damian, Markus F.; Davis, Colin J.
Titel	A Fundamental Limitation of the Conjunctive Codes Learned in PDP Models of Cognition: Comment on Botvinick and Plaut (2006)
Quelle	In: Psychological Review, 116 (2009) 4, S.986-995 (10 Seiten) PDF als Volltext Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	0033-295X
DOI	10.1037/a0017097
Schlagwörter	Stellungnahme; Short Term Memory; Models; Coding; Orthographic Symbols + Suchen Sie Ihr Suchwort? Kurzzeitgedächtnis; Analogiemodell; Codierung; Programmierung
Abstract	A central claim shared by most recent models of short-term memory (STM) is that item knowledge is coded independently from order in long-term memory (LTM; e.g., the letter A is coded by the same representational unit whether it occurs at the start or end of a sequence). Serial order is computed by dynamically binding these item codes to a separate representation of order. By contrast, Botvinick and Plaut (2006) developed a parallel distributed processing (PDP) model of STM that codes for item-order information conjunctively, such that the same letter in different positions is coded differently in LTM. Their model supports a wide range of memory phenomena, and critically, STM is better for lists that include high, as opposed to low, sequential dependencies (e.g., bigram effects). Models with context-independent item representations do not currently account for sequential effects. However, we show that their PDP model is too sensitive to these effects. A modified version of the model does better but still fails in important respects. The successes and failures can be attributed to a fundamental constraint associated with context-dependent representations. We question the viability of conjunctive coding schemes to support STM and take these findings as problematic for the PDP approach to cognition more generally. (Contains 3 footnotes and 7 figures.) (As Provided).
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Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2017/4/10