Memory for Serial Order: A Network Model of the Phonological Loop and its Timing

A connectionist model of human short-term memory is presented that extends the `phonological loop' (A. D. Baddeley, 1986) to encompass serial order and learning. Psychological and neuropsychological data motivate separate layers of lexical, timing and input and output phonemic information. Connection weights between layers show Hebbian learning and decay over short and long time scales. At recall, the timing signal is rerun, phonemic information feeds back from output to input and lexical nodes compete to be selected. The selected node then receives decaying inhibition. The model provides an explanatory mechanism for the phonological loop, and for the e ects of serial position, presentation modality, lexicality, grouping and Hebb repetition. It makes new psychological and neuropsychological predictions and is a starting point for understanding the role of the phonological loop in vocabulary acquisition and for interpreting data from functional neuroimaging. Author note. Neil Burgess, Institute of Cognitive Neuroscience & Department of Anatomy, University College London, U.K.; Graham J. Hitch, Department of Psychology, University of Lancaster, Lancaster LA1 4YF, U.K. We thank Rik Henson, Tim Shallice, George Houghton, Giuseppe Vallar, John O'Keefe and Chris Yeo for useful discussions, Ian Neath and Stephan Lewandowsky for helpful suggestions during review and Rik Henson and George Houghton for reading an earlier version of this manuscript. NB is a Royal Society University Research Fellow, this research was supported by a BBSRC project grant. Correspondence should be addressed to Neil Burgess, Institute of Cognitive Neuroscience & Department of Anatomy, University College London, London WC1E 6BT, UK. Electronic mail may be sent to [email protected]. Short title: A network model of STM for serial order.