title: How is the serial order of a verbal sequence coded? Some comparisons between models.
abstract: Current models of verbal short-term memory (STM) propose various mechanisms for serial order. These include a gradient of activation over items, associations between items, and associations between items and their positions relative to the start or end of a sequence. We compared models using a variant of Hebb's procedure in which immediate serial recall of a sequence improves if the sequence is presented more than once. However, instead of repeating a complete sequence, we repeated different aspects of serial order information common to training lists and a subsequent test list. In Experiment 1, training lists repeated all the item-item pairings in the test list, with or without the position-item pairings in the test list. Substantial learning relative to a control condition was observed only when training lists repeated item-item pairs with position-item pairs, and position was defined relative to the start rather than end of a sequence. Experiment 2 attempted to analyse the basis of this learning effect further by repeating fragments of the test list during training, where fragments consisted of either isolated position-item pairings or clusters of both position-item and item-item pairings. Repetition of sequence fragments led to only weak learning effects. However, where learning was observed it was for specific position-item pairings. We conclude that positional cues play an important role in the coding of serial order in memory but that the information required to learn a sequence goes beyond position-item associations. We suggest that whereas STM for a novel sequence is based on positional cues, learning a sequence involves the development of some additional representation of the sequence as a whole.
authors.affiliation: Department of Psychology, University of York, York YO10 5DD, UK. G.Hitch@psych.york.ac.uk
authors.forename: Graham J
authors.initials: GJ
authors.lastname: Hitch
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Fastame
authors.forename: Brenda
authors.initials: B
authors.lastname: Flude
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001245:Association Learning; D006801:Humans; D007802:Language; D008570:Memory, Short-Term; D011939:Mental Recall; D008960:Models, Psychological; D011336:Probability; D011581:Psychological Tests; D012691:Serial Learning; D014706:Verbal Learning