A model linking immediate serial recall, the Hebb repetition effect and the learning of phonological word forms

Abstract

We briefly review the considerable evidence for a common ordering mechanism underlying both immediate serial recall (ISR) tasks (e.g. digit span, non-word repetition) and the learning of phonological word forms. In addition, we discuss how recent work on the Hebb repetition effect is consistent with the idea that learning in this task is itself a laboratory analogue of the sequence-learning component of phonological word-form learning. In this light, we present a unifying modelling framework that seeks to account for ISR and Hebb repetition effects, while being extensible to word-form learning. Because word-form learning is performed in the service of later word recognition, our modelling framework also subsumes a mechanism for word recognition from continuous speech. Simulations of a computational implementation of the modelling framework are presented and are shown to be in accordance with data from the Hebb repetition paradigm.

Figure 1.

The structure of the model.

Figure 2.

A graph showing ISR performance under various conditions of the Hebb repetition effect. For the sake of clarity, various of the conditions are portrayed using a single line representing Hebb repetition learning. The individual simulations showed that learning in these conditions followed essentially the same course (as per the data in Cumming et al. submitted); the line depicts one simulated condition rather than an average across conditions. A positive repetition effect is seen under all conditions, up to and including 12-apart repetitions, except where there is item overlap between the repeating-list and filler-list item sets. When there is overlap of this sort, there is repetition learning for 2-apart repetition, but not for 6-apart, in accordance with Melton (1963). Squares, repeat: 12-apart, 9-apart, 6-apart, 3-apart (all non-overlap), 2-apart (overlap); diamonds, repeat: 6-apart (overlap); triangles, non-repeating fillers.

Figure 3.

A graph showing a positive repetition effect for each of two alternating and repeating lists. There was no overlap in item set between the lists. The triangle indicates performance, after learning has occurred, for a list derived from the first repeating list, in which alternating items (starting with the first) are maintained in the same positions as in the learned list, with the remaining items moving (cf. Cumming et al. 2003). Diamonds, repeating 1; squares, repeating 2; triangles, alternating items maintained from r1.