The development of the current state buffer
This thesis examines a component of Short Term Memory that is responsible for automatically tracking important stimuli in our immediate environment. The component has been termed the "Current State Buffer" (Abeles and Morton, submitted; Barreau, 1997; Barreau and Morton, submitted-, Morton, 1997), and it is argued that current conceptions of the Working Memory model (e. g. Baddeley & Hitch, 1993) do not adequately specify its role as a separate functional element of Short Term Memory. A Developmental perspective was adopted for investigating the Current State Buffer experimentally. The data was collected through the implementation of a novel task (the "Tidy Emu Paradigm"), which involved pre-school children watching an Emu glove puppet tidy away toys into receptacles. The paradigm employed dual-task methodology, consistent with many other studies of Working Memory. The empirical work reported falls into three principal stages. The first demonstrates the Current State Buffer's existence as independent to Working Memory. The lack of interference between performance on a Current State Buffer task and a Visuospatial Sketchpad task was taken as evidence for this. Other explanations for the finding are considered, and further experiments replicate the basic finding. The second stage analyses the architecture of a system that comprises a Current State Buffer and Working Memory. In brief, the data are best described by an architecture where information enters an Environmental Input Buffer, and depending on the nature of the stimulus, it passes either into the Current State Buffer, or into an Interpreter Buffer (Working Memory). At retrieval, the contents of these buffers can independently proceed to an Output Buffer. The final stage explores the effects of increasing the load of the Current State Buffer task. This revealed age-related capacity limitations in Current State Buffer function, and that subjects used age-related strategies to deal with the increase in character load, involving interactions between the Current State Buffer and Working Memory.