Verbal Short-term Memory: Cognitive and Neuroscientific Tests of a Perceptual-gestural Account

The store-based and perceptual-gestural accounts of verbal STM suggest that any impairment (e.g. by concurrent oral activity) of articulatory planning/production processes will also impair verbal STM. In contrast, the interference-based Feature Model argues that a concurrent oral activity is only disruptive for STM performance because it introduces irrelevant verbal item features, which interfere with the internal representations of the to-be-remembered material. This chapter reports the first studies to show that chewing gum, a non-verbal constraint on articulation, impairs verbal short-term recall of both item-order and item-identity. Experiment 1 showed that chewing gum reduces serial recall of letter lists. Experiment 2 indicated that chewing does not simply disrupt vocal-articulatory planning required for order retention: chewing equally impairs a matched task that required retention of list item identity. Experiment 3 demonstrated that manual tapping produces a similar pattern of impairment to that of chewing gum. These results pose a problem for verbal STM theories asserting that forgetting is based on domain-specific interference.