Date of Award

Spring 1-1-2012

Document Type


Degree Name

Master of Arts (MA)


Psychology & Neuroscience

First Advisor

Alice F. Healy

Second Advisor

Lyle E. Bourne

Third Advisor

Akira Miyake


In 5 experiments, subjects received and then followed the same navigation instructions presented in either words or arrows, which directed them to move in a 3-dimensional space represented as stacked, 2-dimensional matrices on a computer screen. When neither verbal nor spatial rehearsal was impeded by a dual task, and sufficient processing time was permitted, overall accuracy for implementing the move sequences with a computer mouse was equivalent for processing sequences of directional words and arrows. However, when verbal rehearsal was disrupted by a dual, articulatory suppression task, accuracy for words declined more than for arrows, and when spatial rehearsal was disrupted by a dual, pattern tapping task, only accuracy for arrows declined. Subjects' self-reported rehearsal strategies were significantly biased towards including the unimpeded modality in rehearsal. In this experimental series, the bias of the stimulus type (verbal for words and spatial for arrows) predicted how successful was rehearsal in the unimpeded modality. Importantly, the locus of the impact of pre-existing modality biases in long-term memory (LTM) on recall appears to be at rehearsal and not at encoding. It is possible that pre-existing asymmetries in modality biases in LTM may be incorporated into working memory representations such that they impact subsequent rehearsal of such representations.