Forward versus backward recall: Modality testing

Objectives: One of the most frequently applied paradigms in the clinical and experimental fields for assessing working memory is the simple span task, composed of forward and backward recall conditions. However, the utility of the simple span measures and their relation to working memory modalities has yet to be elucidated. The current study aimed to address which of the span measures is more sensitive to the differentiation between forward and backward recall in the tactile, verbal, and visuo-spatial modalities, and to test if working memory modalities differ in the disparity between the two conditions. Methods: 134 healthy young adults performed the Tactual, Digit, and Visuo-spatial Span tasks, producing Total Correct scores and Longest Sequence score measures. Results: There was an interaction effect for condition and modality type, showing better performance for the forward compared to the backward recall in both measures. However, the effect size of the Longest Sequence score was significantly higher than the Total Correct score in all tasks. Furthermore, the Visuo-spatial Span exhibited a larger difference between forward and backward recall compared to the Digit and Tactual Span, whereas no difference was found between the latter two. Conclusions: Forward and backward recall are distinguished in all three modalities, and the Longest Sequence score is more sensitive to differentiate between storage and manipulation components of working memory than the Total Correct score. Additionally, the cognitive demand imposed by manipulation compared to storage is the greatest in the visuo-spatial modality.